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Volume 29
Issue 9
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Molecules, Volume 29, Issue 9 (May-1 2024) – 258 articles

Cover Story (view full-size image): The accumulation of non-biodegradable organic compounds in the aquatic environment poses a serious threat to water and its biota. Here, we have investigated mono- and bimetallic formulations based on Co, Cu, Fe and Mn, for the Fenton-like treatment of three model organic dyes (methylene blue, rhodamine B and malachite green). These systems remove the target molecules with very high efficiency rates, under mild reaction conditions. The Mn-Fe catalyst results in the best formulation with an almost complete degradation of methylene blue and malachite green at pH 5 in 5 minutes and of rhodamine B at pH 3 in 30 minutes. The results suggest that these formulations can be proposed for the treatment of a broad range of liquid wastes containing complex and variable organic pollutants. View this paper
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18 pages, 5858 KiB  
Article
A 4D-Printable Photocurable Resin Derived from Waste Cooking Oil with Enhanced Tensile Strength
by Yan Liu, Meng-Yu Liu, Xin-Gang Fan, Peng-Yu Wang and Shuo-Ping Chen
Molecules 2024, 29(9), 2162; https://doi.org/10.3390/molecules29092162 - 6 May 2024
Cited by 1 | Viewed by 1524
Abstract
In pursuit of enhancing the mechanical properties, especially the tensile strength, of 4D-printable consumables derived from waste cooking oil (WCO), we initiated the production of acrylate-modified WCO, which encompasses epoxy waste oil methacrylate (EWOMA) and epoxy waste oil acrylate (EWOA). Subsequently, a series [...] Read more.
In pursuit of enhancing the mechanical properties, especially the tensile strength, of 4D-printable consumables derived from waste cooking oil (WCO), we initiated the production of acrylate-modified WCO, which encompasses epoxy waste oil methacrylate (EWOMA) and epoxy waste oil acrylate (EWOA). Subsequently, a series of WCO-based 4D-printable photocurable resins were obtained by introducing a suitable diacrylate molecule as the second monomer, coupled with a composite photoinitiator system comprising Irgacure 819 and p-dimethylaminobenzaldehyde (DMAB). These materials were amenable to molding using an LCD light-curing 3D printer. Our findings underscored the pivotal role of triethylene glycol dimethacrylate (TEGDMA) among the array of diacrylate molecules in enhancing the mechanical properties of WCO-based 4D-printable resins. Notably, the 4D-printable material, composed of EWOA and TEGDMA in an equal mass ratio, exhibited nice mechanical strength comparable to that of mainstream petroleum-based 4D-printable materials, boasting a tensile strength of 9.17 MPa and an elongation at break of 15.39%. These figures significantly outperformed the mechanical characteristics of pure EWOA or TEGDMA resins. Furthermore, the EWOA-TEGDMA resin demonstrated impressive thermally induced shape memory performance, enabling deformation and recovery at room temperature and retaining its shape at −60 °C. This resin also demonstrated favorable biodegradability, with an 8.34% weight loss after 45 days of soil degradation. As a result, this 4D-printable photocurable resin derived from WCO holds immense potential for the creation of a wide spectrum of high-performance intelligent devices, brackets, mold, folding structures, and personalized products. Full article
(This article belongs to the Special Issue Advances of Oleochemistry and Its Application)
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Full article ">Figure 1
<p>Schematic illustration of the preparation and 4D printing process of the WCO-based photocurable resin.</p> Full article ">Figure 2
<p>(<b>a</b>) IR spectra of 4D-printed product and liquid resin of A2 sample; (<b>b</b>–<b>d</b>) The full XPS (<b>b</b>), C1s (<b>c</b>), and O1s (<b>d</b>) high-resolution XPS spectra of 4D-printed product of A2 resin.</p> Full article ">Figure 3
<p>(<b>a</b>,<b>b</b>) Tensile properties (<b>a</b>) and impact toughness (<b>b</b>) of pure EWOA and WCO-based 4D-printable resins composed of EWOA and different diacrylate molecules; (<b>c</b>) Schematic illustration of the structural differences between the curing products of EWOA-TEGDMA resin and pure EWOA.</p> Full article ">Figure 4
<p>(<b>a</b>,<b>c</b>) The tensile properties (<b>a</b>) and impact toughness (<b>c</b>) of EWOA/EWOMA-TEGDMA resins with different dosages of TEGDMA at room temperature; (<b>b</b>) The comparison of mechanical properties between the resulting WCO-based resin (A2 and MA2 sample) and other petroleum-based photocurable resins for 4D printing; (<b>d</b>,<b>e</b>) The tensile properties of the A2 (<b>d</b>) and MA2 (<b>e</b>) resin at different temperatures.</p> Full article ">Figure 5
<p>Shape memory cycle of a 4D-printed rectangular thin film (<b>a</b>) and radish roots (<b>b</b>) of A2 resin.</p> Full article ">Figure 6
<p>(<b>a</b>,<b>b</b>) The shape memory behaviour curves of A2 (<b>a</b>) and MA2 (<b>b</b>) resin; (<b>c</b>,<b>d</b>) The fixity ratio (<span class="html-italic">R<sub>f</sub></span>, (<b>c</b>)) and recovery ratio (<span class="html-italic">R<sub>r</sub></span>, (<b>d</b>)) of A2 and MA2 resin within ten shape memory cycles; (<b>a</b>–<b>d</b>) were all carried out with a fixing temperature of –60 °C and a recovering temperature of 25 °C. (<b>e</b>,<b>f</b>) The DSC spectra of A2 (<b>e</b>) and MA2 (<b>f</b>) resin; (<b>g</b>) The <span class="html-italic">R<sub>f</sub></span> of A2 resin in water at different fixing temperatures; (<b>h</b>) The <span class="html-italic">R<sub>r</sub></span> of A2 resin in water at different recovering temperatures.</p> Full article ">Figure 7
<p>Schematic illustration of the structural transformation in EWOA-TEGDMA resin during a shape memory cycle.</p> Full article ">Figure 8
<p>Biodegradation rates of EWOA-TEGDMA resin (A2 sample) and commercial 3D printing resin measured by the weight loss.</p> Full article ">
18 pages, 707 KiB  
Review
BCM-7: Opioid-like Peptide with Potential Role in Disease Mechanisms
by Ecem Bolat, Furkan Eker, Selin Yılmaz, Sercan Karav, Emel Oz, Charles Brennan, Charalampos Proestos, Maomao Zeng and Fatih Oz
Molecules 2024, 29(9), 2161; https://doi.org/10.3390/molecules29092161 - 6 May 2024
Cited by 8 | Viewed by 5801
Abstract
Bovine milk is an essential supplement due to its rich energy- and nutrient-rich qualities. Caseins constitute the vast majority of the proteins in milk. Among these, β-casein comprises around 37% of all caseins, and it is an important type of casein with several [...] Read more.
Bovine milk is an essential supplement due to its rich energy- and nutrient-rich qualities. Caseins constitute the vast majority of the proteins in milk. Among these, β-casein comprises around 37% of all caseins, and it is an important type of casein with several different variants. The A1 and A2 variants of β-casein are the most researched genotypes due to the changes in their composition. It is accepted that the A2 variant is ancestral, while a point mutation in the 67th amino acid created the A1 variant. The digestion derived of both A1 and A2 milk is BCM-7. Digestion of A2 milk in the human intestine also forms BCM-9 peptide molecule. The opioid-like characteristics of BCM-7 are highlighted for their potential triggering effect on several diseases. Most research has been focused on gastrointestinal-related diseases; however other metabolic and nervous system-based diseases are also potentially triggered. By manipulating the mechanisms of these diseases, BCM-7 can induce certain situations, such as conformational changes, reduction in protein activity, and the creation of undesired activity in the biological system. Furthermore, the genotype of casein can also play a role in bone health, such as altering fracture rates, and calcium contents can change the characteristics of dietary products. The context between opioid molecules and BCM-7 points to a potential triggering mechanism for the central nervous system and other metabolic diseases discussed. Full article
(This article belongs to the Section Food Chemistry)
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<p>Formation of BCM-7 and BCM-9 cow’s milk peptides.</p> Full article ">
20 pages, 4695 KiB  
Article
Identification of New Hepatic Metabolites of Miconazole by Biological and Electrochemical Methods Using Ultra-High-Performance Liquid Chromatography Combined with High-Resolution Mass Spectrometry
by Michał Wroński, Jakub Trawiński and Robert Skibiński
Molecules 2024, 29(9), 2160; https://doi.org/10.3390/molecules29092160 - 6 May 2024
Cited by 1 | Viewed by 1247
Abstract
The main objective of this study was to investigate the metabolism of miconazole, an azole antifungal drug. Miconazole was subjected to incubation with human liver microsomes (HLM) to mimic phase I metabolism reactions for the first time. Employing a combination of an HLM [...] Read more.
The main objective of this study was to investigate the metabolism of miconazole, an azole antifungal drug. Miconazole was subjected to incubation with human liver microsomes (HLM) to mimic phase I metabolism reactions for the first time. Employing a combination of an HLM assay and UHPLC-HRMS analysis enabled the identification of seven metabolites of miconazole, undescribed so far. Throughout the incubation with HLM, miconazole underwent biotransformation reactions including hydroxylation of the benzene ring and oxidation of the imidazole moiety, along with its subsequent degradation. Additionally, based on the obtained results, screen-printed electrodes (SPEs) were optimized to simulate the same biotransformation reactions, by the use of a simple, fast, and cheap electrochemical method. The potential toxicity of the identified metabolites was assessed using various in silico models. Full article
(This article belongs to the Special Issue The Application of LC-MS in Pharmaceutical Analysis)
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Figure 1
<p>MS/MS spectrum and fragmentation pattern of miconazole.</p> Full article ">Figure 2
<p>MS/MS spectrum and fragmentation pattern of M1.</p> Full article ">Figure 3
<p>MS/MS spectrum and fragmentation pattern of M2.</p> Full article ">Figure 4
<p>MS/MS spectrum and fragmentation pattern of M3.</p> Full article ">Figure 5
<p>MS/MS spectrum and fragmentation pattern of M4.</p> Full article ">Figure 6
<p>MS/MS spectrum and fragmentation pattern of M5.</p> Full article ">Figure 7
<p>MS/MS spectrum and fragmentation pattern of M6.</p> Full article ">Figure 8
<p>MS/MS spectrum and fragmentation pattern of M7.</p> Full article ">Figure 9
<p>The hepatic metabolic pathway of miconazole (* Metabolite not formed by electrochemical experiments).</p> Full article ">Figure 10
<p>Formation of miconazole metabolites during HLM incubation.</p> Full article ">Figure 11
<p>A 3D plot of principal component analysis comparing the biological HLM and electrochemical profiles of miconazole (Y-Axis—PC1, Z-Axis—PC2, X-Axis—PC3).</p> Full article ">Figure 12
<p>Plot of principal component analysis of calculated aquatic toxicity of miconazole metabolites towards different aquatic organisms ((<b>A</b>)—fish, (<b>B</b>)—<span class="html-italic">D. magna</span>, (<b>C</b>)—algae, (<b>D</b>)—rodents).</p> Full article ">
18 pages, 10785 KiB  
Article
Divergent Synthesis of 5,7-Diazaullazines Derivatives through a Combination of Cycloisomerization with Povarov or Alkyne–Carbonyl Metathesis
by Jonas Polkaehn, Peter Ehlers, Alexander Villinger and Peter Langer
Molecules 2024, 29(9), 2159; https://doi.org/10.3390/molecules29092159 - 6 May 2024
Viewed by 1177
Abstract
Ullazines and their π-expanded derivatives have gained much attention as active components in various applications, such as in organic photovoltaic cells or as photosensitizers for CO2 photoreduction. Here, we report the divergent synthesis of functionalized diazaullazines by means of two different domino-reactions [...] Read more.
Ullazines and their π-expanded derivatives have gained much attention as active components in various applications, such as in organic photovoltaic cells or as photosensitizers for CO2 photoreduction. Here, we report the divergent synthesis of functionalized diazaullazines by means of two different domino-reactions consisting of either a Povarov/cycloisomerization or alkyne–carbonyl metathesis/cycloisomerization protocol. The corresponding quinolino-diazaullazine and benzoyl-diazaullazine derivatives were obtained in moderate to good yields. Their optical and electronic properties were studied and compared to related, literature-known compounds to obtain insights into the impact of nitrogen doping and π-expansion. Full article
(This article belongs to the Section Organic Chemistry)
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Graphical abstract
Full article ">Figure 1
<p>Potential modifications to ullazine.</p> Full article ">Figure 2
<p>X-ray structures of <b>5c</b>.</p> Full article ">Figure 3
<p>(<b>A</b>) NICS calculations for pyrimido[4′,5′,6′:9,1]pyrrolo[2′,1′,5′:4,5,6]quinolizino[3,2-<span class="html-italic">b</span>]quinoline: NICS2BC graphs (current was calculated from NICS(1.25)<sub>ZZ</sub> strength relative to I<sub>ref</sub> (ring current of benzene, 11.5 nA T<sup>−1</sup>)). In the center of each ring are the respective NICS(1.7)<sub>ZZ</sub> values. (<b>B</b>) Ortep of <b>5c</b> with C-C bond length of the core structure (left) and plane angle between the pyrimido-indolizine and the quinoline moieties.</p> Full article ">Figure 4
<p>UV/Vis (<b>left</b>) and PL spectra ((<b>right</b>), λ<sub>ex</sub> = 480 nm (<b>5a</b>,<b>k</b>,<b>l</b>), λ<sub>ex</sub> = 400 nm (<b>6a</b>)) of the compounds shown in CH<sub>2</sub>Cl<sub>2</sub> (c = 10<sup>−5</sup> M) at 20 °C.</p> Full article ">Figure 5
<p>Cyclic voltammograms of <b>5a</b> and <b>6a</b>. Measured in CH<sub>2</sub>Cl<sub>2</sub> (0.001 M) with 0.1 M n-Bu<sub>4</sub>NPF<sub>6</sub> as a supporting electrolyte, glassy carbon working electrode, and Pt counter-electrode, with ferrocene as a standard, at a scan rate of 100 mV/s.</p> Full article ">Figure 6
<p>Frontier orbitals of <b>5a</b>, <b>5k</b>, <b>5l,</b> and <b>6a</b>, and energy levels calculated at the B3LYP/6-31G(d,p) level of theory within IEFPCM in CH<sub>2</sub>Cl<sub>2</sub>.</p> Full article ">Scheme 1
<p>Divergent synthesis of Chen and our approach with the synthesis quinolino-diazaullazines and benzoyl-diazaullazines.</p> Full article ">Scheme 2
<p>Synthesis of ACM and Povarov precursors <b>4a</b>–<b>f</b>; <span class="html-italic">i</span>: 2,5-dimethoxytetrahydrofuran, acetic acid, 1,2-dichloroethane, reflux, 3 h. <span class="html-italic">ii</span>: POCl<sub>3</sub> (2.0 eq.), DMF, 100 °C, 3 h. <span class="html-italic">iii</span>: alkyne (3 eq.), PdCl<sub>2</sub>(CH<sub>3</sub>CN)<sub>2</sub> (0.06 eq.), XPhos (0.12 eq.), CuI (0.04 eq.), HN<sup>i</sup>Pr<sub>2</sub>, 1,4-dioxane, 90 °C, 24 h.</p> Full article ">Scheme 3
<p>Synthesis of final products <b>5a</b>–<b>l</b> by Povarov/cycloisomerization and <b>6a</b>–<b>f</b> by ACM/cycloisomerization. (<b>a</b>) 1. FeCl<sub>3</sub> (1 eq.), corresponding aniline (1.2 eq.), xylene, 140 °C, 3 h; 2. <span class="html-italic">p</span>-TsOH∙H<sub>2</sub>O (30 eq.), xylene, 140 °C, 6 h. (<b>b</b>) <span class="html-italic">p</span>-TsOH∙H<sub>2</sub>O (20 eq.), xylene, 120 °C, 6 h.</p> Full article ">
14 pages, 2968 KiB  
Article
Chromium Catalysts for Selective Ethylene Oligomerization Featuring Binuclear PNP Ligands
by Xiangyang Meng, Zhiqiang Ding, Huan Gao, Zhe Ma, Li Pan, Bin Wang and Yuesheng Li
Molecules 2024, 29(9), 2158; https://doi.org/10.3390/molecules29092158 - 6 May 2024
Viewed by 1825
Abstract
A series of novel binuclear PNP ligands based on the cyclohexyldiamine scaffold were synthesized for this study. The experimental results showed that positioning the two PNP sites at the para-positions of the cyclohexyl framework led to a significant enhancement in the catalytic activity [...] Read more.
A series of novel binuclear PNP ligands based on the cyclohexyldiamine scaffold were synthesized for this study. The experimental results showed that positioning the two PNP sites at the para-positions of the cyclohexyl framework led to a significant enhancement in the catalytic activity for selective tri/tetramerization of ethylene. The PNP/Cr(acac)3/MAO(methylaluminoxane) catalytic system exhibited relatively high catalytic activity (up to 3887.7 kg·g−1·h−1) in selective ethylene oligomerization with a total selectivity of 84.5% for 1-hexene and 1-octene at 40 °C and 50 bar. The relationship between the ligand structure and ethylene oligomerization performance was further explored using density functional theory calculations. Full article
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Figure 1
<p>Synthesis of binuclear PNP-type ligands and the molecular structure of <b>L2</b>.</p> Full article ">Figure 2
<p>(<b>a</b>) The impact of ligand structure on catalytic activity and selectivity. (<b>b</b>) Ethylene consumption curves of PNP ligands 1–5.</p> Full article ">Figure 3
<p>(<b>a</b>) The impact of temperature on catalytic activity and selectivity. (<b>b</b>) The impact of ethylene pressure on catalytic activity and selectivity. (<b>c</b>) The impact of the Al/Cr molar ratios on catalytic activity and selectivity.</p> Full article ">Figure 4
<p>Steric maps of five ligands. The <span class="html-italic">z</span>-axis is defined by the nitrogen atom and its connected carbon atom, while the xz-plane is determined by the <span class="html-italic">z</span>-axis and a carbon atom on the phenyl ring.</p> Full article ">Figure 5
<p>The trends in ethylene oligomerization activity and 1-octene selectivity with variations in the steric hindrance of the ligands 2–4.</p> Full article ">Figure 6
<p>Charge density profiles of <b>L1</b>-<b>L5</b> and the average charge on the phosphorus atom.</p> Full article ">Scheme 1
<p>(<b>A</b>) Classical PP-type ligands used for ethylene oligomerization; (<b>B</b>) Classical PN-type ligands used for ethylene oligomerization; (<b>C</b>) Classical PNP-type ligands used for ethylene oligomerization; (<b>D</b>) Binuclear PNP-type ligands based on in this work.</p> Full article ">
16 pages, 6991 KiB  
Article
A Comparative Study of Cerium(III) and Cerium(IV) Phosphates for Sunscreens
by Taisiya O. Kozlova, Darya N. Vasilyeva, Daniil A. Kozlov, Irina V. Kolesnik, Maria A. Teplonogova, Ilya V. Tronev, Ekaterina D. Sheichenko, Maria R. Protsenko, Danil D. Kolmanovich, Olga S. Ivanova, Alexander E. Baranchikov and Vladimir K. Ivanov
Molecules 2024, 29(9), 2157; https://doi.org/10.3390/molecules29092157 - 6 May 2024
Cited by 3 | Viewed by 1915
Abstract
Crystalline cerium(III) phosphate (CePO4), cerium(IV) phosphates, and nanocrystalline ceria are considered to be promising components of sunscreen cosmetics. This paper reports on a study in which, for the first time, a quantitative comparative analysis was performed of the UV-shielding properties of [...] Read more.
Crystalline cerium(III) phosphate (CePO4), cerium(IV) phosphates, and nanocrystalline ceria are considered to be promising components of sunscreen cosmetics. This paper reports on a study in which, for the first time, a quantitative comparative analysis was performed of the UV-shielding properties of CePO4, Ce(PO4)(HPO4)0.5(H2O)0.5, and CePO4/CeO2 composites. Both the sun protection factor and protection factor against UV-A radiation of the materials were determined. Ce(PO4)(HPO4)0.5(H2O)0.5 was shown to have a sun protection factor of 2.9, which is comparable with that of nanocrystalline ceria and three times higher than the sun protection factor of CePO4. Composites containing both cerium dioxide and CePO4 demonstrated higher sun protection factors (up to 1.8) than individual CePO4. When compared with the TiO2 Aeroxide P25 reference sample, cerium(III) and cerium(IV) phosphates demonstrated negligible photocatalytic activity. A cytotoxicity analysis performed using two mammalian cell lines, hMSc and NCTC L929, showed that CePO4, Ce(PO4)(HPO4)0.5(H2O)0.5, and nanocrystalline ceria were all non-toxic. The results of this comparative study indicate that cerium(IV) phosphate Ce(PO4)(HPO4)0.5(H2O)0.5 is more advantageous for use in sunscreens than either cerium(III) phosphate or CePO4/CeO2 composites, due to its improved UV-shielding properties and low photocatalytic activity. Full article
(This article belongs to the Section Applied Chemistry)
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Full article ">Figure 1
<p>The scheme of the synthesis of ceric phosphate, Ce(PO<sub>4</sub>)(HPO<sub>4</sub>)<sub>0.5</sub>(H<sub>2</sub>O)<sub>0.5</sub>, and CePO<sub>4</sub>/CeO<sub>2</sub> composites.</p> Full article ">Figure 2
<p>Appearance of ceria, cerium phosphates, and CePO<sub>4</sub>/CeO<sub>2</sub> composites (optical images).</p> Full article ">Figure 3
<p>Diffraction patterns of ceria, cerium phosphates, and CePO<sub>4</sub>/CeO<sub>2</sub> composites.</p> Full article ">Figure 4
<p>IR spectra of CeO<sub>2</sub>, cerium phosphates, and composite samples.</p> Full article ">Figure 5
<p>Raman spectra of ceria and composites samples.</p> Full article ">Figure 6
<p>SEM images of (<b>a</b>) CeHP, (<b>b</b>) C48-700, (<b>c</b>) C48-1000, (<b>d</b>) C96-700, (<b>e</b>) C96-1000, and (<b>f</b>) CeP samples.</p> Full article ">Figure 7
<p>SEM images in the backscattered electron mode for the CePO<sub>4</sub>/CeO<sub>2</sub> composites and corresponding EDX maps of cerium (yellow), phosphorous (green), and oxygen (red).</p> Full article ">Figure 8
<p>Averaged UV–vis absorption spectra of the suspensions containing ceria, cerium phosphates, and CePO<sub>4</sub>/CeO<sub>2</sub> composites.</p> Full article ">Figure 9
<p>(<b>a</b>) Kinetic curves of methylene blue dye photodegradation in the presence of CeP, CeHP, C48-700, ceria, and TiO<sub>2</sub> Aeroxide TiO<sub>2</sub> P25 samples; and (<b>b</b>) normalised photocatalytic activity (PCA) for the corresponding samples.</p> Full article ">Figure 10
<p>Metabolic activity of (<b>a</b>) human mesenchymal stem cells and (<b>b</b>) mouse fibroblasts of the NCTC L929 line after 48 h of cultivation with the CeP sample in concentrations of 1, 0.5, 0.25, and 0.125 mg/mL. Seeding density was 20,000 cm<sup>−2</sup>. M ± SD, Mann–Whitney U-test, at <span class="html-italic">p</span> = 0.05.</p> Full article ">Figure 11
<p>Appearance of L929 mouse fibroblasts in the presence of the CeP sample. Images were taken at 200× magnification. Scale bar—200 μm. SYTO 9 and propidium iodide dyes (live/dead test) were used. Green—live cells, red—dead cells.</p> Full article ">
12 pages, 1786 KiB  
Communication
Photoredox-Catalyzed Decarboxylative Cross-Coupling Reaction to Synthesis Unsymmetrical Diarylmethanes
by Guozhe Guo, Yuquan Zhang, Yanchun Li and Zhijun Li
Molecules 2024, 29(9), 2156; https://doi.org/10.3390/molecules29092156 - 6 May 2024
Viewed by 1462
Abstract
The photoredox-catalyzed decarboxylative cross-coupling reaction of aryl acetic acids and aryl nitriles has been achieved under an argon atmosphere in high yields. This method provides a fast way to obtain prevalent aryl acetic acids from an abundant natural source. A tentative radical mechanism [...] Read more.
The photoredox-catalyzed decarboxylative cross-coupling reaction of aryl acetic acids and aryl nitriles has been achieved under an argon atmosphere in high yields. This method provides a fast way to obtain prevalent aryl acetic acids from an abundant natural source. A tentative radical mechanism has been proposed. Full article
(This article belongs to the Special Issue Organic Synthesis and Application of Bioactive Molecules)
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Full article ">Figure 1
<p>The represent drugs containing diarylmethane scaffolds.</p> Full article ">Scheme 1
<p>The conventional methods toward synthesis of diarylmethanes.</p> Full article ">Scheme 2
<p>Gram-scale synthesis.</p> Full article ">Scheme 3
<p>Control experiments.</p> Full article ">Scheme 4
<p>Proposed mechanism.</p> Full article ">
13 pages, 3296 KiB  
Article
Untargeted Metabolomics Based on Ultra-High-Performance Liquid Chromatography Coupled with Quadrupole Orbitrap High-Resolution Mass Spectrometry for Differential Metabolite Analysis of Pinelliae Rhizoma and Its Adulterants
by Jing Wang, Jie Cui, Ziyi Liu, Yang Yang, Zhan Li and Huiling Liu
Molecules 2024, 29(9), 2155; https://doi.org/10.3390/molecules29092155 - 6 May 2024
Cited by 2 | Viewed by 1635
Abstract
The present study investigates the chemical composition variances among Pinelliae Rhizoma, a widely used Chinese herbal medicine, and its common adulterants including Typhonium flagelliforme, Arisaema erubescens, and Pinellia pedatisecta. Utilizing the non-targeted metabolomics technique of employing UHPLC-Q-Orbitrap HRMS, this research [...] Read more.
The present study investigates the chemical composition variances among Pinelliae Rhizoma, a widely used Chinese herbal medicine, and its common adulterants including Typhonium flagelliforme, Arisaema erubescens, and Pinellia pedatisecta. Utilizing the non-targeted metabolomics technique of employing UHPLC-Q-Orbitrap HRMS, this research aims to comprehensively delineate the metabolic profiles of Pinelliae Rhizoma and its adulterants. Multivariate statistical methods including PCA and OPLS-DA are employed for the identification of differential metabolites. Volcano plot analysis is utilized to discern upregulated and downregulated compounds. KEGG pathway analysis is conducted to elucidate the differences in metabolic pathways associated with these compounds, and significant pathway enrichment analysis is performed. A total of 769 compounds are identified through metabolomics analysis, with alkaloids being predominant, followed by lipids and lipid molecules. Significant differential metabolites were screened out based on VIP > 1 and p-value < 0.05 criteria, followed by KEGG enrichment analysis of these differential metabolites. Differential metabolites between Pinelliae Rhizoma and Typhonium flagelliforme, as well as between Pinelliae Rhizoma and Pinellia pedatisecta, are significantly enriched in the biosynthesis of amino acids and protein digestion and absorption pathways. Differential metabolites between Pinelliae Rhizoma and Arisaema erubescens are mainly enriched in tyrosine metabolism and phenylalanine metabolism pathways. These findings aim to provide valuable data support and theoretical references for further research on the pharmacological substances, resource development and utilization, and quality control of Pinelliae Rhizoma. Full article
(This article belongs to the Section Analytical Chemistry)
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Full article ">Figure 1
<p>(<b>A</b>) The distribution of metabolic substances in BX, SBX, TNX, and HZNZ. (<b>B</b>) Venn diagram of metabolite distribution in BX, SBX, TNX, and HZNZ. (<b>C</b>) 3D PCA of metabolites identified from BX, SBX, TNX, and HZNZ. (<b>D</b>) HCA exhibiting correlation among BX, SBX, TNX, and HZNZ.</p> Full article ">Figure 2
<p>(<b>A</b>–<b>C</b>) OPLS-DA score plot of BX vs. SBX, BX vs. TNX, and BX vs. HZNX, respectively. (<b>D</b>–<b>F</b>) OPLS-DA permutation plot of BX vs. SBX, BX vs. TNX, and BX vs. HZNX, respectively.</p> Full article ">Figure 3
<p>(<b>A</b>–<b>C</b>) Volcano plot of differential metabolites among BX vs. SBX, BX vs. TNX, and BX vs. HZNX, respectively. (<b>D</b>–<b>F</b>) Heatmap clustering exhibiting correlation among BX vs. SBX, BX vs. TNX, and BX vs. HZNX, respectively.</p> Full article ">Figure 4
<p>Venn plot of the number of differential metabolites among BX vs. SBX, BX vs. TNX, and BX vs. HZNX.</p> Full article ">Figure 5
<p>K-means clustering of differential metabolites profiles.</p> Full article ">Figure 6
<p>(<b>A</b>–<b>C</b>) KEGG enrichment map of differential metabolites among BX vs. SBX, BX vs. TNX, and BX vs. HZNX, respectively.</p> Full article ">Figure 6 Cont.
<p>(<b>A</b>–<b>C</b>) KEGG enrichment map of differential metabolites among BX vs. SBX, BX vs. TNX, and BX vs. HZNX, respectively.</p> Full article ">
16 pages, 18851 KiB  
Article
Poria cocos Attenuated DSS-Induced Ulcerative Colitis via NF-κB Signaling Pathway and Regulating Gut Microbiota
by Xiaojun Song, Wei Wang, Li Liu, Zitong Zhao, Xuebin Shen, Lingyun Zhou, Yuanxiang Zhang, Daiyin Peng and Sihui Nian
Molecules 2024, 29(9), 2154; https://doi.org/10.3390/molecules29092154 - 6 May 2024
Cited by 3 | Viewed by 1965
Abstract
Ulcerative colitis (UC), as a chronic inflammatory disease, presents a global public health threat. However, the mechanism of Poria cocos (PC) in treating UC remains unclear. Here, LC-MS/MS was carried out to identify the components of PC. The protective effect of PC against [...] Read more.
Ulcerative colitis (UC), as a chronic inflammatory disease, presents a global public health threat. However, the mechanism of Poria cocos (PC) in treating UC remains unclear. Here, LC-MS/MS was carried out to identify the components of PC. The protective effect of PC against UC was evaluated by disease activity index (DAI), colon length and histological analysis in dextran sulfate sodium (DSS)-induced UC mice. ELISA, qPCR, and Western blot tests were conducted to assess the inflammatory state. Western blotting and immunohistochemistry techniques were employed to evaluate the expression of tight junction proteins. The sequencing of 16S rRNA was utilized for the analysis of gut microbiota regulation. The results showed that a total of fifty-two nutrients and active components were identified in PC. After treatment, PC significantly alleviated UC-associated symptoms including body weight loss, shortened colon, an increase in DAI score, histopathologic lesions. PC also reduced the levels of inflammatory cytokines TNF-α, IL-6, and IL-1β, as evidenced by the suppressed NF-κB pathway, restored the tight junction proteins ZO-1 and Claudin-1 in the colon, and promoted the diversity and abundance of beneficial gut microbiota. Collectively, these findings suggest that PC ameliorates colitis symptoms through the reduction in NF-κB signaling activation to mitigate inflammatory damage, thus repairing the intestinal barrier, and regulating the gut microbiota. Full article
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<p>PCE relieves DSS-induced colitis in mice. (<b>A</b>) Perianal condition in mice; (<b>B</b>) weight change during the experiment; (<b>C</b>) disease activity index (DAI) score; (<b>D</b>,<b>E</b>) representative images of colon length on d7; (<b>F</b>) spleen coefficients. PCE-L, low dose of PCE; PCE-M, medium dose of PCE; PCE-H, high dose of PCE. The values are expressed as mean ± SD (<span class="html-italic">n</span> = ten mice in each group) <sup>##</sup> <span class="html-italic">p</span> &lt; 0.01, <sup>###</sup> <span class="html-italic">p</span> &lt; 0.001 vs. control group; * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001 vs. model group.</p> Full article ">Figure 2
<p>PCE ameliorates DSS-induced intestinal structural damage in UC mice. (<b>A</b>) Representative H&amp;E staining of colon tissue (200×); (<b>B</b>) histological score of H&amp;E staining; (<b>C</b>) Alician staining of goblet cells (400×); (<b>D</b>) histological score of Alician staining. Red arrow indicates inflammatory damage before and after administration in the blank group and the model group. The values are expressed as mean ± SD (<span class="html-italic">n</span> = 3). <sup>##</sup> <span class="html-italic">p</span> &lt; 0.01, <sup>###</sup> <span class="html-italic">p</span> &lt; 0.001 vs. control group; * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001 vs. model group.</p> Full article ">Figure 3
<p>PCE decreased inflammatory cytokine levels in serum and colon tissue. (<b>A</b>,<b>B</b>) The expressions of TNF-α, IL-6, and IL-1β levels in serum and colonic tissue revealed by ELISA, respectively; (<b>C</b>) the mRNA expressions of TNF-α, IL-1β, and IL-6 were detected by performing qPCR. The values are expressed as the means ± SD (<span class="html-italic">n</span> = 3 of independent experiments in vitro), <sup>###</sup> <span class="html-italic">p</span> &lt; 0.001 vs. control group; * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, and *** <span class="html-italic">p</span> &lt; 0.001 vs. DSS group.</p> Full article ">Figure 4
<p>PCE inhibits ΙκΒα/ΝF-κΒ activity. (<b>A</b>) Immunoblots of ΙκΒα, P-ΙκΒα, and iNOS in the colon tissue of mice; (<b>B</b>,<b>C</b>) protein expression chart. The values are expressed as mean ± SD (<span class="html-italic">n</span> = 3 of independent experiments in vitro), <sup>###</sup> <span class="html-italic">p</span> &lt; 0.001 vs. control group; * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001 vs. DSS group.</p> Full article ">Figure 5
<p>PCE attenuates DSS-induced damage to the TJs of intestinal epithelium in mice. (<b>A</b>–<b>D</b>) TJ proteins Claudin-1 and ZO-1 were observed by immunohistochemistry; (<b>E</b>–<b>G</b>) the expression of ZO-1, Claudin-1 proteins were determined by Western blotting. Red arrow indicates TJs damage before and after administration in the blank group and the model group. The values are expressed as mean ± SD (<span class="html-italic">n</span> = 3 of independent experiments in vitro), <sup>##</sup> <span class="html-italic">p</span> &lt; 0.01, <sup>###</sup> <span class="html-italic">p</span> &lt; 0.001 vs. control group; * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001 vs. DSS group.</p> Full article ">Figure 6
<p>Intestinal flora analyses in mice. (<b>A</b>) Alpha diversity; (<b>B</b>) abundance curve; (<b>C</b>) principal coordinates analysis; (<b>D</b>) non-metric multidimensional scaling. The values are expressed as mean ± SD. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, and *** <span class="html-italic">p</span> &lt; 0.001 vs. DSS group.</p> Full article ">Figure 7
<p>Intestinal microbiota species composition changes in mice. (<b>A</b>) Venn diagram; (<b>B</b>–<b>H</b>) relative abundance comparisons between <span class="html-italic">Proteobacteria</span>, <span class="html-italic">Firmicutes</span>, <span class="html-italic">Pseudomonas</span>, <span class="html-italic">Oscillospira</span>, <span class="html-italic">Prevotella</span>, <span class="html-italic">Ruminococcus</span>, and unidentified-<span class="html-italic">Lachnospiraceae</span> in three groups, respectively. <sup>#</sup> <span class="html-italic">p</span> &lt; 0.05, <sup>##</sup> <span class="html-italic">p</span> &lt; 0.01, and <sup>###</sup> <span class="html-italic">p</span> &lt; 0.001 vs. control group; The values are expressed as mean ± SD, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001 vs. DSS group.</p> Full article ">
14 pages, 2074 KiB  
Article
Efficacy and Functional Mechanisms of a Two-Stage Pretreatment Approach Based on Alkali and Ionic Liquid for Bioconversion of Waste Medium-Density Fiberboard
by Shujie Wang, Xianfeng Hou, Jin Sun, Dan Sun and Zhenzhong Gao
Molecules 2024, 29(9), 2153; https://doi.org/10.3390/molecules29092153 - 6 May 2024
Cited by 1 | Viewed by 1163
Abstract
A novel pretreatment strategy utilizing a combination of NaOH and 1-Butyl-3-methylimidazolium chloride ([Bmim]Cl) was proposed to enhance the enzymatic hydrolysis of abandoned Medium-density fiberboard (MDF). The synergistic effect of NaOH and [Bmim]Cl pretreatment significantly improved the glucose yield, reaching 445.8 mg/g within 72 [...] Read more.
A novel pretreatment strategy utilizing a combination of NaOH and 1-Butyl-3-methylimidazolium chloride ([Bmim]Cl) was proposed to enhance the enzymatic hydrolysis of abandoned Medium-density fiberboard (MDF). The synergistic effect of NaOH and [Bmim]Cl pretreatment significantly improved the glucose yield, reaching 445.8 mg/g within 72 h, which was 5.04 times higher than that of the untreated samples. The working mechanism was elucidated according to chemical composition, as well as FTIR, 13C NMR, XRD, and SEM analyses. The combined effects of NaOH and [Bmim]Cl led to lignin degradation, hemicellulose removal, the destruction and erosion of crystalline regions, pores, and an irregular microscopic morphology. In addition, by comparing the enzymatic hydrolysis sugar yield and elemental nitrogen content of untreated MDF samples, eucalyptus, and hot mill fibers (HMF), it was demonstrated that the presence of adhesives and additives in waste MDF significantly influences its hydrolysis process. The sugar yield of untreated MDF samples (88.5 mg/g) was compared with those subjected to hydrothermal pretreatment (183.2 mg/g), Ionic liquid (IL) pretreatment (406.1 mg/g), and microwave-assisted ionic liquid pretreatment (MWI) (281.3 mg/g). A long water bath pretreatment can reduce the effect of adhesives and additives on the enzymatic hydrolysis of waste MDF. The sugar yield produced by the combined pretreatment proposed in this study and the removal ability of adhesives and additives highlight the great potential of our pretreatment technology in the recycling of waste fiberboard. Full article
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<p>Effect of pretreatment time of AAI on glucose yield.</p> Full article ">Figure 2
<p>The oily substance in the sand core funnel (10 g MDF sample).</p> Full article ">Figure 3
<p>FT-IR spectra of the raw MDF, NaOH-pretreated, and AAI-pretreated MDF: 1—untreated MDF; 2—NaOH pretreated; 3—AAI pretreated.</p> Full article ">Figure 4
<p><sup>13</sup>C NMR spectra of raw MDF and NaOH- and AAI-pretreated MDF.</p> Full article ">Figure 5
<p>XRD diffractograms of the raw MDF, NaOH-pretreated, and AAI-pretreated MDF; 1—untreated MDF; 2—NaOH pretreated; 3—AAI pretreated.</p> Full article ">Figure 6
<p>SEM images of (<b>a</b>) untreated MDF; (<b>b</b>) NaOH-pretreated MDF; (<b>c</b>) AAI-pretreated MDF.</p> Full article ">
11 pages, 2032 KiB  
Article
Unveiling the Low-Lying Spin States of [Fe3S4] Clusters via the Extended Broken-Symmetry Method
by Shibing Chu and Qiuyu Gao
Molecules 2024, 29(9), 2152; https://doi.org/10.3390/molecules29092152 - 6 May 2024
Viewed by 1138
Abstract
Photosynthetic water splitting, when synergized with hydrogen production catalyzed by hydrogenases, emerges as a promising avenue for clean and renewable energy. However, theoretical calculations have faced challenges in elucidating the low-lying spin states of iron–sulfur clusters, which are integral components of hydrogenases. To [...] Read more.
Photosynthetic water splitting, when synergized with hydrogen production catalyzed by hydrogenases, emerges as a promising avenue for clean and renewable energy. However, theoretical calculations have faced challenges in elucidating the low-lying spin states of iron–sulfur clusters, which are integral components of hydrogenases. To address this challenge, we employ the Extended Broken-Symmetry method for the computation of the cubane–[Fe3S4] cluster within the [FeNi] hydrogenase enzyme. This approach rectifies the error caused by spin contamination, allowing us to obtain the magnetic exchange coupling constant and the energy level of the low-lying state. We find that the Extended Broken-Symmetry method provides more accurate results for differences in bond length and the magnetic coupling constant. This accuracy assists in reconstructing the low-spin ground state force and determining the geometric structure of the ground state. By utilizing the Extended Broken-Symmetry method, we further highlight the significance of the geometric arrangement of metal centers in the cluster’s properties and gain deeper insights into the magnetic properties of transition metal iron–sulfur clusters at the reaction centers of hydrogenases. This research illuminates the untapped potential of hydrogenases and their promising role in the future of photosynthesis and sustainable energy production. Full article
(This article belongs to the Special Issue Photocatalytic Materials and Photocatalytic Reactions)
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<p>The diagram illustrates the [NiFe], [Fe<sub>4</sub>S<sub>3</sub>], [Fe<sub>3</sub>S<sub>4</sub>], and [Fe<sub>4</sub>S<sub>4</sub>] clusters involved in the catalytic pathway, as well as the distances between each cluster.</p> Full article ">Figure 2
<p>The structure of the [Fe<sub>3</sub>S<sub>4</sub>(CH<sub>3</sub>CH<sub>2</sub>SH)<sub>3</sub>]<sup>2−</sup> complex. Iron is represented in orange, sulfur in yellow, carbon in black, and hydrogen in gray.</p> Full article ">Figure 3
<p>(<b>a</b>) Shows the comparison of Δ<span class="html-italic">r</span> using HS, BS, and EBS methods with the B3LYP hybrid functional. (<b>b</b>) Shows the same comparison using the TPSSh hybrid functional.</p> Full article ">Figure 4
<p>Comparison of the spin ladder of the GS and high−spin state calculated using the B3LYP functional. The blue lines represent the spin ladder of the high−spin state, and the red lines represent the spin ladder of the GS. After the optimization of the structure using the EBS method, the calculated energy difference between GS and HS states is 4828.44 cm<sup>−1</sup>.</p> Full article ">Figure 5
<p>Comparison of the spin ladder of the GS and high–spin state calculated using the TPSSh functional. The blue lines represent the spin ladder of the high–spin state, and the red lines represent the spin ladder of the GS. After the optimization of the structure with the EBS method, the calculated energy difference between GS and HS states is 7498.35 cm<sup>−1</sup>.</p> Full article ">Figure 6
<p>(<b>a</b>) Depicts the 8 broken symmetry states of the cubane–[Fe<sub>3</sub>S<sub>4</sub>] cluster, complete with spin details. The energy level of the low-lying state (LS state) is illustrated in (<b>c</b>), where the total spins <span class="html-italic">S</span><sub>tot</sub> of 1/2 and 3/2 are shown. This implies that there are 7 pairs of electrons and 1 single electron in the state with <span class="html-italic">S</span> = 1/2 and 6 pairs of electrons and 3 spin-up electrons in the state with <span class="html-italic">S</span> = 3/2. The energy in (<b>c</b>) is derived from calculations of cubane–[Fe<sub>3</sub>S<sub>4</sub>] clusters using the B3LYP functional. The magnetic coupling constant <span class="html-italic">J</span> can be extracted from the SVD matrix. The Clebsch–Gordan transformation, represented in (<b>b</b>), enables the description of the cluster’s GS.</p> Full article ">Figure 7
<p>Flow chart of the geometric optimization of clusters using the EBS method.</p> Full article ">
21 pages, 2955 KiB  
Article
Synthesis of 5-(Aryl)amino-1,2,3-triazole-containing 2,1,3-Benzothiadiazoles via Azide–Nitrile Cycloaddition Followed by Buchwald–Hartwig Reaction
by Pavel S. Gribanov, Anna N. Philippova, Maxim A. Topchiy, Dmitry A. Lypenko, Artem V. Dmitriev, Sergey D. Tokarev, Alexander F. Smol’yakov, Alexey N. Rodionov, Andrey F. Asachenko and Sergey N. Osipov
Molecules 2024, 29(9), 2151; https://doi.org/10.3390/molecules29092151 - 6 May 2024
Cited by 1 | Viewed by 2192
Abstract
An efficient access to the novel 5-(aryl)amino-1,2,3-triazole-containing 2,1,3-benzothiadiazole derivatives has been developed. The method is based on 1,3-dipolar azide–nitrile cycloaddition followed by Buchwald–Hartwig cross-coupling to afford the corresponding N-aryl and N,N-diaryl substituted 5-amino-1,2,3-triazolyl 2,1,3-benzothiadiazoles under NHC-Pd catalysis. The one-pot [...] Read more.
An efficient access to the novel 5-(aryl)amino-1,2,3-triazole-containing 2,1,3-benzothiadiazole derivatives has been developed. The method is based on 1,3-dipolar azide–nitrile cycloaddition followed by Buchwald–Hartwig cross-coupling to afford the corresponding N-aryl and N,N-diaryl substituted 5-amino-1,2,3-triazolyl 2,1,3-benzothiadiazoles under NHC-Pd catalysis. The one-pot diarylative Pd-catalyzed heterocyclization opens the straightforward route to triazole-linked carbazole-benzothiadiazole D-A systems. The optical and electrochemical properties of the compound obtained were investigated to estimate their potential application as emissive layers in OLED devises. The quantum yield of photoluminescence (PLQY) of the synthesized D-A derivatives depends to a large extent on electron-donating strengths of donor (D) component, reaching in some cases the values closed to 100%. Based on the most photoactive derivative and wide bandgap host material mCP, a light-emitting layer of OLED was made. The device showed a maximum brightness of 8000 cd/m2 at an applied voltage of 18 V. The maximum current efficiency of the device reaches a value of 3.29 cd/A. Full article
(This article belongs to the Special Issue Synthesis and Properties of Heterocyclic Compounds: Recent Advances)
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<p>Structure of <b>6a</b> (CCDC 2345715), <b>6g</b> (CCDC 2345713), and <b>7a</b> (CCDC 2345714).</p> Full article ">Figure 2
<p>Electronic absorption and emission spectra of <b>4b</b>, <b>5f</b>, <b>6d</b>, <b>6g</b>, and <b>7a</b> in dichloromethane, C = 2 × 10<sup>−5</sup> M.</p> Full article ">Figure 3
<p>Energy band diagram of the OLED structure with the co-deposited EML layer <b>6d</b>/mCP.</p> Full article ">Figure 4
<p>(<b>a</b>) Normalized EL spectrum; (<b>b</b>) the CIE chromaticity diagram of OLED based on co-deposited EML layer <b>6d</b>/mCP.</p> Full article ">Figure 5
<p>Current density–voltage dependence and voltage–brightness characteristics of the OLED based on EML layer <b>6d</b>/mCP.</p> Full article ">Scheme 1
<p>Synthetic approaches to: (<b>a</b>) 5-amino-1,2,3-triazoles and 5-arylamino-1,2,3-triazoles; (<b>b</b>) BTD-containing <span class="html-italic">N</span>-aryl- and <span class="html-italic">N</span>,<span class="html-italic">N</span>-diarylsubstituted 5-amino-1,2,3-triazoles.</p> Full article ">Scheme 2
<p>Synthesis of acetonitrile containing BTDs <b>3a</b> and <b>3b</b>. * Reaction conditions: <b>1</b> or <b>2</b> (1 equiv.), nitrile (1.2 equiv.), NaHCO<sub>3</sub> (3 equiv.), Pd(PPh<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub> (5 mol.%), dioxane/H<sub>2</sub>O, 100 °C, 6 h.</p> Full article ">Scheme 3
<p>Synthesis of BTD-containing 5-amino-1,2,3-triazoles <b>4a</b>–<b>g</b>. Reaction conditions: <b>3a</b> or <b>3b</b> (3 mmol), aryl (alkyl) azide (3 equiv.), KOtBu (0.5 equiv.), DMSO (8 mL), 70 °C, 3 h.</p> Full article ">Scheme 4
<p>Buchwald–Hartwig cross-coupling synthesis of <span class="html-italic">N</span>-monosubstituted arylamino-1,2,3-triazole-2,1,3-benzothiadiazoles <b>5a</b>–<b>f</b>. Reaction conditions: <b>4</b> (0.2 mmol), (het)aryl-Br (5 equiv.), (THP-Dipp)Pd(cinn)Cl (5 mol.%), NaOtBu (3 equiv.), 1,4-dioxane (1.0 mL), 110 °C, 24 h.</p> Full article ">Scheme 5
<p>The Buchwald–Hartwig cross-coupling synthesis of <span class="html-italic">N</span>,<span class="html-italic">N</span>-disubstituted-arylamino-1,2,3-triazole-2,1,3-benzothiadiazoles <b>6a</b>–<b>l</b>. Reaction conditions: 5-amino-1,2,3-triazole-2,1,3-benzothiadiazole <b>4</b> (0.2 mmol), aryl-Br (5 equiv.), (THP-Dipp)Pd(cinn)Cl (5 mol.%), <span class="html-italic">t</span>-Bu<sub>3</sub>P-HBF<sub>4</sub> (10 mol.%), NaOtBu (3 equiv.), 1,4-dioxane (1.0 mL), 110 °C, 24 h.</p> Full article ">Scheme 6
<p>One-pot diarylative cyclization synthesis of <b>7a</b>–<b>d</b>. Reaction conditions: 5-amino-1,2,3-triazole-2,1,3-benzothiadiazole <b>4</b> (0.2 mmol), 2,2′-dibromobiphenyl (1.0 equiv.), (THP-Dipp)Pd(cinn)Cl (5 mol.%), <span class="html-italic">t</span>-Bu<sub>3</sub>P-HBF<sub>4</sub> (10 mol.%), NaOtBu (3 equiv.), 1,4-dioxane (1.0 mL), 110 °C, 24 h.</p> Full article ">
3 pages, 881 KiB  
Editorial
Wastewater Treatment: Functional Materials and Advanced Technology
by Jingtao Bi and Guohui Dong
Molecules 2024, 29(9), 2150; https://doi.org/10.3390/molecules29092150 - 6 May 2024
Cited by 1 | Viewed by 1730
Abstract
With accelerated advancements in various industries, water pollution has emerged as a significant issue characterized by two features: (1) the rapid increase in population and corresponding demands, leading to a sharp rise in wastewater discharge, and (2) the development of new technologies, contributing [...] Read more.
With accelerated advancements in various industries, water pollution has emerged as a significant issue characterized by two features: (1) the rapid increase in population and corresponding demands, leading to a sharp rise in wastewater discharge, and (2) the development of new technologies, contributing to a significant increase in the variety of emerging contaminants, resulting in a more complex wastewater composition [...] Full article
(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology)
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<p>Keyword cloud of the 34 papers in the Special Issue.</p> Full article ">
16 pages, 4672 KiB  
Article
Supramolecular Gels Based on C3-Symmetric Amides: Application in Anion-Sensing and Removal of Dyes from Water
by Geethanjali Kuppadakkath, Sreejith Sudhakaran Jayabhavan and Krishna K. Damodaran
Molecules 2024, 29(9), 2149; https://doi.org/10.3390/molecules29092149 - 5 May 2024
Cited by 4 | Viewed by 1859
Abstract
We modified C3-symmetric benzene-1,3,5-tris-amide (BTA) by introducing flexible linkers in order to generate an N-centered BTA (N-BTA) molecule. The N-BTA compound formed gels in alcohols and aqueous mixtures of high-polar solvents. Rheological studies showed that the DMSO/water (1:1, v [...] Read more.
We modified C3-symmetric benzene-1,3,5-tris-amide (BTA) by introducing flexible linkers in order to generate an N-centered BTA (N-BTA) molecule. The N-BTA compound formed gels in alcohols and aqueous mixtures of high-polar solvents. Rheological studies showed that the DMSO/water (1:1, v/v) gels were mechanically stronger compared to other gels, and a similar trend was observed for thermal stability. Powder X-ray analysis of the xerogel obtained from various aqueous gels revealed that the packing modes of the gelators in these systems were similar. The stimuli-responsive properties of the N-BTA towards sodium/potassium salts indicated that the gel network collapsed in the presence of more nucleophilic anions such as cyanide, fluoride, and chloride salts at the MGC, but the gel network was intact when in contact with nitrate, sulphate, acetate, bromide, and iodide salts, indicating the anion-responsive properties of N-BTA gels. Anion-induced gel formation was observed for less nucleophilic anions below the MGC of N-BTA. The ability of N-BTA gels to act as an adsorbent for hazardous anionic and cationic dyes in water was evaluated. The results indicated that the ethanolic gels of N-BTA successfully absorbed methylene blue and methyl orange dyes from water. This work demonstrates the potential of the N-BTA gelator to act as a stimuli-responsive material and a promising candidate for water purification. Full article
(This article belongs to the Special Issue Chemistry of Materials for Energy and Environmental Sustainability)
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<p>Frequency sweep experiments of gels in various solvents/solvent mixtures at 4.0 wt/v% at 20.0 °C with a constant strain of 0.01%.</p> Full article ">Figure 2
<p>SEM images of N-BTA xerogels (2.0 wt/v%) from (<b>a</b>) methanol and (<b>b</b>) ethanol, and xerogels from (<b>c</b>) DMF/water and (<b>d</b>) DMSO/water (1:1, <span class="html-italic">v</span>/<span class="html-italic">v</span>) at 4.0 wt/v%, respectively.</p> Full article ">Figure 3
<p>PXRD patterns of the dried gels (4.0 wt/v%) from the aqueous solutions of DMF, DMSO, DEA, and DMA (1:1, <span class="html-italic">v</span>/<span class="html-italic">v</span>).</p> Full article ">Figure 4
<p>Stimuli-responsive properties of the (<b>a</b>) N-BTA gels in DMSO/water mixture (1:1, <span class="html-italic">v</span>/<span class="html-italic">v</span>) with sodium halides (1.0 equiv.), such as (<b>b</b>) fluoride, (<b>c</b>) chloride, (<b>d</b>) bromide, and (<b>e</b>) iodide salts.</p> Full article ">Figure 5
<p>Frequency sweep experiments of N-BTA gels (3.6 wt/v%) in the presence of various sodium/potassium salts of bromide, iodide, nitrate, acetate, and sulphate.</p> Full article ">Figure 6
<p>(<b>a</b>) UV-vis experiments of MB (7.5 × 10<sup>−6</sup> M) in deionized water and (<b>b</b>) upon adding the N-BTA gel prepared in ethanol (2.0 wt/v%) to MB (7.5 × 10<sup>−6</sup> M).</p> Full article ">Figure 7
<p>UV-vis: (<b>a</b>) UV-vis experiments of MO (5.0 × 10<sup>−5</sup> M) in deionized water and (<b>b</b>) upon adding the N-BTA gel prepared in ethanol (2.0 wt/v%) to MO (5.0 × 10<sup>−5</sup> M).</p> Full article ">Figure 8
<p>(<b>a</b>) UV-vis experiments of MB (7.5 × 10<sup>−5</sup> M) in deionized water with varying concentrations of N-BTA after 7 days and (<b>b</b>) adsorption ratio of MB with varying concentrations of N-BTA after 2, 5, and 7 days.</p> Full article ">Scheme 1
<p>Synthesis of N-centered <span class="html-italic">C<sub>3</sub></span>-symmetric <span class="html-italic">tris</span>-amide (N-BTA).</p> Full article ">
16 pages, 3322 KiB  
Article
Development of Novel Immobilized Copper–Ligand Complex for Click Chemistry of Biomolecules
by Rene Kandler, Yomal Benaragama, Manoranjan Bera, Caroline Wang, Rasheda Aktar Samiha, W. M. C. Sameera, Samir Das and Arundhati Nag
Molecules 2024, 29(9), 2148; https://doi.org/10.3390/molecules29092148 - 5 May 2024
Viewed by 1922
Abstract
Copper-catalyzed azide–alkyne cycloaddition click (CuAAC) reaction is widely used to synthesize drug candidates and other biomolecule classes. Homogeneous catalysts, which consist of copper coordinated to a ligand framework, have been optimized for high yield and specificity of the CuAAC reaction, but CuAAC reaction [...] Read more.
Copper-catalyzed azide–alkyne cycloaddition click (CuAAC) reaction is widely used to synthesize drug candidates and other biomolecule classes. Homogeneous catalysts, which consist of copper coordinated to a ligand framework, have been optimized for high yield and specificity of the CuAAC reaction, but CuAAC reaction with these catalysts requires the addition of a reducing agent and basic conditions, which can complicate some of the desired syntheses. Additionally, removing copper from the synthesized CuAAC-containing biomolecule is necessary for biological applications but inconvenient and requires additional purification steps. We describe here the design and synthesis of a PNN-type pincer ligand complex with copper (I) that stabilizes the copper (I) and, therefore, can act as a CuAAC catalyst without a reducing agent and base under physiologically relevant conditions. This complex was immobilized on two types of resin, and one of the immobilized catalyst forms worked well under aqueous physiological conditions. Minimal copper leaching was observed from the immobilized catalyst, which allowed its use in multiple reaction cycles without the addition of any reducing agent or base and without recharging with copper ion. The mechanism of the catalytic cycle was rationalized by density functional theory (DFT). This catalyst’s utility was demonstrated by synthesizing coumarin derivatives of small molecules such as ferrocene and sugar. Full article
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Synthesis and structure of Complex <b>1</b>. (<b>A</b>) Scheme showing the synthesis of the ligand. (a) Condensation of 2-(diphenylphosphaneyl)benzaldehyde (PBA) to imine with <span class="html-italic">N</span>-methyl propargylamine (mPA), MeOH, rt, 52 h, mPA:PBA 5:1. (b) Reduction with NaBH<sub>3</sub>CN (imine:NaBH<sub>3</sub>CN 1:4) pH 5.0–5.5, 3–24 h (c) Complexation of ligand with tetrakis(acetonitrile)copper(I) hexafluorophosphate (1.2:1.0 equivalents) in acetonitrile, 5 h; (d) In-solution click reaction of complexed ligand with methyl 2-azidoacetate, rt, 24 h. (<b>B</b>) Optimized structure of Complex <b>1</b>, employing DFT. In the optimized structure, Cu (shown in coral) is coordinated with nitrogens N1, N2, N3 (blue), and phosphorus P (orange). Oxygens in the ligand framework are shown in red, while nitrogens are denoted in blue. Cu, N1, N2, and P are in the same plane. Cu-N1 (1.95 Å) and Cu-N1 (2.04 Å) bond distances are relatively shorter compared to Cu-N3 (3.01 Å).</p> Full article ">Figure 2
<p>Immobilization of ligand on solid support to yield immobilized Complex <b>1</b>. a. Ligand: [Cu(CH<sub>3</sub>CN)<sub>4</sub>]<sup>+</sup> PF<sub>6</sub><sup>−</sup> (1.2:1.0 equivalents) in acetonitrile (ACN), 5 h; b. 1 equivalent ligand and 4 equivalents DIEA, added to 1 equivalent resin-bound azide, rt, 72 h, followed by ACN washes.</p> Full article ">Figure 3
<p>Various triazoles synthesized using immobilized Complex <b>1</b>, in addition to Triazole 1.</p> Full article ">Figure 4
<p>Repeated use of immobilized Complex <b>1</b> for the CuAAC reaction yields Triazole 3 without recharging the complex with copper. (<b>A</b>) Reaction scheme and labeled protons in alkyne and triazole; a–f refer to protons of the starting material alkyne, and 1–4 refer to the protons of the product triazole. (<b>B</b>) Percentage of Triazole 3 formation in cycles 1–10; (<b>C</b>) <sup>1</sup>H-NMR of cycles 1–10.</p> Full article ">Figure 5
<p>(<b>A</b>) Reaction used for the mechanistic study; (<b>B</b>) free energy (kcal/mol) profile of the mechanism of the catalytic cycle.</p> Full article ">Scheme 1
<p>Comparison of this work with previously reported catalysts for CuAAC reaction. (<b>A</b>) Fokin et al. [<a href="#B17-molecules-29-02148" class="html-bibr">17</a>] utilized additional copper (I) complex in the catalysis reaction. (<b>B</b>) Finn et al. [<a href="#B15-molecules-29-02148" class="html-bibr">15</a>] used free copper (II) and the reducing agent sodium ascorbate in the catalysis reaction. (<b>C</b>) The immobilized complex described in this article catalyzes without free copper and reducing agents. (<b>D</b>) Diez-Gonzales et al. [<a href="#B6-molecules-29-02148" class="html-bibr">6</a>] used the Cu(I) complex with a monodentate phosphine-containing ligand as a catalyst in solution. (<b>E</b>) The developed complex described in this article can work in solution as a CuAAC catalyst at a lower mol%. See <a href="#app1-molecules-29-02148" class="html-app">Supplementary Materials</a> for the mol percentage calculations of immobilized catalyst (*, #).</p> Full article ">
10 pages, 2229 KiB  
Article
Inkjet Printing of High-Color-Purity Blue Organic Light-Emitting Diodes with Host-Free Inks
by Hui Fang, Jiale Li, Shaolong Gong, Jinliang Lin and Guohua Xie
Molecules 2024, 29(9), 2147; https://doi.org/10.3390/molecules29092147 - 5 May 2024
Cited by 1 | Viewed by 1692
Abstract
Inkjet printing technology offers a unique approach to producing direct-patterned pixels without fine metal masks for active matrix displays. Organic light-emitting diodes (OLEDs) consisting of thermally activated delayed fluorescence (TADF) emitters facilitate efficient light emission without heavy metals, such as platinum and iridium. [...] Read more.
Inkjet printing technology offers a unique approach to producing direct-patterned pixels without fine metal masks for active matrix displays. Organic light-emitting diodes (OLEDs) consisting of thermally activated delayed fluorescence (TADF) emitters facilitate efficient light emission without heavy metals, such as platinum and iridium. Multi-resonance TADF molecules, characterized by their small full width at half maxima (FWHM), are highly suitable for the requirements of wide color-gamut displays. Herein, host-free TADF inks with a low concentration of 1 mg/mL were developed and inkjet-printed onto a seeding layer, concurrently serving as the hole-transporting layer. Attributed to the proof-of-concept of host-free inks printed on a mixed seeding layer, a maximum external quantum efficiency of 13.1% (improved by a factor of 21.8) was achieved in the inkjet-printed OLED, with a remarkably narrow FWHM of only 32 nm. Highly efficient energy transfer was facilitated by the effective dispersion of the sensitizer around the terminal emitters. Full article
(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members and Invited Scholars in Applied Chemistry)
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Figure 1

Figure 1
<p>Schematic diagram of energy level alignment of the device and chemical structures of the key materials used in the IJP devices. The sky-blue columns represent the luminescent guest molecule. The values of the energy levels were adopted from the literature.</p> Full article ">Figure 2
<p>Normalized PL spectra of (<b>a</b>) BCzBN and (<b>b</b>) SBA-2DPS:BCzBN films printed on the HTL with different dot spacings of 50, 60, 70 and 80 μm. (<b>c</b>) Normalized PL spectra of mCP and SBA-2DPS films and UV-vis absorption of the SBA-2DPS and BCzBN solution (10<sup>−5</sup> M).</p> Full article ">Figure 3
<p>Transient PL spectra of the IJP films of SBA-2DPS:BCzBN films fabricated with dot spacings of 50, 60, 70, and 80 μm detected at long (<b>a</b>) and short (<b>b</b>) time scales, as well as spin-coated films detected at long (<b>c</b>) and short (<b>d</b>) time scales.</p> Full article ">Figure 4
<p>(<b>a</b>) Normalized EL spectra. (<b>b</b>) External quantum efficiency versus current density curves of the devices with different printed dot spacings. (<b>c</b>) Current density–voltage curves. (<b>d</b>) Luminance–voltage curves.</p> Full article ">Figure 5
<p>(<b>a</b>) Normalized EL spectra. Inset: The CIE 1931 color coordinates of the IJP devices. (<b>b</b>) EQE versus current density curves. Inset: Microscopic photograph of the IJP device under electroluminescence. (<b>c</b>) Current density–voltage curves. (<b>d</b>) Luminance–voltage curves.</p> Full article ">
18 pages, 2761 KiB  
Article
Cyclometalated and NNN Terpyridine Ruthenium Photocatalysts and Their Cytotoxic Activity
by Maurizio Ballico, Dario Alessi, Eleonora Aneggi, Marta Busato, Daniele Zuccaccia, Lorenzo Allegri, Giuseppe Damante, Christian Jandl and Walter Baratta
Molecules 2024, 29(9), 2146; https://doi.org/10.3390/molecules29092146 - 5 May 2024
Viewed by 1710
Abstract
The cyclometalated terpyridine complexes [Ru(η2-OAc)(NC-tpy)(PP)] (PP = dppb 1, (R,R)-Skewphos 4, (S,S)-Skewphos 5) are easily obtained from the acetate derivatives [Ru(η2-OAc)2(PP)] (PP = dppb, (R [...] Read more.
The cyclometalated terpyridine complexes [Ru(η2-OAc)(NC-tpy)(PP)] (PP = dppb 1, (R,R)-Skewphos 4, (S,S)-Skewphos 5) are easily obtained from the acetate derivatives [Ru(η2-OAc)2(PP)] (PP = dppb, (R,R)-Skewphos 2, (S,S)-Skewphos 3) and tpy in methanol by elimination of AcOH. The precursors 2, 3 are prepared from [Ru(η2-OAc)2(PPh3)2] and Skewphos in cyclohexane. Conversely, the NNN complexes [Ru(η1-OAc)(NNN-tpy)(PP)]OAc (PP = (R,R)-Skewphos 6, (S,S)-Skewphos 7) are synthesized in a one pot reaction from [Ru(η2-OAc)2(PPh3)2], PP and tpy in methanol. The neutral NC-tpy 1, 4, 5 and cationic NNN-tpy 6, 7 complexes catalyze the transfer hydrogenation of acetophenone (S/C = 1000) in 2-propanol with NaOiPr under light irradiation at 30 °C. Formation of (S)-1-phenylethanol has been observed with 4, 6 in a MeOH/iPrOH mixture, whereas the R-enantiomer is obtained with 5, 7 (50–52% ee). The tpy complexes show cytotoxic activity against the anaplastic thyroid cancer 8505C and SW1736 cell lines (ED50 = 0.31–8.53 µM), with the cationic 7 displaying an ED50 of 0.31 µM, four times lower compared to the enantiomer 6. Full article
(This article belongs to the Special Issue Feature Papers in Photochemistry and Photocatalysis)
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Figure 1

Figure 1
<p>NMR numbering scheme of the tpy ligand in the [Ru(η<sup>2</sup>-OAc)(NC-tpy)(PP)] (<b>a</b>) and [Ru(η<sup>1</sup>-OAc)(NNN-tpy)(PP)]OAc (<b>b</b>) complexes.</p> Full article ">Figure 2
<p>ORTEP style plot of compound <b>1</b> (one out of two independent molecules) in the solid state (CCDC 2302606). Ellipsoids are drawn at the 50% probability level. Hydrogen atoms and co-crystalized solvent molecules are omitted for clarity. Selected bond lengths [Å] and angles [°]: Ru1–C7 2.026(4), Ru1–N1 2.114(3), Ru1–O1 2.231(2), Ru1–O2 2.256(3), Ru1–P1 2.2511(14), Ru1–P2 2.2709(14), C7–Ru1–N1 79.50(12), C7–Ru1–O1 105.73(11), N1–Ru1–O1 84.67(11), C7–Ru1–P1 85.82(9), N1–Ru1–P1 92.85(10), O1–Ru1–P1 167.47(6), C7–Ru1–O2 160.55(11), N1–Ru1–O2 87.21(10), O1–Ru1–O2 58.52(8), P1–Ru1–O2 109.15(6), C7–Ru1–P2 100.08(10), N1–Ru1–P2 172.82(8), O1–Ru1–P2 88.57(8), P1–Ru1–P2 94.27(6), O2–Ru1–P2 91.33(7).</p> Full article ">Figure 3
<p>Photocatalytic TH of acetophenone (0.1 M) in <span class="html-italic">i</span>PrOH/MeOH (1/1 in volume) with the NC and NNN complexes <b>5</b> and <b>7</b> at S/C = 1000 and NaO<span class="html-italic">i</span>Pr (2 mol%) at 30 °C, over time, with or without light irradiation.</p> Full article ">Scheme 1
<p>Synthesis of Ru(η<sup>2</sup>-OAc)(NC-tpy)(dppb)] (<b>1</b>).</p> Full article ">Scheme 2
<p>Synthesis of the neutral [Ru(η<sup>2</sup>-OAc)(NC-tpy)(PP)] complexes.</p> Full article ">Scheme 3
<p>Synthesis of the cationic [Ru(η<sup>1</sup>-OAc)(NNN-tpy)(PP)]OAc complexes.</p> Full article ">Scheme 4
<p>Pathways of the formation of the neutral and cationic tpy ruthenium complexes, with the proposed intermediates in the blue boxes.</p> Full article ">Scheme 5
<p>Photocatalytic transfer hydrogenation of acetophenone.</p> Full article ">Scheme 6
<p>Proposed mechanism for the photocatalytic TH of carbonyl compounds promoted by <b>4</b>–<b>7</b>, via the [RuX(NNN-tpy)((<span class="html-italic">S</span>,<span class="html-italic">S</span>)-Skewphos)](O<span class="html-italic">i</span>Pr) (X = O<span class="html-italic">i</span>Pr <b>a</b>, H <b>b</b>, OCH(Me)Ph <b>c</b>).</p> Full article ">
21 pages, 3012 KiB  
Article
Light-Emitting Diodes and Liquid System Affect the Caffeoylquinic Acid Derivative and Flavonoid Production and Shoot Growth of Rhaponticum carthamoides (Willd.) Iljin
by Ewa Skała, Monika A. Olszewska, Przemysław Tabaka and Agnieszka Kicel
Molecules 2024, 29(9), 2145; https://doi.org/10.3390/molecules29092145 - 5 May 2024
Cited by 1 | Viewed by 1185
Abstract
Plant in vitro cultures can be an effective tool in obtaining desired specialized metabolites. The purpose of this study was to evaluate the effect of light-emitting diodes (LEDs) on phenolic compounds in Rhaponticum carthamoides shoots cultured in vitro. R. carthamoides is an endemic [...] Read more.
Plant in vitro cultures can be an effective tool in obtaining desired specialized metabolites. The purpose of this study was to evaluate the effect of light-emitting diodes (LEDs) on phenolic compounds in Rhaponticum carthamoides shoots cultured in vitro. R. carthamoides is an endemic and medicinal plant at risk of extinction due to the massive harvesting of its roots and rhizomes from the natural environment. The shoots were cultured on an agar-solidified and liquid-agitated Murashige and Skoog’s medium supplemented with 0.1 mg/L of indole-3-acetic acid (IAA) and 0.5 mg/L of 6-benzyladenine (BA). The effect of the medium and different treatments of LED lights (blue (BL), red (RL), white (WL), and a combination of red and blue (R:BL; 7:3)) on R. carthamoides shoot growth and its biosynthetic potential was observed. Medium type and the duration of LED light exposure did not affect the proliferation rate of shoots, but they altered the shoot morphology and specialized metabolite accumulation. The liquid medium and BL light were the most beneficial for the caffeoylquinic acid derivatives (CQAs) production, shoot growth, and biomass increment. The liquid medium and BL light enhanced the content of the sum of all identified CQAs (6 mg/g DW) about three-fold compared to WL light and control, fluorescent lamps. HPLC-UV analysis confirmed that chlorogenic acid (5-CQA) was the primary compound in shoot extracts regardless of the type of culture and the light conditions (1.19–3.25 mg/g DW), with the highest level under R:BL light. BL and RL lights were equally effective. The abundant component was also 3,5-di-O-caffeoylquinic acid, accompanied by 4,5-di-O-caffeoylquinic acid, a tentatively identified dicaffeoylquinic acid derivative, and a tricaffeoylquinic acid derivative 2, the contents of which depended on the LED light conditions. Full article
(This article belongs to the Special Issue New Insights into Bioactive Compounds from Natural Sources)
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Figure 1

Figure 1
<p>Representative HPLC-UV chromatogram of <span class="html-italic">R. carthamoides</span> shoot extract recorded at 325 nm and 350 nm; 3-<span class="html-italic">O</span>-caffeoylquinic acid (3-CQA) (<b>1</b>); 5-<span class="html-italic">O</span>-caffeoylquinic acid (5-CQA, chlorogenic acid) (<b>2</b>); 4-<span class="html-italic">O</span>-caffeoylquinic acid (4-CQA) (<b>3</b>); quercetagetin hexoside (<b>4</b>); quercetin hexoside (<b>5</b>); luteolin hexoside (<b>6</b>); patuletin hexoside (<b>7</b>); 3,4-<span class="html-italic">O</span>-dicaffeoylquinic acid (3,4-diCQA) (<b>8</b>); 3,5-<span class="html-italic">O</span>-dicaffeoylquinic acid (3,5-diCQA) (<b>9</b>); 1,5-<span class="html-italic">O</span>-dicaffeoylquinic acid (1,5-diCQA) (<b>10</b>); 4,5-<span class="html-italic">O</span>-dicaffeoylquinic acid (4,5-diCQA) (<b>11</b>); dicaffeoylquinic acid (di-CQA) (<b>12</b>); tricaffeoylquinic acid 1 (tri-CQA 1) (<b>13</b>); tricaffeoylquinic acid 2 (tri-CQA 2) (<b>14</b>).</p> Full article ">Figure 2
<p>Structures of the phenolic compounds identified in <span class="html-italic">R. carthamoides</span> shoots 3-<span class="html-italic">O</span>-caffeoylquinic acid (3-CQA) (<b>1</b>); 5-<span class="html-italic">O</span>-caffeoylquinic acid (5-CQA, chlorogenic acid) (<b>2</b>); 4-<span class="html-italic">O</span>-caffeoylquinic acid (4-CQA) (<b>3</b>); 3,4-<span class="html-italic">O</span>-dicaffeoylquinic acid (3,4-diCQA) (<b>8</b>); 3,5-<span class="html-italic">O</span>-dicaffeoylquinic acid (3,5-diCQA) (<b>9</b>); 1,5-<span class="html-italic">O</span>-dicaffeoylquinic acid (1,5-diCQA) (<b>10</b>); 4,5-<span class="html-italic">O</span>-dicaffeoylquinic acid (4,5-diCQA) (<b>11</b>).</p> Full article ">Figure 3
<p>Effect of the LED light conditions on the content of mono-CQAs (<b>a</b>), di-CQAs (<b>b</b>), tri-CQAs (<b>c</b>), and flavonoid monoglycosides (<b>d</b>) in <span class="html-italic">R. carthamoides</span> shoots cultured for 35 days on an agar (0.7%) and the liquid-agitated MS medium supplemented with IAA 0.1 mg/L and BA 0.5 mg/L. The results are means values ± SE. There is no difference (<span class="html-italic">p</span> &lt; 0.05) among the means marked with the same letter. Control—cool-white fluorescent light (FL); WL—white LED light; BL—blue LED light; RL—red LED light; R:BL—red and blue LED (7:3) light; agar—shoots grown on agar (0.7%) MS medium; liquid—shoots grown in liquid MS medium, in a 300 mL Erlenmeyer flask on a rotary shaker at 80 rpm; agar P1—shoots grown on agar (0.7%) MS medium directly exposed to LED lights; agar pre-P5—shoots grown on agar (0.7%) MS medium exposed to LED lights for 5 passages (35 days of each).</p> Full article ">Figure 4
<p>Effect of the LED light conditions on the content of individual mono-CQAs in <span class="html-italic">R. carthamoides</span> shoots cultured for 35 days on an agar (0.7%) and in the liquid-agitated MS medium supplemented with IAA 0.1 mg/L and BA 0.5 mg/L. The results are means values ± SE. There is no difference (<span class="html-italic">p</span> &lt; 0.05) among the means for the same metabolite marked with the same letter. The compound codes refer to those applied below <a href="#molecules-29-02145-f001" class="html-fig">Figure 1</a>. Abbreviations refer to the conditions of the conducted analysis, as indicated below <a href="#molecules-29-02145-f003" class="html-fig">Figure 3</a>.</p> Full article ">Figure 5
<p>Effect of the LED light conditions on the content of individual di-CQAs in <span class="html-italic">R. carthamoides</span> shoots cultured for 35 days on an agar (0.7%) and in the liquid-agitated MS medium supplemented with IAA 0.1 mg/L and BA 0.5 mg/L. The results are means values ± SE. There is no difference (<span class="html-italic">p</span> &lt; 0.05) among the means for the same metabolite marked with the same letter. The compound codes refer to those applied below <a href="#molecules-29-02145-f001" class="html-fig">Figure 1</a>. Abbreviations refer to the conditions of the conducted analysis, as indicated below <a href="#molecules-29-02145-f003" class="html-fig">Figure 3</a>.</p> Full article ">Figure 6
<p>Effect of the LED light conditions on the content of individual tri-CQAs in <span class="html-italic">R. carthamoides</span> shoots cultured for 35 days on an agar (0.7%) and in the liquid-agitated MS medium supplemented with IAA 0.1 mg/L and BA 0.5 mg/L. The results are means values ± SE. There is no difference (<span class="html-italic">p</span> &lt; 0.05) among the means for the same metabolite marked with the same letter. The compound codes refer to those applied below <a href="#molecules-29-02145-f001" class="html-fig">Figure 1</a>. Abbreviations refer to the conditions of the conducted analysis, as indicated below <a href="#molecules-29-02145-f003" class="html-fig">Figure 3</a>. 1,4,5-triCQA—1,4,5-<span class="html-italic">O</span>-tricaffeoylquinic acid.</p> Full article ">Figure 7
<p>Heat map visualization of CQA and flavonoid productivity (mg/L). The color intensity of boxes indicates the level of specialized metabolites; darker green color presents high content while yellow colors present a low content (<b>a</b>). Productivity of CQAs and flavonoids expressed as a level above (green color) or below (yellow color) control (fluorescent light) (<b>b</b>). Abbreviations refer to the conditions of the conducted analysis, as indicated below <a href="#molecules-29-02145-f003" class="html-fig">Figure 3</a>. The compound codes refer to those applied below <a href="#molecules-29-02145-f001" class="html-fig">Figure 1</a>.</p> Full article ">Figure 8
<p><span class="html-italic">R. carthamoides</span> shoots cultured for 35 days on an agar (0.7%) solidified and in the liquid, agitated MS medium under various light conditions: control—cool-white fluorescent light (WFL), WL—white LED light, BL—blue LED light, RL—red LED light, R:BL—red and blue (70%:30%) LED light (<b>a</b>). The shoots multiplied in the liquid-agitated MS medium under BL light for 35 days (<b>b</b>). The media were supplemented with IAA 0.1 mg/L and BA 0.5 mg/L. Bar = 1 cm.</p> Full article ">Figure 9
<p>The effect of LED light conditions on the growth of <span class="html-italic">R. carthamoides</span> shoots: (<b>a</b>) proliferation rate; (<b>b</b>) fresh weight (FW) (g/shoot); (<b>c</b>) dry weight (DW) (g/shoot). The results are mean values ± SE. There is no difference (<span class="html-italic">p</span> &lt; 0.05) among the means marked with the same letter. Abbreviations refer to the conditions of the conducted analysis, as indicated below <a href="#molecules-29-02145-f003" class="html-fig">Figure 3</a>.</p> Full article ">Figure 10
<p>Relative spectral characteristics of light emitted by blue (BL) LED, red (RL) LED, blue + red (R:BL) (70%:30%) LED, white (WL) LED, and control fluorescent lamps (FL).</p> Full article ">
19 pages, 3188 KiB  
Article
meso-Tetrahexyl-7,8-dihydroxychlorin and Its Conversion to ß-Modified Derivatives
by Daniel Aicher, Dinusha Damunupola, Christian B. W. Stark, Arno Wiehe and Christian Brückner
Molecules 2024, 29(9), 2144; https://doi.org/10.3390/molecules29092144 - 5 May 2024
Viewed by 1219
Abstract
meso-Tetrahexylporphyrin was converted to its corresponding 7,8-dihydroxychlorin using an osmium tetroxide-mediated dihydroxylation strategy. Its diol moiety was shown to be able to undergo a number of subsequent oxidation reactions to form a chlorin dione and porpholactone, the first meso-alkylporphyrin-based porphyrinoid containing [...] Read more.
meso-Tetrahexylporphyrin was converted to its corresponding 7,8-dihydroxychlorin using an osmium tetroxide-mediated dihydroxylation strategy. Its diol moiety was shown to be able to undergo a number of subsequent oxidation reactions to form a chlorin dione and porpholactone, the first meso-alkylporphyrin-based porphyrinoid containing a non-pyrrolic building block. Further, the diol chlorin was shown to be susceptible to dehydration, forming the porphyrin enol that is in equilibrium with its keto-chlorin form. The meso-hexylchlorin dione could be reduced and it underwent mono- and bis-methylation reactions using methyl-Grignard reagents, and trifluoromethylation using the Ruppert-Prakash reagent. The optical and spectroscopic properties of the products are discussed and contrasted to their corresponding meso-aryl derivatives (where known). This contribution establishes meso-tetrahexyl-7,8-dihydroxychlorins as a new and versatile class of chlorins that is susceptible to a broad range of conversions to generate functionalized chlorins and a pyrrole-modified chlorin analogue. Full article
(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application, 2nd Edition)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>General structure of <span class="html-italic">meso</span>-tetraalkylporphyrins <b>5</b> and literature-known [<span class="html-italic">meso</span>-tetramethylchlorinato]nickel(II) (<b>6</b>).</p> Full article ">Figure 2
<p>UV–vis spectrum of the compounds indicated (CH<sub>2</sub>Cl<sub>2</sub>).</p> Full article ">Figure 3
<p>Stacked, normalized UV–vis spectra of the compounds indicated (CH<sub>2</sub>Cl<sub>2</sub>).</p> Full article ">Figure 4
<p>Illustrated partial <sup>1</sup>H,<sup>13</sup>C-HMBC NMR spectrum observed for dihexylporpholactone isomer <b>16A</b>.</p> Full article ">Figure 5
<p>UV–vis spectra of the compounds indicated (CH<sub>2</sub>Cl<sub>2</sub>).</p> Full article ">Scheme 1
<p>The osmium tetroxide-mediated dihydroxylation of β-alkyl- (<b>1</b>) and <span class="html-italic">meso</span>-arylporphyrins (<b>3</b>) to generate the corresponding dihydroxychlorins <b>2</b> and <b>4</b>, respectively.</p> Full article ">Scheme 2
<p>Dihydroxylation of <span class="html-italic">meso</span>-tetrahexylporphyrin <b>7</b> to produce the corresponding dihydroxychlorin <b>8</b> and tetrahydroxybacteriochlorin <b>9</b>.</p> Full article ">Scheme 3
<p>Functional group transformations of <span class="html-italic">meso</span>-tetrahexyl-2,3-dihydroxychlorin <b>8</b>.</p> Full article ">Scheme 4
<p>One-step oxidative transformations of <span class="html-italic">meso</span>-tetrahexylporphyrin <b>7</b>.</p> Full article ">Scheme 5
<p>Direct CTAP oxidation of <span class="html-italic">meso</span>-5,15-dihexylporphyrin <b>15</b>.</p> Full article ">Scheme 6
<p>Transformations of <span class="html-italic">meso</span>-tetrahexylporphyrin-7,8-dione <b>10</b>.</p> Full article ">
11 pages, 1102 KiB  
Article
Isolation and Structure Determination of New Pyrones from Dictyostelium spp. Cellular Slime Molds Coincubated with Pseudomonas spp.
by Takehiro Nishimura, Takuya Murotani, Hitomi Sasaki, Yoshinori Uekusa, Hiromi Eguchi, Hirotaka Ishigaki, Katsunori Takahashi, Yuzuru Kubohara and Haruhisa Kikuchi
Molecules 2024, 29(9), 2143; https://doi.org/10.3390/molecules29092143 - 5 May 2024
Viewed by 1206
Abstract
Cellular slime molds are excellent model organisms in the field of cell and developmental biology because of their simple developmental patterns. During our studies on the identification of bioactive molecules from secondary metabolites of cellular slime molds toward the development of novel pharmaceuticals, [...] Read more.
Cellular slime molds are excellent model organisms in the field of cell and developmental biology because of their simple developmental patterns. During our studies on the identification of bioactive molecules from secondary metabolites of cellular slime molds toward the development of novel pharmaceuticals, we revealed the structural diversity of secondary metabolites. Cellular slime molds grow by feeding on bacteria, such as Klebsiella aerogenes and Escherichia coli, without using medium components. Although changing the feeding bacteria is expected to affect dramatically the secondary metabolite production, the effect of the feeding bacteria on the production of secondary metabolites is not known. Herein, we report the isolation and structure elucidation of clavapyrone (1) from Dictyostelium clavatum, intermedipyrone (2) from D. magnum, and magnumiol (3) from D. intermedium. These compounds are not obtained from usual cultural conditions with Klebsiella aerogenes but obtained from coincubated conditions with Pseudomonas spp. The results demonstrate the diversity of the secondary metabolites of cellular slime molds and suggest that widening the range of feeding bacteria for cellular slime molds would increase their application potential in drug discovery. Full article
(This article belongs to the Special Issue Discovery of Bioactive Ingredients from Natural Products, 5th Edition)
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<p>Structures of clavapyrone (<b>1</b>), intermedipyrone (<b>2</b>), and magnumiol (<b>3</b>).</p> Full article ">Figure 2
<p>Structure of <b>1</b> and representative <sup>1</sup>H–<sup>1</sup>H COSY and HMBC correlations.</p> Full article ">Figure 3
<p>Structure of <b>2</b> and representative <sup>1</sup>H–<sup>1</sup>H COSY and HMBC correlations.</p> Full article ">Figure 4
<p>Structure of <b>3</b> and representative <sup>1</sup>H–<sup>1</sup>H COSY and HMBC correlations.</p> Full article ">Figure 5
<p>Antiproliferative activity of <b>1</b> against K562 cells.</p> Full article ">
12 pages, 5673 KiB  
Article
Deposition of Pd, Pt, and PdPt Nanoparticles on TiO2 Powder Using Supercritical Fluid Reactive Deposition: Application in the Direct Synthesis of H2O2
by Marlene Crone, Laura L. Trinkies, Roland Dittmeyer and Michael Türk
Molecules 2024, 29(9), 2142; https://doi.org/10.3390/molecules29092142 - 5 May 2024
Viewed by 1324
Abstract
In this study, we investigated the catalytic properties of mono- and bimetallic palladium (Pd) and platinum (Pt) nanoparticles deposited via supercritical fluid reactive deposition (SFRD) on titanium dioxide (TiO2) powder. Transmission electron microscopy analyses verified that SFRD experiments performed at 353 [...] Read more.
In this study, we investigated the catalytic properties of mono- and bimetallic palladium (Pd) and platinum (Pt) nanoparticles deposited via supercritical fluid reactive deposition (SFRD) on titanium dioxide (TiO2) powder. Transmission electron microscopy analyses verified that SFRD experiments performed at 353 K and 15.6 MPa enabled the deposition of uniform mono- and bimetallic nanoparticles smaller than 3 nm on TiO2. Electron-dispersive X-ray spectroscopy demonstrated the formation of alloy-type structures for the bimetallic PdPt nanoparticles. H2O2 is an excellent oxidizing reagent for the production of fine and bulk chemicals. However, until today, the design and preparation of catalysts with high H2O2 selectivity and productivity remain a great challenge. The focus of this study was on answering the questions of (a) whether the catalysts produced are suitable for the direct synthesis of hydrogen peroxide (H2O2) in the liquid phase and (b) how the metal type affects the catalytic properties. It was found that the metal type (Pd or Pt) influenced the catalytic performance strongly; the mean productivity of the mono- and bimetallic catalysts decreased in the following order: Pd > PdPt > Pt. Furthermore, all catalysts prepared by SFRD showed a significantly higher mean productivity compared to the catalyst prepared by incipient wetness impregnation. Full article
(This article belongs to the Special Issue Processing of Materials by Supercritical Fluids—Part II)
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<p>Principle of the synthesis of supported NPs by SFRD using scCO<sub>2</sub> as a solvent and as a reaction and separation medium.</p> Full article ">Figure 2
<p>Representative high-angle annular dark-field TEM images of CAT-Pd1 (<b>a</b>), CAT-Pt (<b>b</b>), CAT-Pd2 (<b>c</b>), CAT-Pd3-IWI (<b>d</b>), and CAT-Pd1Pt (<b>e</b>) and the corresponding EDXS image (<b>f</b>).</p> Full article ">Figure 3
<p>PSD and PS frequencies of Pd1 and Pd2 (<b>a</b>,<b>b</b>), Pd1 and Pt (<b>c</b>,<b>d</b>), and Pd1Pt and Pd3-IWI (<b>e</b>,<b>f</b>).</p> Full article ">Figure 4
<p>Productivities calculated and plotted over time for the different catalysts investigated (<b>a</b>) and mean productivities for the different catalysts evaluated (<b>b</b>).</p> Full article ">Figure 5
<p>Scheme of the SFRD apparatus (BD = bursting disk, PI = pressure indicator, TI = temperature indicator).</p> Full article ">
14 pages, 3404 KiB  
Article
Exploring the Influence of Cation and Halide Substitution in the Structure and Optical Properties of CH3NH3NiCl3 Perovskite
by Natalí Navarro, Ronald Nelson, Karem Gallardo and Rodrigo Castillo
Molecules 2024, 29(9), 2141; https://doi.org/10.3390/molecules29092141 - 5 May 2024
Cited by 1 | Viewed by 1280
Abstract
This manuscript details a comprehensive investigation into the synthesis, structural characterization, thermal stability, and optical properties of nickel-containing hybrid perovskites, namely CH3NH3NiCl3, CsNiCl3, and CH3NH3NiBrCl2. The focal point of [...] Read more.
This manuscript details a comprehensive investigation into the synthesis, structural characterization, thermal stability, and optical properties of nickel-containing hybrid perovskites, namely CH3NH3NiCl3, CsNiCl3, and CH3NH3NiBrCl2. The focal point of this study is to unravel the intricate crystal structures, thermal behaviors, and optical characteristics of these materials, thereby elucidating their potential application in energy conversion and storage technologies. X-ray powder diffraction measurements confirm that CH3NH3NiCl3 adopts a crystal structure within the Cmcm space group, while CsNiCl3 is organized in the P63/mmc space group, as reported previously. Such structural diversity underscores the complex nature of these perovskites and their potential for tailored applications. Thermal analysis further reveals the stability of CH3NH3NiCl3 and CH3NH3NiBrCl2, which begin to decompose at 260 °C and 295 °C, respectively. The optical absorption properties of these perovskites studied by UV-VIS-NIR spectroscopy revealed the bands characteristic of Ni2+ ions in an octahedral environment. Notably, these absorption bands exhibit subtle shifts upon bromide substitution, suggesting that optical properties can be finely tuned through halide modification. Such tunability is paramount for the design and development of materials with specific optical requirements. By offering a detailed examination of these properties, the study lays the groundwork for future advancements in material science, particularly in the development of innovative materials for sustainable energy technologies. Full article
(This article belongs to the Section Inorganic Chemistry)
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Figure 1
<p>X-ray powder diffraction patterns of samples of mixed samples of composition (MA)<sub>1−x</sub>Cs<sub>x</sub>NiCl<sub>3</sub>, and references patterns for CsNiCl<sub>3</sub> and (MA)NiCl<sub>3</sub>.</p> Full article ">Figure 2
<p>Selected diffraction peaks corresponding to the MANiCl<sub>3</sub> and CsNiCl<sub>3</sub> phases, demonstrating discrete shifts with increasing concentrations of Cs<sup>+</sup> and MA<sup>+</sup> ions, respectively.</p> Full article ">Figure 3
<p>X-ray powder diffraction patterns of samples (MA)NiCl<sub>3</sub> and (MA)NiBrCl<sub>2</sub>.</p> Full article ">Figure 4
<p>Thermogravimetric (<b>top</b>) and differential scanning calorimetry (<b>bottom</b>) analysis of samples CsNiCl<sub>3</sub>, (MA)NiCl<sub>3</sub>, and (MA)NiBrCl<sub>2</sub>.</p> Full article ">Figure 5
<p>SEM micrograph with EDS mapping of the product after thermal analysis (<b>top</b>) and the EDX spectra (<b>bottom</b>). Red, green, and cyan correspond to the elements Ni, Cl, and Br, respectively.</p> Full article ">Figure 6
<p>Thermogravimetric behavior of samples (MA)<sub>1−x</sub>CsNiCl<sub>3</sub> (x = 0.0; 0.2; 0.4; 0.6; 0.8; and 1.0).</p> Full article ">Figure 7
<p>Raman spectra of (MA)<sub>x</sub>Cs<sub>1−x</sub>NiCl<sub>3</sub> samples measured at room temperature. The ν1–ν15 modes are indicated in <a href="#molecules-29-02141-t002" class="html-table">Table 2</a>.</p> Full article ">Figure 8
<p>Raman spectra of samples (MA)NiCl<sub>3</sub>, (MA)NiBrCl<sub>2</sub>, and CsNiCl<sub>3</sub>, detailed in the three characteristic zones of hybrid perovskites.</p> Full article ">Figure 9
<p>UV-VIS-NIR absorption spectra of samples (MA)NiCl<sub>3</sub>, CsNiCl<sub>3</sub>, and (MA)NiBrCl<sub>2</sub>.</p> Full article ">
16 pages, 3551 KiB  
Article
Human Plasma Butyrylcholinesterase Hydrolyzes Atropine: Kinetic and Molecular Modeling Studies
by Aliya Mukhametgalieva, Showkat Ahmad Mir, Zukhra Shaihutdinova and Patrick Masson
Molecules 2024, 29(9), 2140; https://doi.org/10.3390/molecules29092140 - 4 May 2024
Cited by 1 | Viewed by 1769
Abstract
The participation of butyrylcholinesterase (BChE) in the degradation of atropine has been recurrently addressed for more than 70 years. However, no conclusive answer has been provided for the human enzyme so far. In the present work, a steady-state kinetic analysis performed by spectrophotometry [...] Read more.
The participation of butyrylcholinesterase (BChE) in the degradation of atropine has been recurrently addressed for more than 70 years. However, no conclusive answer has been provided for the human enzyme so far. In the present work, a steady-state kinetic analysis performed by spectrophotometry showed that highly purified human plasma BChE tetramer slowly hydrolyzes atropine at pH 7.0 and 25 °C. The affinity of atropine for the enzyme is weak, and the observed kinetic rates versus the atropine concentration was of the first order: the maximum atropine concentration in essays was much less than Km. Thus, the bimolecular rate constant was found to be kcat/Km = 7.7 × 104 M−1 min−1. Rough estimates of catalytic parameters provided slow kcat < 40 min−1 and high Km = 0.3–3.3 mM. Then, using a specific organophosphoryl agent, echothiophate, the time-dependent irreversible inhibition profiles of BChE for hydrolysis of atropine and the standard substrate butyrylthiocholine (BTC) were investigated. This established that both substrates are hydrolyzed at the same site, i.e., S198, as for all substrates of this enzyme. Lastly, molecular docking provided evidence that both atropine isomers bind to the active center of BChE. However, free energy perturbations yielded by the Bennett Acceptance Ratio method suggest that the L-atropine isomer is the most reactive enantiomer. In conclusion, the results provided evidence that plasma BChE slowly hydrolyzes atropine but should have no significant role in its metabolism under current conditions of medical use and even under administration of the highest possible doses of this antimuscarinic drug. Full article
(This article belongs to the Special Issue Feature Papers in Computational and Theoretical Chemistry)
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<p>Atropine; and D and L isomers. Ester of tropic acid (3-hydroxy-2-phenylpropanoic acid) and α-tropan-3ol. C* are the chiral center.</p> Full article ">Figure 2
<p>Steady-state hydrolysis of atropine by human BChE in 0.1 M phosphate buffer, pH 7.0 at 25 °C. (<b>A</b>) Hydrolysis as a function of atropine concentration [A] (grey line, 0.025 mM; red line, 0.05 mM; blue line, 0.1 mM; pink line, 0.2 mM) using [E] = 1.7 nM. (<b>B</b>) BChE-catalyzed hydrolysis rate of [A] = 0.1 mM at increasing enzyme concentration.</p> Full article ">Figure 3
<p>(<b>A</b>) Hydrolysis rate (−dAbs/dt) of racemic atropine (mM) by human BChE ([E] = 0.17 × 10<sup>−8</sup> M; 1.7 nM) as a function of atropine concentration in 0.1 M phosphate pH 7.0 at 25 °C; r<sup>2</sup> = 0.99, slope = 0.00293 ± 0.0001. (<b>B</b>) Hydrolysis rate (−dAbs/dt) of racemic atropine ([atropine] = 0.1 mM) by different concentrations ([E]) of human BChE ranging from 0.17 nM to 5.1 nM in 0.1 M phosphate pH 7.0 at 25 °C; r<sup>2</sup> = 0.99; slope = 0.000179 ± 0.000007.</p> Full article ">Figure 4
<p>Progressive inhibition of BChE ([E] = 1.7 × 10<sup>−9</sup> M) as a function of time by echothiophate (5 × 10<sup>−8</sup> M) as monitored by the decrease in activity with 50 μM BTC (black curve) and 0.2 mM atropine (red curve) under first-order conditions ([E] &lt;&lt; K<sub>m</sub>) in 0.1 M phosphate pH 7.0 at 25 °C. [E]<sub>t,0</sub> = 100% = [E]<sub>0</sub> + [E’]<sub>0</sub>; [E’]<sub>0</sub> = 50%. Insert: Ln[E%]) versus time until t = 15 min.</p> Full article ">Figure 5
<p>Side view of the active site gorge in human BChE in which D and L atropine are complexed and represented in red and blue color. Crucial residues in the Peripheral Anionic Site (PAS) and Catalytic Anionic Site (CAS) are shown. The Ω-loop is shown in purple, and the acyl-binding pocket (ABP) loop is represented in dim green. H-bonding is observed between PAS residues Y332 and D70 (depicted in dim orange), which play a role in controlling the entrance of the active site gorge. The catalytic triad, consisting of residues S198, H438, and E325, is displayed with atoms C in cyan, N in blue, and O in red. Hydrogen bonds connect the catalytic triad residues (S198…H438…E325) and PAS residues (D70…Y332). The above image was prepared by using visual molecular dynamics software VMD 1.9a51 [<a href="#B33-molecules-29-02140" class="html-bibr">33</a>].</p> Full article ">Figure 6
<p>D-atropine interacts with the binding site of the BChE (<b>A</b>, <b>B</b> enlarged part of <b>A</b>). L-atropine interacts with amino acids in the binding site of BChE (<b>C</b>, <b>D</b> enlarged part of <b>C</b>). The color of interactions represents the type of bond formed. The interaction figures were generated by using BIOVIA Discovery Studio Visualizer Software, version 21.1.0.20298, Dassault Systems BIOVA, <a href="https://www.3dsbiovia.com/" target="_blank">https://www.3dsbiovia.com/</a> accessed on 22 January 2024.</p> Full article ">Figure 7
<p>Initial and final lambda states of D-atropine. The lambda_01 in green represents the coupled state of D-atropine, and the lambda_0 state of D-atropine, represented in red, is the decoupled state of D-atropine.</p> Full article ">Figure 8
<p>Relative free energy differences for each interval of λ (i.e., between neighboring Hamiltonians) for isomers of atropine represented in the legend box (<b>A</b>); and with the cumulative ΔG as a function of λ, the point at λ = 1 corresponds to the sum of ΔG from λ vector 0 to λ vector 1 (<b>B</b>).</p> Full article ">Scheme 1
<p>BChE-catalyzed hydrolysis scheme for low concentrations of esters.</p> Full article ">
18 pages, 3491 KiB  
Article
Ring-Opening Polymerization of Cyclohexene Oxide and Cycloaddition with CO2 Catalyzed by Amine Triphenolate Iron(III) Complexes
by Peng Li, Sixuan Li, Xin Dai, Shifeng Gao, Zhaozheng Song and Qingzhe Jiang
Molecules 2024, 29(9), 2139; https://doi.org/10.3390/molecules29092139 - 4 May 2024
Cited by 3 | Viewed by 1865
Abstract
A series of novel amine triphenolate iron complexes were synthesized and characterized using UV, IR, elemental analysis, and high-resolution mass spectrometry. These complexes were applied to the ring-opening polymerization (ROP) of cyclohexene oxide (CHO), demonstrating excellent activity (TOF > 11050 h−1) [...] Read more.
A series of novel amine triphenolate iron complexes were synthesized and characterized using UV, IR, elemental analysis, and high-resolution mass spectrometry. These complexes were applied to the ring-opening polymerization (ROP) of cyclohexene oxide (CHO), demonstrating excellent activity (TOF > 11050 h−1) in the absence of a co-catalyst. In addition, complex C1 maintained the dimer in the presence of the reaction substrate CHO, catalyzing the ring-opening polymerization of CHO to PCHO through bimetallic synergy. Furthermore, a two-component system consisting of iron complexes and TBAB displayed the ability to catalyze the reaction of CHO with CO2, resulting in the formation of cis-cyclic carbonate with high selectivity. Complex C4 exhibited the highest catalytic activity, achieving 80% conversion of CHO at a CHO/C4/TBAB molar ratio of 2000/1/8 and a CO2 pressure of 3 MPa for 16 h at 100 °C, while maintaining >99% selectivity of cis-cyclic carbonates, which demonstrated good conversion and selectivity. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous, 2nd Edition)
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<p>UV spectrum of complex C4 titrated with different equivalent CHO (<b>a</b>) and PPNCl (<b>b</b>).</p> Full article ">Figure 2
<p>Relationship between CHO conversion and time at different temperatures.</p> Full article ">Figure 3
<p>First-order ln([M]<sub>0</sub>/[M]<sub>t</sub>) vs. time plot at different temperatures.</p> Full article ">Figure 4
<p>Arlenius plot for the formation of PCHO.</p> Full article ">Figure 5
<p>Relationship between CHO conversion and time at different temperatures.</p> Full article ">Figure 6
<p>First-order ln([M]<sub>0</sub>/[M]<sub>t</sub>) vs. time plot at different temperatures.</p> Full article ">Figure 7
<p>Arlenius plot for the formation of cyclic esters.</p> Full article ">Scheme 1
<p>Synthesis roadmap of ligands and complexes.</p> Full article ">Scheme 2
<p>Ring-opening polymerization of CHO catalyzed by iron catalyst.</p> Full article ">Scheme 3
<p>Proposed mechanism for CHO ring-opening polymerization mediated by iron(III) complex.</p> Full article ">Scheme 4
<p>Cycloaddition reaction of CHO/CO<sub>2</sub>.</p> Full article ">Scheme 5
<p>Proposed mechanism of cyclic carbonate synthesis.</p> Full article ">
17 pages, 1085 KiB  
Article
Design, Synthesis and Biological Activity of Novel Methoxy- and Hydroxy-Substituted N-Benzimidazole-Derived Carboxamides
by Anja Beč, Katarina Zlatić, Mihailo Banjanac, Vedrana Radovanović, Kristina Starčević, Marijeta Kralj and Marijana Hranjec
Molecules 2024, 29(9), 2138; https://doi.org/10.3390/molecules29092138 - 4 May 2024
Cited by 2 | Viewed by 1444
Abstract
This work presents the design, synthesis and biological activity of novel N-substituted benzimidazole carboxamides bearing either a variable number of methoxy and/or hydroxy groups. The targeted carboxamides were designed to investigate the influence of the number of methoxy and/or hydroxy groups, the [...] Read more.
This work presents the design, synthesis and biological activity of novel N-substituted benzimidazole carboxamides bearing either a variable number of methoxy and/or hydroxy groups. The targeted carboxamides were designed to investigate the influence of the number of methoxy and/or hydroxy groups, the type of substituent placed on the N atom of the benzimidazole core and the type of substituent placed on the benzimidazole core on biological activity. The most promising derivatives with pronounced antiproliferative activity proved to be N-methyl-substituted derivatives with hydroxyl and methoxy groups at the phenyl ring and cyano groups on the benzimidazole nuclei with selective activity against the MCF-7 cell line (IC50 = 3.1 μM). In addition, the cyano-substituted derivatives 10 and 11 showed strong antiproliferative activity against the tested cells (IC50 = 1.2–5.3 μM). Several tested compounds showed significantly improved antioxidative activity in all three methods compared to standard BHT. In addition, the antioxidative activity of 9, 10, 32 and 36 in the cells generally confirmed their antioxidant ability demonstrated in vitro. However, their antiproliferative activity was not related to their ability to inhibit oxidative stress nor to their ability to induce it. Compound 8 with two hydroxy and one methoxy group on the phenyl ring showed the strongest antibacterial activity against the Gram-positive strain E. faecalis (MIC = 8 μM). Full article
(This article belongs to the Special Issue Heterocycles in Medicinal Chemistry II)
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<p>Previously synthesized <span class="html-italic">N</span>-substituted benzimidazole derived benzamides <b>I</b> and <b>II</b>.</p> Full article ">Figure 2
<p>Antioxidative activity of selected systems. HCT 116 cells were treated with a combination of H<sub>2</sub>O<sub>2</sub> (4 mM) and <span class="html-italic">N</span>-acetyl-<span class="html-italic">L</span>-cysteine (NAC, 10 mM) or the tested compounds (10 mM). Treatment with H<sub>2</sub>O<sub>2</sub> (4 mM) alone was used as a control for ROS induction. The level of reactive oxygen species (ROS) was measured with the fluorescent dye DCFH-DA using a fluorimeter. The data presented here are the results of three independent measurements carried out in triplicate. A one-way ANOVA with Tukey’s post hoc test was used for statistical analysis, *** <span class="html-italic">p</span> &lt; 0.001; ns—not significant.</p> Full article ">Scheme 1
<p>Synthesis of benzimidazole-derived benzamides <b>7</b>–<b>12</b>.</p> Full article ">Scheme 2
<p>Synthesis of benzimidazole-derived benzamides <b>24</b>–<b>37</b>.</p> Full article ">
17 pages, 4032 KiB  
Article
Pioglitazone Phases and Metabolic Effects in Nanoparticle-Treated Cells Analyzed via Rapid Visualization of FLIM Images
by Biagio Todaro, Luca Pesce, Francesco Cardarelli and Stefano Luin
Molecules 2024, 29(9), 2137; https://doi.org/10.3390/molecules29092137 - 4 May 2024
Viewed by 4638
Abstract
Fluorescence lifetime imaging microscopy (FLIM) has proven to be a useful method for analyzing various aspects of material science and biology, like the supramolecular organization of (slightly) fluorescent compounds or the metabolic activity in non-labeled cells; in particular, FLIM phasor analysis (phasor-FLIM) has [...] Read more.
Fluorescence lifetime imaging microscopy (FLIM) has proven to be a useful method for analyzing various aspects of material science and biology, like the supramolecular organization of (slightly) fluorescent compounds or the metabolic activity in non-labeled cells; in particular, FLIM phasor analysis (phasor-FLIM) has the potential for an intuitive representation of complex fluorescence decays and therefore of the analyzed properties. Here we present and make available tools to fully exploit this potential, in particular by coding via hue, saturation, and intensity the phasor positions and their weights both in the phasor plot and in the microscope image. We apply these tools to analyze FLIM data acquired via two-photon microscopy to visualize: (i) different phases of the drug pioglitazone (PGZ) in solutions and/or crystals, (ii) the position in the phasor plot of non-labelled poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), and (iii) the effect of PGZ or PGZ-containing NPs on the metabolism of insulinoma (INS-1 E) model cells. PGZ is recognized for its efficacy in addressing insulin resistance and hyperglycemia in type 2 diabetes mellitus, and polymeric nanoparticles offer versatile platforms for drug delivery due to their biocompatibility and controlled release kinetics. This study lays the foundation for a better understanding via phasor-FLIM of the organization and effects of drugs, in particular, PGZ, within NPs, aiming at better control of encapsulation and pharmacokinetics, and potentially at novel anti-diabetics theragnostic nanotools. Full article
(This article belongs to the Special Issue Nanostructured Materials: Synthesis, Functionalization and Applications in Biomedicine)
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<p>Characterization of free PGZ using FLIM. For each panel, on the left are reported the FLIM images and on the right the phasor plots (with corresponding colors): (<b>A</b>) PGZ solid, (<b>B</b>) PGZ in DMF at 37 °C at time 0, (<b>C</b>) PGZ in DMF at 37 °C at 20 min, (<b>D</b>) at 30 min, (<b>E</b>) at 50 min, and (<b>F</b>) at 55 min in a different position; in the phasor plot, vertices of the triangle correspond to the “principal” points, and the “center” point, where the saturation is 0 (see <a href="#sec3-molecules-29-02137" class="html-sec">Section 3</a> and <a href="#sec4dot5-molecules-29-02137" class="html-sec">Section 4.5</a>) is shown in cyan. For all the panels: on top, figures with a linear intensity scale (normalized to maximum); on the bottom, the same figures with a logarithmic intensity scale starting from a 0.01 fraction of the maximum intensity in the image; on the right these intensity scales are shown in corresponding positions for various values of hue and saturation. Note how the evaporation of DMF with time causes the formation of PGZ crystals, and that the used color coding based on the position of the phasor plot for each pixel allows appreciating at a glance the different forms of PGZ and their position within the images. The side of the square microscopy image is 106 µm here and in all the following figures.</p> Full article ">Figure 2
<p>Characterization of empty PLGA nanoparticles and PGZ-loaded PLGA NPs using FLIM. For each panel, on the left are reported the FLIM images and on the right the phasor plots (with corresponding colors) for exemplary cases for NPs (<b>A</b>–<b>D</b>) and for solid PLGA (<b>E</b>): (<b>A</b>) empty PLGA NPs in RPMI, (<b>B</b>) PGZ-loaded PLGA NPs in RPMI, (<b>C</b>) empty PLGA NPs in PBS, (<b>D</b>) PGZ-loaded PLGA NPs in PBS, (<b>E</b>) solid PLGA. A linear scale was used for the intensity normalized to the maximum in each picture (like on top in <a href="#molecules-29-02137-f001" class="html-fig">Figure 1</a>; color scale reported in panel (<b>F</b>)). Two color codes were used, one like in <a href="#molecules-29-02137-f001" class="html-fig">Figure 1</a> (top figures in each panel), one with additional principal points (see main text), as shown in the right bottom figure in each panel (vertices of the polygon and light gray crosses), with hue of 0/1 at (0,0) and increasing clockwise, and a “center” point (cyan ×) inside but towards the bottom of the polygon.</p> Full article ">Figure 3
<p>FLIM of PGZ and of INS-1E cells in RPMI medium, also upon co-incubation and incubation with nanoparticles for 24 h at 37 °C. (<b>A</b>) RPMI, (<b>B</b>) PGZ in RPMI, (<b>C</b>) INS-1E in RPMI, (<b>D</b>) INS-1E in RPMI in the presence of 0.1 mg/mL PGZ, (<b>E</b>) INS-1E in RPMI in presence of empty PLGA NPs, (<b>F</b>) INS-1E in RPMI in presence of PGZ-loaded PLGA NPs. Each panel has the same composition, color coding, and intensity scales as in <a href="#molecules-29-02137-f001" class="html-fig">Figure 1</a> (and in the top parts of the panels in <a href="#molecules-29-02137-f002" class="html-fig">Figure 2</a> for the linear intensity scale), in order to compare more easily the results and to show at-a-glance possible signals arising from the species observed in the previous cases.</p> Full article ">Figure 4
<p>FLIM characterization of INS-1E cells interacting with PGZ and with the nanoparticles considered in this work. The same data of <a href="#molecules-29-02137-f003" class="html-fig">Figure 3</a>C–F are here reported with a different color encoding for phasor position (principal points at the vertices of the triangle and center point in cyan in the right part of each panel), in order to better appreciate the position of phasors characterizing fluorescence arising from within the cells. (<b>A</b>) INS-1E in RPMI, (<b>B</b>) INS-1E in RPMI in the presence of PGZ, (<b>C</b>) INS-1E in RPMI in the presence of empty PLGA NPs, (<b>D</b>) INS-1E in RPMI in the presence of PGZ-loaded PLGA NPs. For each panel: on the left, FLIM images; on the right, phasor plots with corresponding colors; on the top, a linear intensity scale is used (the most on the left on the top of the figure), on the bottom a logarithmic one starting from 1% (panels (<b>A</b>,<b>C</b>,<b>D</b>), center color scale on top of the figure) or from 0.5% (panel (<b>B</b>), rightmost color scale on the top of the figure) of the maximum intensity in each image. Note that, on average, the apparent intensities of cells in the bottom image of panel (<b>B</b>) are similar to the ones on the top images in the other panels.</p> Full article ">
10 pages, 1044 KiB  
Article
Asymmetric Synthesis of Three Alkenyl Epoxides: Crafting the Sex Pheromones of the Elm Spanworm and the Painted Apple Moth
by Yun Zhou, Jianan Wang, Beijing Tian, Yanwei Zhu, Yujuan Zhang, Jinlong Han, Jiangchun Zhong and Chenggang Shan
Molecules 2024, 29(9), 2136; https://doi.org/10.3390/molecules29092136 - 4 May 2024
Viewed by 1424
Abstract
A concise synthesis of the sex pheromones of elm spanworm as well as painted apple moth has been achieved. The key steps were the alkylation of acetylide ion, Sharpless asymmetric epoxidation and Brown’s P2-Ni reduction. This approach provided the sex pheromone of the [...] Read more.
A concise synthesis of the sex pheromones of elm spanworm as well as painted apple moth has been achieved. The key steps were the alkylation of acetylide ion, Sharpless asymmetric epoxidation and Brown’s P2-Ni reduction. This approach provided the sex pheromone of the elm spanworm (1) in 31% total yield and those of the painted apple moth (2, 3) in 26% and 32% total yields. The ee values of three final products were up to 99%. The synthesized pheromones hold promising potential for use in the management and control of these pests. Full article
(This article belongs to the Section Organic Chemistry)
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<p>The sex pheromones of the elm spanworm and the painted apple moth.</p> Full article ">Scheme 1
<p>Retrosynthetic analysis of the sex pheromone <b>1</b>.</p> Full article ">Scheme 2
<p>Synthesis of chiral epoxy alcohols <b>14</b>–<b>16</b>.</p> Full article ">Scheme 3
<p>Synthesis of target compounds <b>1</b>, <b>2</b> and <b>3</b>.</p> Full article ">
27 pages, 11580 KiB  
Article
Exploring the Efficiency of Algerian Kaolinite Clay in the Adsorption of Cr(III) from Aqueous Solutions: Experimental and Computational Insights
by Karima Rouibah, Hana Ferkous, Meniai Abdessalam-Hassan, Bencheikh Lehocine Mossab, Abir Boublia, Christel Pierlot, Amdjed Abdennouri, Ivalina Avramova, Manawwer Alam, Yacine Benguerba and Alessandro Erto
Molecules 2024, 29(9), 2135; https://doi.org/10.3390/molecules29092135 - 4 May 2024
Cited by 23 | Viewed by 1733
Abstract
The current study comprehensively investigates the adsorption behavior of chromium (Cr(III)) in wastewater using Algerian kaolinite clay. The structural and textural properties of the kaolinite clay are extensively characterized through a range of analytical methods, including XRD, FTIR, SEM-EDS, XPS, laser granulometry, N [...] Read more.
The current study comprehensively investigates the adsorption behavior of chromium (Cr(III)) in wastewater using Algerian kaolinite clay. The structural and textural properties of the kaolinite clay are extensively characterized through a range of analytical methods, including XRD, FTIR, SEM-EDS, XPS, laser granulometry, N2 adsorption isotherm, and TGA–DTA. The point of zero charge and zeta potential are also assessed. Chromium adsorption reached equilibrium within five minutes, achieving a maximum removal rate of 99% at pH 5. Adsorption equilibrium is modeled using the Langmuir, Freundlich, Temkin, Elovich, and Dubinin–Radushkevitch equations, with the Langmuir isotherm accurately describing the adsorption process and yielding a maximum adsorption capacity of 8.422 mg/g for Cr(III). Thermodynamic parameters suggest the spontaneous and endothermic nature of Cr(III) sorption, with an activation energy of 26.665 kJ/mol, indicating the importance of diffusion in the sorption process. Furthermore, advanced DFT computations, including COSMO-RS, molecular orbitals, IGM, RDG, and QTAIM analyses, are conducted to elucidate the nature of adsorption, revealing strong binding interactions between Cr(III) ions and the kaolinite surface. The integration of theoretical and experimental data not only enhances the understanding of Cr(III) removal using kaolinite but also demonstrates the effectiveness of this clay adsorbent for wastewater treatment. Furthermore, this study highlights the synergistic application of empirical research and computational modeling in elucidating complex adsorption processes. Full article
(This article belongs to the Special Issue Novel Adsorbents for Organic Pollutants Elimination from Aqueous Matrixes)
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<p>Structural characterization of kaolin: X-ray diffraction patterns of kaolin (<b>a</b>) and FTIR spectrum of kaolin after and before Cr<sup>3+</sup> adsorption (<b>b</b>,<b>c</b>).</p> Full article ">Figure 2
<p>SEM images of kaolin at magnifications ×10.00 (<b>a</b>), ×5.00 (<b>b</b>,<b>c</b>), and ×2.00 µm (<b>d</b>).</p> Full article ">Figure 2 Cont.
<p>SEM images of kaolin at magnifications ×10.00 (<b>a</b>), ×5.00 (<b>b</b>,<b>c</b>), and ×2.00 µm (<b>d</b>).</p> Full article ">Figure 3
<p>Kaolin EDS microanalysis.</p> Full article ">Figure 4
<p>Particle size distribution of kaolin: (<b>a</b>) focal distance of 300 mm and (<b>b</b>) focal distance of 45 mm.</p> Full article ">Figure 5
<p>XPS survey spectra of kaolin.</p> Full article ">Figure 6
<p>High resolution of XPS spectra of (<b>a</b>) Al 2p, (<b>b</b>) Si 2p, (<b>c</b>) O 1s, and (<b>d</b>) C 1s.</p> Full article ">Figure 7
<p>N<sub>2</sub> adsorption–desorption and pore size distribution.</p> Full article ">Figure 8
<p>TGA–DTA curves of kaolin.</p> Full article ">Figure 9
<p>(<b>a</b>) Kaolin point of zero charge measurement and (<b>b</b>) zeta potential values of kaolin as a function of pH.</p> Full article ">Figure 10
<p>Effect of the contact time (<b>a</b>) and initial concentration (<b>b</b>) on the adsorption capacity of the adsorbent under constant conditions: pH = 5, T = 22 °C, V = 300 rpm, and r = 10 g/L.</p> Full article ">Figure 11
<p>Effect of (<b>a</b>) pH and (<b>b</b>) solid–liquid ratio on the removal percentage of Cr(III) under constant conditions: C<sub>0</sub> = 10 mg/L, T = 22 °C, t<sub>c</sub> = 120 min, V = 300 rpm, and r = 10 g/L.</p> Full article ">Figure 12
<p>Ionic strength’s effect on the adsorption capacity of adsorbent under constant conditions: pH = 5, T = 22 °C, V = 300 rpm, and r = 10 g/L.</p> Full article ">Figure 13
<p>(<b>a</b>) Temperature’s effect for the conditions C<sub>0</sub> = 10 mg/L, pH = 5, V = 300 rpm, and r = 10 g/L and (<b>b</b>) variation of the adsorption constant of Cr(III) as a function of temperature.</p> Full article ">Figure 14
<p>Adsorption isotherm of Cr(III) on kaolin with the conditions V = 300 rpm, pH = 5, T = 22 °C, and r = 10 g/L.</p> Full article ">Figure 15
<p>Detailed description with side and top views for the structure model of the kaolinite surface.</p> Full article ">Figure 16
<p>Detailed description of the COSMO-RS distribution with side and top views for the adsorbed Cr(OH)<sub>3</sub> onto kaolinite surface in Al–O(H) (<b>a</b>) and Si–O (<b>b</b>) layers.</p> Full article ">Figure 17
<p>Frontier orbital distributions of the structure models for the adsorbed Cr(OH)<sub>3</sub> onto kaolinite surface in Al–O(H) (<b>a</b>) and Si–O (<b>b</b>) layers.</p> Full article ">Figure 18
<p>The visualized IGM weak interaction regions (isosurface value = 0.05 a.u.) and the RDG scatter map of the kaolinite surface attached to Cr(OH)<sub>3</sub> in Al–O(H) (<b>a</b>,<b>c</b>) and Si–O (<b>b</b>,<b>d</b>) layers.</p> Full article ">Figure 19
<p>The QTAIM maps of the kaolinite surface attached to Cr(OH)<sub>3</sub> in Si–O (<b>a</b>) and Al–O(H) (<b>b</b>) layers.</p> Full article ">
18 pages, 9765 KiB  
Article
Stress Granule Core Protein-Derived Peptides Inhibit Assembly of Stress Granules and Improve Sorafenib Sensitivity in Cancer Cells
by Juan Li, Yaobin Zhang, Jinxuan Gu, Yulin Zhou, Jie Liu, Haiyan Cui, Tiejun Zhao and Zhigang Jin
Molecules 2024, 29(9), 2134; https://doi.org/10.3390/molecules29092134 - 4 May 2024
Cited by 1 | Viewed by 2583
Abstract
Upon a variety of environmental stresses, eukaryotic cells usually recruit translational stalled mRNAs and RNA-binding proteins to form cytoplasmic condensates known as stress granules (SGs), which minimize stress-induced damage and promote stress adaptation and cell survival. SGs are hijacked by cancer cells to [...] Read more.
Upon a variety of environmental stresses, eukaryotic cells usually recruit translational stalled mRNAs and RNA-binding proteins to form cytoplasmic condensates known as stress granules (SGs), which minimize stress-induced damage and promote stress adaptation and cell survival. SGs are hijacked by cancer cells to promote cell survival and are consequently involved in the development of anticancer drug resistance. However, the design and application of chemical compounds targeting SGs to improve anticancer drug efficacy have rarely been studied. Here, we developed two types of SG inhibitory peptides (SIPs) derived from SG core proteins Caprin1 and USP10 and fused with cell-penetrating peptides to generate TAT-SIP-C1/2 and SIP-U1-Antp, respectively. We obtained 11 SG-inducing anticancer compounds from cell-based screens and explored the potential application of SIPs in overcoming resistance to the SG-inducing anticancer drug sorafenib. We found that SIPs increased the sensitivity of HeLa cells to sorafenib via the disruption of SGs. Therefore, anticancer drugs which are competent to induce SGs could be combined with SIPs to sensitize cancer cells, which might provide a novel therapeutic strategy to alleviate anticancer drug resistance. Full article
(This article belongs to the Topic Natural Bioactive Compounds as a Promising Approach to Mitigating Oxidative Stress)
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<p>Design strategy for SG core protein-derived SG inhibitory peptides. (<b>A</b>) G3BP1 protein–protein interaction network. (<b>B</b>) Co-IP showing the G3BP1 and Caprin1 interaction and G3BP1/2 dimerization. HEK293T cells were transfected with indicated expression plasmids and cell lysates were subjected to Co-IP using the anti-Flag antibody, followed by Western blot analysis. (<b>C</b>) Schematic representation of functional domains in human Caprin1, G3BP1, and USP10 indicated in different colored boxes. IDR, intrinsically disordered region; GIM, G3BP1-interacting motif; RRM, RNA recognition motif; UCH, Ubiquitin C-terminal hydrolase. (<b>D</b>) Schematic representation of design rationale for SIPs derived from SG core proteins Caprin1, G3BP1, and USP10.</p> Full article ">Figure 2
<p>Identification of Caprin1-derived SG inhibitory peptides. (<b>A</b>) Co-IP showing the interaction between G3BP1 and serial fragments of Caprin1. HEK293T cells were transfected with indicated expression plasmids and cell lysates were subjected to Co-IP using the anti-Myc antibody, followed by Western blot analysis. (<b>B,C</b>) GST pull-down showing the interaction between G3BP1 and serial fragments or internal deletions of Caprin1. HEK293T cells were transfected with indicated expression plasmids and cell lysates were subjected to GST pull-down using GST-G3BP1 beads, followed by Western blot analysis. (<b>D</b>) GST pull-down showing that Caprin1 fragment 361–385 competed with full-length Caprin1 to bind G3BP1 in a dose-dependent manner. HEK293T cells were transfected with indicated expression plasmids and cell lysates were subjected to GST pull-down using GST or GST-G3BP1 beads, followed by Western blot analysis. (<b>E</b>) Statistical analysis of the binding efficiency of full-length Caprin1 to G3BP1 shown in panel (<b>D</b>). * <span class="html-italic">p</span> ≤ 0.05.</p> Full article ">Figure 3
<p>Overexpression of Caprin1-derived fragments inhibits SG assembly. (<b>A</b>) Amino acid sequences of Caprin1 351–390 (SIP-C1) and 361–385 (SIP-C2). (<b>B</b>) Immunofluorescence showing that overexpression of Caprin1 fragments 351–390 and 361–385 inhibited AS-induced SGs. HeLa cells were transfected with indicated expression plasmids, treated with 0.5 mM AS for 45 min and subjected to immunofluorescence staining using the anti-G3BP1 antibody. Solid triangles indicate cells with SGs while empty triangles indicate cells without SGs. Scale bars: 20 µm. (<b>C</b>) Statistical analysis of SG induction efficiency shown in panel (<b>B</b>), which is reflected by the percentage of SG-positive cells among cells successfully transfected with expression plasmids. * <span class="html-italic">p</span> ≤ 0.05.</p> Full article ">Figure 4
<p>Identification of G3BP1-derived SG inhibitory peptides. (<b>A,B</b>) Co-IP showing the interaction between Caprin1 and serial fragments of G3BP1. HEK293T cells were transfected with indicated expression plasmids and cell lysates were subjected to Co-IP using the anti-Myc antibody, followed by Western blot analysis. (<b>C</b>) Immunofluorescence showing that only overexpression of G3BP1 fragment 1–141 (NTF2L) effectively inhibited AS-induced SGs. HeLa cells were transfected with indicated expression plasmids, treated with 0.5 mM AS for 45 min and subjected to immunofluorescence staining using the anti-Caprin1 antibody. Solid triangles indicate cells with SGs while empty triangles indicate cells without SGs. Scale bars: 20  µm. (<b>D</b>) Statistical analysis of SG induction efficiency shown in panel (<b>C</b>), which is reflected by the percentage of SG-positive cells among cells successfully transfected with expression plasmids. * <span class="html-italic">p</span> ≤ 0.05.</p> Full article ">Figure 5
<p>Identification of FGDF motif-containing SG inhibitory peptides derived from USP10 and viral protein nsp3. (<b>A</b>) Amino acid sequences of USP10-derived SIP (USP10-FGDF) and nsp3-derived SIPs (nsp3-FGDF1 and nsp3-FGDF2) containing FGDF motif. (<b>B</b>) Immunofluorescence showing that overexpression of FGDF motif-containing fragments USP10-FGDF, nsp3-FGDF1, and nsp3-FGDF2 effectively inhibited AS-induced SGs. HeLa cells were transfected with indicated expression plasmids, treated with 0.5 mM AS for 45 min and subjected to immunofluorescence staining using the anti-G3BP1 antibody. Empty triangles indicate cells without SGs. Scale bars: 20 µm. (<b>C</b>) Statistical analysis of SG induction efficiency shown in panel (<b>B</b>), which is reflected by the percentage of SG-positive cells among cells successfully transfected with expression plasmids. * <span class="html-italic">p</span> ≤ 0.05.</p> Full article ">Figure 6
<p>Overexpression of SIP fragments blocks the formation of SGs induced by sorafenib. (<b>A</b>) Screen for SG-inducing anticancer compounds. HeLa cells stably expressing GFP-G3BP2 were treated with 10 μM compounds (geldanamycin, vinorelbine, and ceritinib) or 50 μM sorafenib for 2 h and captured for fluorescent images. (<b>B</b>) Immunofluorescence showing that overexpression of SIP fragments effectively inhibited sorafenib-induced SGs. HeLa cells were transfected with indicated expression plasmids, treated with 50 μM sorafenib for 2 h and subjected to immunofluorescence staining using the anti-G3BP1 antibody. Empty triangles indicate cells without SGs. Scale bars: 20 µm. (<b>C</b>) Statistical analysis of SG induction efficiency shown in panel (<b>B</b>), which is reflected by the percentage of SG-positive cells among cells successfully transfected with expression plasmids. * <span class="html-italic">p</span> ≤ 0.05.</p> Full article ">Figure 7
<p>Synthesized peptides TAT-SIP-C1/2 and SIP-U1-Antp inhibit sorafenib-induced SGs and promote the sensitivity to sorafenib in HeLa cells. (<b>A</b>) Immunofluorescence showing that TAT-SIP-C1/2 and SIP-U1-Antp significantly reduced sorafenib-induced SGs. HeLa cells were pretreated with peptides for 2 h followed by incubation with 50 μM sorafenib for an additional 2 h, and then subjected to immunofluorescence staining using the anti-G3BP1 antibody. Nuclei of HeLa cells were co-stained with DAPI. Scale bars: 20 µm. (<b>B</b>) Statistical analysis of SG induction efficiency shown in panel (<b>A</b>), which is reflected by the percentage of SG-positive cells among all cells. (<b>C</b>) Annexin V/PI flow cytometry assay showing that TAT-SIP-C1/2 and SIP-U1-Antp significantly increased sorafenib-induced cell death. HeLa cells were pretreated with peptides for 2 h followed by incubation with 50 μM sorafenib for an additional 2 h, and then subjected to Annexin V/PI flow cytometry assay. (<b>D</b>) Statistical analysis of cell death shown in panel (<b>C</b>), which is reflected by the percentage of dead cells (a combined population of Annexin V<sup>+</sup>PI<sup>+</sup>, Annexin V<sup>+</sup>PI<sup>−</sup>, and Annexin V<sup>−</sup>PI<sup>+</sup>) among all cells. * <span class="html-italic">p</span> ≤ 0.05.</p> Full article ">Figure 8
<p>Working model of SIPs that increase the efficacy of sorafenib in cancer cells. Sorafenib imposes stress on cancer cells, which respond to induce SGs that promote stress adaptation and cell survival. SIP-C1/2 and SIP-U1 derived from SG core proteins Caprin1 and USP10 exert a dominant effect and USP10-mimic effect on the SG-promoting function of G3BP1, leading to inhibition on SG assembly and cell survival. Combined treatment of SG-inducing anticancer drugs with SIPs might alleviate SG-associated drug resistance.</p> Full article ">
12 pages, 5161 KiB  
Article
Cori Ester as the Ligand for Monovalent Cations
by Krystyna Stępniak, Tadeusz Lis, Elżbieta Łastawiecka and Anna E. Kozioł
Molecules 2024, 29(9), 2133; https://doi.org/10.3390/molecules29092133 - 4 May 2024
Viewed by 1479
Abstract
Gerty T. and Carl F. Cori discovered, during research on the metabolism of sugars in organisms, the important role of the phosphate ester of a simple sugar. Glucose molecules are released from glycogen—the glucose stored in the liver—in the presence of phosphates and [...] Read more.
Gerty T. and Carl F. Cori discovered, during research on the metabolism of sugars in organisms, the important role of the phosphate ester of a simple sugar. Glucose molecules are released from glycogen—the glucose stored in the liver—in the presence of phosphates and enter the blood as α-D-glucose-1-phosphate (Glc-1PH2). Currently, the crystal structure of three phosphates, Glc-1PNa2·3.5·H2O, Glc-1PK2·2H2O, and Glc-1PHK, is known. Research has shown that reactions of Glc-1PH2 with carbonates produce new complexes with ammonium ions [Glc-1P(NH4)2·3H2O] and mixed complexes: potassium–sodium and ammonium–sodium [Glc-1P(X)1.5Na0.5·4H2O; X = K or NH4]. The crystallization of dicationic complexes has been carried out in aqueous systems containing equimolar amounts of cations (1:1; X–Na). It was found that the first fractions of crystalline complexes always had cations in the ratio 3/2:1/2. The second batch of crystals obtained from the remaining mother liquid consisted either of the previously studied Na+, K+ or NH4+ complexes, or it was a new sodium hydrate—Glc-1PNa2·5·H2O. The isolated ammonium–potassium complex shows an isomorphic cation substitution and a completely unique composition: Glc-1PH(NH4)xK1−x (x = 0.67). The Glc-1P2− ligand has chelating fragments and/or bridging atoms, and complexes containing one type of cation show different modes of coordinating oxygen atoms with cations. However, in the case of the potassium–sodium and ammonium–sodium structures, high structural similarities are observed. The 1D and 2D NMR spectra showed that the conformation of Glc-1P2− is rigid in solution as in the solid state, where only rotations of the phosphate group around the C-O-P bonds are observed. Full article
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<p>Structure of <span class="html-italic">α</span>-D-glucopyranosyl-1-phosphate ester.</p> Full article ">Figure 2
<p>The crystal packing of isomorphic complexes; view down the c axis. The Na/NH<sub>4</sub> cation positions on the 2-fold axes are marked as <span class="html-fig-inline" id="molecules-29-02133-i001"><img alt="Molecules 29 02133 i001" src="/molecules/molecules-29-02133/article_deploy/html/images/molecules-29-02133-i001.png"/></span>.</p> Full article ">Figure 3
<p>The crystal packing of α-D-glucose 1-hydrogenphosphate complexes, viewed the a axis. (<b>left</b>) Glc-1PH(NH<sub>4</sub>)<sub>0.69</sub>K<sub>0.31</sub>; (<b>right</b>) Glc-1PHK [<a href="#B18-molecules-29-02133" class="html-bibr">18</a>].</p> Full article ">Figure 4
<p>Molecular fitting of Glc-1P<sup>2−</sup> dianions; the pyranose ring is fitted. The Glc-1P2K anion is marked in navy blue, Glc-1P2Na-3.5H2O in yellow, Glc-1P2Na-5H2O in standard atom colors, Glc-1P2(NH4) in green, Glc-1P(NH4)Na in light blue, and Glc-1PKNa in burgundy. Values of the torsion angles describing orientation of the O6 hydroxyl and P1 phosphate atoms are given.</p> Full article ">Figure 5
<p>View of the Glc-1P2- dianions and surrounding cations. The hydrogen bonds are marked as blue dahsed lines. The intra-anionic distances between chelating O5 and O6 atoms are as follows: (<b>a</b>) 2.75 Å; (<b>b</b>) 2.76 Å; (<b>c</b>) 2.91 Å; (<b>d</b>) 2.77 Å; (<b>e</b>) 2.80 Å; and (<b>f</b>) 2.76 Å.</p> Full article ">Figure 6
<p>View of two Glc-1P<sup>2−</sup> dianions chelating the Na cation located on the two-fold axis.</p> Full article ">Figure 7
<p>View of the Glc-1HP<sup>−</sup> anions and surrounding cations. In the structure of the NH<sub>4</sub>/K complex (<b>a</b>), the isomorphic cation substitution (NH<sub>4</sub>:K = 69%:31%) is marked only in one position.</p> Full article ">Figure 8
<p><sup>31</sup>P NMR spectra of α-D-glucose 1-phosphate complexes (Glc-1P2K, Glc-1P2Na and Glc-1PKNa) in D<sub>2</sub>O, with no decoupling, at 202 MHz.</p> Full article ">Scheme 1
<p>Crystalline products obtained after the reaction of <span class="html-italic">α</span>-D-glucose-1-phosphate ester with monovalent cations.</p> Full article ">
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