Molecules

12 pages, 5096 KiB

Open AccessArticle

Theoretical Analysis of Superior Photodegradation of Methylene Blue by Cerium Oxide/Reduced Graphene Oxide vs. Graphene

by Nguyen Hoang Hao, Phung Thi Lan, Nguyen Ngoc Ha, Le Minh Cam and Nguyen Thi Thu Ha

Molecules 2024, 29(16), 3821; https://doi.org/10.3390/molecules29163821 (registering DOI) - 12 Aug 2024

Density functional theory and a semi-empirical quantum chemical approach were used to evaluate the photocatalytic efficiency of ceria (CeO₂) combined with reduced graphene oxide (rGO) and graphene (GP) for degrading methylene blue (MB). Two main aspects were examined: the adsorption ability [...] Read more.

Density functional theory and a semi-empirical quantum chemical approach were used to evaluate the photocatalytic efficiency of ceria (CeO₂) combined with reduced graphene oxide (rGO) and graphene (GP) for degrading methylene blue (MB). Two main aspects were examined: the adsorption ability of rGO and GP for MB, and the separation of photogenerated electrons and holes in CeO₂/rGO and CeO₂/GP. Our results, based on calculations of the adsorption energy, population analysis, bond strength index, and reduced density gradient, show favorable energetics for MB adsorption on both rGO and GP surfaces. The process is driven by weak, non-covalent interactions, with rGO showing better MB adsorption. A detailed analysis involving parameters like fractional occupation density, the centroid distance between molecular orbitals, and the Lewis acid index of the catalysts highlights the effective charge separation in CeO₂/rGO compared to CeO₂/GP. These findings are crucial for understanding photocatalytic degradation mechanisms of organic dyes and developing efficient photocatalysts. Full article

(This article belongs to the Topic Advances in Computational Materials Sciences)

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11 pages, 1690 KiB

Open AccessArticle

Evaluation of Nitric Oxide-Donating Properties of 11H-indeno[1,2-b]quinoxalin-11-one Oxime (IQ-1) by Electron Paramagnetic Resonance Spectroscopy

by Viacheslav V. Andrianov, Igor A. Schepetkin, Leah V. Bazan, Khalil L. Gainutdinov, Anastasia R. Kovrizhina, Dmitriy N. Atochin and Andrei I. Khlebnikov

Molecules 2024, 29(16), 3820; https://doi.org/10.3390/molecules29163820 (registering DOI) - 12 Aug 2024

Abstract

IQ-1 (11H-indeno[1,2-b]quinoxalin-11-one oxime) is a specific c-Jun N-terminal kinase (JNK) inhibitor with anticancer and neuro- and cardioprotective properties. Because aryloxime derivatives undergo cytochrome P450-catalyzed oxidation to nitric oxide (NO) and ketones in liver microsomes, NO formation may be an [...] Read more.

IQ-1 (11H-indeno[1,2-b]quinoxalin-11-one oxime) is a specific c-Jun N-terminal kinase (JNK) inhibitor with anticancer and neuro- and cardioprotective properties. Because aryloxime derivatives undergo cytochrome P450-catalyzed oxidation to nitric oxide (NO) and ketones in liver microsomes, NO formation may be an additional mechanism of IQ-1 pharmacological action. In the present study, electron paramagnetic resonance (EPR) of the Fe²⁺ complex with diethyldithiocarbamate (DETC) as a spin trap and hemoglobin (Hb) was used to detect NO formation from IQ-1 in the liver and blood of rats, respectively, after IQ-1 intraperitoneal administration (50 mg/kg). Introducing the spin trap and IQ-1 led to signal characteristics of the complex (DETC)₂-Fe²⁺-NO in rat liver. Similarly, the introduction of the spin trap components and IQ-1 resulted in an increase in the Hb-NO signal for both the R- and the T-conformers in blood samples. The density functional theory (DFT) calculations were in accordance with the experimental data and indicated that the NO formation of IQ-1 through the action of superoxide anion radical is thermodynamically favorable. We conclude that the administration of IQ-1 releases NO during its oxidoreductive bioconversion in vivo. Full article

(This article belongs to the Section Analytical Chemistry)

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Figure 1
Typical EPR spectra of liver samples. The rats were injected with the (DETC)2–Fe2+ spin trap components and IQ-1, as described in Materials and Methods. The temperature was 77 K. The spectral amplitudes are normalized to the sample weight. Solid black lines show sample spectra and dashed magenta lines display the contribution of the (DETC)2–Fe2+–NO signal in the sample spectrum. Full article ">Figure 2
Typical EPR spectra of the blood samples (Panel A) and extracted signals for R- and T-conformers of hemoglobin (Panel B). The rats were injected with (DETC)2–Fe2+ spin trap components and IQ-1, as described in Materials and Methods. The temperature was 77 K. The spectral amplitudes are normalized to the sample weight. Solid black lines (Panel A) show sample spectra. The dashed magenta lines and solid blue lines (Panel B) show the contribution of the R- and T-conformer signals to the sample spectrum, respectively. Full article ">Figure 3
The structures of ferrous complexes (DETC)2-Fe2+ (Panel A) and (DETC)2–Fe2+–NO (Panel B) optimized by the DFT method with PBE0 functional and def2-TZVPD basis set. Full article ">Figure 4
The DFT-optimized geometric structures (gas phase) of the anion–radical adduct A·− formed from the compounds IQ-1 (Panel A) and AL1 (Panel B) in step (1) (see <a href="#molecules-29-03820-sch002" class="html-scheme">Scheme 2</a>). The carbon, hydrogen, nitrogen, and oxygen atoms are shown as yellow, light-blue, magenta, and red balls, respectively. Full article ">Scheme 1
Proposed pathway of NO formation involving cytochrome P450. Full article ">Scheme 2
The proposed mechanism for the oxidative transformation of the C=N−OH group “outside the active site”. Full article ">

11 pages, 3054 KiB

Open AccessArticle

Enhanced TiO₂-Based Photocatalytic Volatile Organic Compound Decomposition Combined with Ultrasonic Atomization in the Co-Presence of Carbon Black and Heavy Metal Nanoparticles

by Zen Maeno, Mika Nishitani, Takehiro Saito, Kazuhiko Sekiguchi, Naoki Kagi and Norikazu Namiki

Molecules 2024, 29(16), 3819; https://doi.org/10.3390/molecules29163819 (registering DOI) - 12 Aug 2024

Abstract

Volatile organic compounds (VOCs) are representative indoor air pollutants that negatively affect the human body owing to their toxicity. One of the most promising methods for VOC removal is photocatalytic degradation using TiO₂. In this study, the addition of carbon black [...] Read more.

Volatile organic compounds (VOCs) are representative indoor air pollutants that negatively affect the human body owing to their toxicity. One of the most promising methods for VOC removal is photocatalytic degradation using TiO₂. In this study, the addition of carbon black (CB) and heavy metal nanoparticles (NPs) was investigated to improve the efficiency of a TiO₂-based photocatalytic VOC decomposition system combined with ultrasonic atomization and ultraviolet irradiation, as described previously. The addition of CB and Ag NPs significantly improved the degradation efficiency. A comparison with other heavy metal nanoparticles and their respective roles are discussed. Full article

(This article belongs to the Special Issue Materials in the Application of Adsorption, Degradation, Catalysis and Water Treatment)

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23 pages, 6456 KiB

Open AccessArticle

Slowing Down the “Magic Bullet”: Encapsulation of Imatinib in Fe-MOF for Cardiotoxicity Reduction and Improvement in Anticancer Activity

by Weronika Strzempek, Elżbieta Menaszek, Monika Papiez and Barbara Gil

Molecules 2024, 29(16), 3818; https://doi.org/10.3390/molecules29163818 (registering DOI) - 12 Aug 2024

Viewed by 61

Abstract

Imatinib, a small molecule kinase inhibitor, is used as a cancer growth blocker. However, one of its most serious side effects is congestive cardiac failure. Reducing drug toxicity may be achieved through the use of drug delivery systems. Biocompatible metal-organic framework (MOF) materials, [...] Read more.

Imatinib, a small molecule kinase inhibitor, is used as a cancer growth blocker. However, one of its most serious side effects is congestive cardiac failure. Reducing drug toxicity may be achieved through the use of drug delivery systems. Biocompatible metal-organic framework (MOF) materials, namely FeMIL-100 and FeMIL-101-NH₂, were employed as potential imatinib carriers. They efficiently delivered the drug as an anticancer agent while minimizing cardiotoxicity. Notably, the release of imatinib from FeMIL-100 was rapid in acidic conditions and slower in pH-neutral environments, allowing targeted delivery to cancer cells. The carrier’s pH-dependent stability governed the drug release mechanism. Two release models—Korsmeyer–Peppas and Weibull—were fitted to the experimental data and discussed in terms of drug release from a rigid microporous matrix. Cytotoxicity tests were conducted on two cell lines: HL60 (a model cell line for acute myeloid leukemia) and H9c2 (a cell line for cardiomyocytes). Overall, the metal-organic framework (MOF) carriers mitigated imatinib’s adverse effects without compromising its effectiveness. Full article

(This article belongs to the Topic Challenges and Opportunities in Drug Delivery Research)

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19 pages, 5059 KiB

Open AccessReview

Hydrogen Production from Ammonia Decomposition: A Mini-Review of Metal Oxide-Based Catalysts

by Senliang Xi, Wenying Wu, Wenhao Yao, Ruodan Han, Sha He, Wenju Wang, Teng Zhang and Liang Yu

Molecules 2024, 29(16), 3817; https://doi.org/10.3390/molecules29163817 (registering DOI) - 12 Aug 2024

Viewed by 86

Abstract

Efficient hydrogen storage and transportation are crucial for the sustainable development of human society. Ammonia, with a hydrogen storage density of up to 17.6 wt%, is considered an ideal energy carrier for large-scale hydrogen storage and has great potential for development and application [...] Read more.

Efficient hydrogen storage and transportation are crucial for the sustainable development of human society. Ammonia, with a hydrogen storage density of up to 17.6 wt%, is considered an ideal energy carrier for large-scale hydrogen storage and has great potential for development and application in the “hydrogen economy”. However, achieving ammonia decomposition to hydrogen under mild conditions is challenging, and therefore, the development of suitable catalysts is essential. Metal oxide-based catalysts are commonly used in the industry. This paper presents a comprehensive review of single and composite metal oxide catalysts for ammonia decomposition catalysis. The focus is on analyzing the conformational relationships and interactions between metal oxide carriers and active metal sites. The aim is to develop new and efficient metal oxide-based catalysts for large-scale green ammonia decomposition. Full article

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16 pages, 2414 KiB

Open AccessArticle

Using Extracted Sugars from Spoiled Date Fruits as a Sustainable Feedstock for Ethanol Production by New Yeast Isolates

by Georgia Antonopoulou, Maria Kamilari, Dimitra Georgopoulou and Ioanna Ntaikou

Molecules 2024, 29(16), 3816; https://doi.org/10.3390/molecules29163816 (registering DOI) - 11 Aug 2024

Viewed by 451

Abstract

This study focuses on investigating sugar recovery from spoiled date fruits (SDF) for sustainable ethanol production using newly isolated yeasts. Upon their isolation from different food products, yeast strains were identified through PCR amplification of the D1/D2 region and subsequent comparison with the [...] Read more.

This study focuses on investigating sugar recovery from spoiled date fruits (SDF) for sustainable ethanol production using newly isolated yeasts. Upon their isolation from different food products, yeast strains were identified through PCR amplification of the D1/D2 region and subsequent comparison with the GenBank database, confirming isolates KKU30, KKU32, and KKU33 as Saccharomyces cerevisiae; KKU21 as Zygosaccharomyces rouxii; and KKU35m as Meyerozyma guilliermondii. Optimization of sugar extraction from SDF pulp employed response surface methodology (RSM), varying solid loading (20–40%), temperature (20–40 °C), and extraction time (10–30 min). Linear models for sugar concentration (R1) and extraction efficiency (R2) showed relatively high R² values, indicating a good model fit. Statistical analysis revealed significant effects of temperature and extraction time on extraction efficiency. The results of batch ethanol production from SDF extracts using mono-cultures indicated varying consumption rates of sugars, biomass production, and ethanol yields among strains. Notably, S. cerevisiae strains exhibited rapid sugar consumption and high ethanol productivity, outperforming Z. rouxii and M. guilliermondii, and they were selected for scaling up the process at fed-batch mode in a co-culture. Co-cultivation resulted in complete sugar consumption and higher ethanol yields compared to mono-cultures, whereas the ethanol titer reached 46.8 ± 0.2 g/L. Full article

(This article belongs to the Special Issue Novel Biochemical Processes for Treatment and Valorization of Wastes and Biomass)

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Full article ">Figure 1
Maximum likelihood (ML) dendrogram based on the D1/D2 region of the 26S ribosomal DNA for the five samples of this study highlighted in magenta (KKU21, KKU30, KKU32, KKU33, and KKU35) and 13 yeast sequences downloaded from GenBank with their accession numbers. In blue are the samples analyzed in Ntaikou et al. [<a href="#B17-molecules-29-03816" class="html-bibr">17</a>]. Bootstrap support values over 75% are shown. Full article ">Figure 2
The normal plot of residuals for both responses (sugar concentration, R1; extraction efficiency, R2). Full article ">Figure 3
Responses R1 (sugar concentration) and R2 (extraction efficiency) for temperature and organic loading at given specific extraction time. Full article ">Figure 4
Consumption of sugars (a,d,g,j,m), microbial growth (b,e,h,k,n), and ethanol evolution (c,f,i,l,o) during alcoholic fermentation of SDF extracts (L, low concentration; H, high concentration) using the isolates KKU21, KKU30, KKU32, KKU33, and KKU35 in batch mode. Full article ">Figure 5
Changes of the pH values of the fermentation broth during alcoholic fermentation of SDF extracts (L, low concentration; H, high concentration) using the isolates KKU21 (a), KKU30 (b), KKU32 (c), KKU33 (d), and KKU35 (e), respectively, in batch mode. Full article ">Figure 6
Comparative overall sugar consumption (a) and maximum ethanol yields (YEtOH) (b) estimated during alcoholic fermentation of SDF extracts (L, low concentration; H, high concentration) using the isolates KKU21, KKU30, KKU32, KKU33, and KKU35, respectively, in batch mode. Full article ">Figure 7
Sugar consumption and ethanol production (a) as well as pH change (b) during alcoholic fermentation of SDF extract using the co-culture of strains KKU30 and KKU33 in fed-batch mode. Full article ">

13 pages, 11706 KiB

Open AccessArticle

Chemical Profile and Potential Applications of Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro Kernel Oils: Analysis of Volatile Compounds and Fatty Acids

by Callistus Bvenura and Learnmore Kambizi

Molecules 2024, 29(16), 3815; https://doi.org/10.3390/molecules29163815 (registering DOI) - 11 Aug 2024

Viewed by 327

Abstract

Sclerocarya birrea kernel volatile compounds and fatty acid methyl esters (FAMEs) from the Bubi district in Matabeleland North province of Zimbabwe were characterised by GC–MS. The volatile compounds of the oil include 65 different compounds from 24 distinct classes, dominated by 13 alcohols [...] Read more.

Sclerocarya birrea kernel volatile compounds and fatty acid methyl esters (FAMEs) from the Bubi district in Matabeleland North province of Zimbabwe were characterised by GC–MS. The volatile compounds of the oil include 65 different compounds from 24 distinct classes, dominated by 13 alcohols and 14 aldehydes (42%). Other classes include carboxylic acids, phenols, sesquiterpenes, lactones, pyridines, saturated fatty acids, ketones, and various hydrocarbons. The kernel oils revealed essential fatty acids such as polyunsaturated (α-linolenic and linoleic acids) and monounsaturated fatty acids (palmitic, palmitoleic, and oleic acids). Notably, oleic acid is the predominant fatty acid at 521.61 mg/g, constituting approximately 73% of the total fatty acids. Linoleic acid makes up 8%, and saturated fatty acids make up about 7%, including significant amounts of stearic (42.45 mg/g) and arachidic (3.46 mg/g) acids. These results validate the use of marula oils in food, pharmaceutical, and health industries, as well as in the multibillion USD cosmetics industry. Therefore, the potential applications of S. berria kernel oils are extensive, necessitating further research and exploration to fully unlock their capabilities. Full article

(This article belongs to the Special Issue Functional Evaluation of Bioactive Compounds from Natural Sources)

26 pages, 4780 KiB

Open AccessArticle

Synthesis, Structural Properties and Biological Activities of Novel Hydrazones of 2-, 3-, 4-Iodobenzoic Acid

by Izabela Czyżewska, Liliana Mazur, Anna Biernasiuk, Anna Hordyjewska and Łukasz Popiołek

Molecules 2024, 29(16), 3814; https://doi.org/10.3390/molecules29163814 (registering DOI) - 11 Aug 2024

Viewed by 389

Abstract

Nowadays, searching for novel antimicrobial agents is crucial due to the increasing number of resistant bacterial strains. Moreover, cancer therapy is a major challenge for modern medicine. Currently used cytostatics have a large number of side effects and insufficient therapeutic effects. Due to [...] Read more.

Nowadays, searching for novel antimicrobial agents is crucial due to the increasing number of resistant bacterial strains. Moreover, cancer therapy is a major challenge for modern medicine. Currently used cytostatics have a large number of side effects and insufficient therapeutic effects. Due to the above-mentioned facts, we undertook research to synthesize novel compounds from the acylhydrazone group aimed at obtaining potential antimicrobial and anticancer agents. As a starting material, we employed hydrazides of 2-, 3- or 4-iodobenzoic acid, which gave three series of acylhydrazones in the condensation reaction with various aldehydes. The chemical structure of all obtained compounds was confirmed by IR, ¹H NMR, and ¹³C NMR. The structure of selected compounds was determined by single-crystal X-ray diffraction analysis. Additionally, all samples were characterized using powder X-ray diffraction. The other issue in this research was to examine the possibility of the solvent-free synthesis of compounds using mechanochemical methods. The biological screening results revealed that some of the newly synthesized compounds indicated a beneficial antimicrobial effect even against MRSA—the methicillin-resistant Staphylococcus aureus ATCC 43300 strain. In many cases, the antibacterial activity of synthesized acylhydrazones was equal to or better than that of commercially available antibacterial agents that were used as reference substances in this research. Significantly, the tested compounds do not show toxicity to normal cell lines either. Full article

(This article belongs to the Special Issue Probing Pharmacological and Biological Performance of Synthetic and Natural Compounds—2nd Edition)

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PXRD patterns of compound 13: (a) simulated from the SCXRD data; (b) experimental after synthesis from solution; (c–e) experimental after liquid-assisted grinding (LAG) for 30, 60 and 90 min, respectively, using ethanol as a solvent; (f) experimental after LAG for 90 min using acetonitrile. Full article ">Figure 2
Perspective view of the molecules constituting the asymmetric part in crystals 13, 13∙ACN, 20 and 26a with the atom-numbering scheme. Thermal ellipsoids are drawn at the 50% probability level. Dashed lines indicate the hydrogen bonds. Full article ">Figure 3
Molecular overlay of the conformers found in: (a) polymorphic modifications 26a (red line), 26b (green line) and 26c (dark blue line); (b) unsolvated crystal 13 (molecule 13A—blue line, molecule 13B—green line) and its solvate 13∙ACN (pink line). Full article ">Figure 4
Part of the crystal structure of 13·ACN in view along the a axis, showing the formation of channels filled in by the solvent molecules. Full article ">Figure 5
Part of the crystal structure of 9 showing (a) supramolecular chains stabilized via strong N1–H1n∙∙∙O1A/N1A–H1nA∙∙∙O1 (x, y + 1, z) hydrogen bonds and weak C–H∙∙∙O/π interactions; (b) crystal packing viewed along the b axis with marked 2D layer parallel to the (−102) crystallographic plane. Molecules 9-A and 9-B are marked in green and blue, respectively. Dashed lines indicate hydrogen bonds. Full article ">Figure 6
(a) Part of the crystal structure of 26a showing hydrogen-bonding motifs; (b) crystal packing in 26a viewed along the b axis; (c) crystal packing in 26b viewed down the a axis; (d) hydrogen-bonding patterns in crystal 26c, (e) part of the crystal structure of 26c in view along the a axis. Dashed lines indicate inter- and intramolecular interactions. Full article ">Scheme 1
Synthesis of the hydrazides of 2-, 3- or 4-iodobenzoic acid. Full article ">Scheme 2
Synthesis of the acylhydrazones of 2-, 3- or 4-iodobenzoic acid. Full article ">

15 pages, 11176 KiB

Open AccessArticle

Study on Calcination Characteristics of Diaspore-Kaolin Bauxite Based on Machine Vision

by Longjiang Li and Jun Liu

Molecules 2024, 29(16), 3813; https://doi.org/10.3390/molecules29163813 (registering DOI) - 11 Aug 2024

Viewed by 241

Abstract

D-K-type bauxite from Guizhou can be used as an unburned ceramic, adsorbent, and geopolymer after low-temperature calcination. It aims to solve the problem where the color of the D–K-type bauxite changes after calcination at different temperatures. Digital image processing technology was used to [...] Read more.

D-K-type bauxite from Guizhou can be used as an unburned ceramic, adsorbent, and geopolymer after low-temperature calcination. It aims to solve the problem where the color of the D–K-type bauxite changes after calcination at different temperatures. Digital image processing technology was used to extract the color characteristics of bauxite images after 10 min of calcination at various temperatures. Then, we analyzed changes in the chemical composition and micromorphology of bauxite before and after calcination and investigated the correlation between the color characteristics of images and composition changes after bauxite calcination. The test results indicated that after calcining bauxite at 500 °C to 1000 °C for 10 min, more obvious dehydration and decarburization reactions occurred. The main component gradually changed from diaspore to Al₂O₃, the chromaticity value of the image decreased from 0.0980 to 0.0515, the saturation value increased from 0.0161 to 0.2433, and the brightness value increased from 0.5890 to 0.7177. Studies have shown that changes in bauxite color characteristics are strongly correlated with changes in composition. This is important for directing bauxite calcination based on digital image processing from engineering viewpoints. Full article

(This article belongs to the Special Issue Molecular Structure of Minerals)

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12 pages, 5229 KiB

Open AccessArticle

Study of Mesoporous Zr-TiO₂ Catalyst with Rich Oxygen Vacancies for N-Methylmorpholine Oxidation to N-Methylmorpholine-N-oxide

by Yongwei Li, Zhihao Fang, Lijuan Feng, Fangfang Liu, Yucui Shi, Jiao Li and Chao Zhao

Molecules 2024, 29(16), 3812; https://doi.org/10.3390/molecules29163812 (registering DOI) - 11 Aug 2024

Viewed by 319

Abstract

A series of Zr-TiO₂ catalysts were prepared using a facile sol-gel method and were used for N-methylmorpholine (NMM) oxidation to N-methylmorpholine-N-oxide (NMMO). The structure features of Zr-TiO₂ catalysts were studied in detail through a variety of characterization methods, such as XRD, [...] Read more.

A series of Zr-TiO₂ catalysts were prepared using a facile sol-gel method and were used for N-methylmorpholine (NMM) oxidation to N-methylmorpholine-N-oxide (NMMO). The structure features of Zr-TiO₂ catalysts were studied in detail through a variety of characterization methods, such as XRD, SEM, N₂ adsorption-desorption isotherms, XPS, EPR, and O₂-TPD. As-obtained 5%Zr-TiO₂ catalysts had superior catalytic performance and stability with a 97.6% NMMO yield at 40 °C, which related to Zr doping, a higher surface area, more oxygen vacancies, and oxygen chemisorption on the catalytic surface. This work provides an efficient preparation strategy of TiO₂-based catalysts for selective oxidation reactions by a facile method. Full article

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XRD pattern comparison of the catalysts. Full article ">Figure 2
SEM (a), TEM (b–d), and EDS mapping of Zr, Ti, and O element (e–h) of 5%Zr-TiO2. Full article ">Figure 3
(a) N2 adsorption-desorption isothermal profiles and (b) pore size distribution of the catalysts. Full article ">Figure 4
XPS spectra of all catalysts: (a) Ti 2p, (b) Zr 3d, and (c) O 1s. Full article ">Figure 5
(a) O2-TPD spectrum and (b) EPR profiles of the catalysts. Full article ">Figure 6
(a) Catalyst screening. Conditions: 0.1 mol NMM, 0.13 mol H2O2, 20 mg catalysts, 30 °C, 0.5 h. (b) Effect of temperature. Conditions: 0.1 mol NMM, 0.13 mol H2O2, 20 mg 5%Zr-TiO2, 3 h. (c) Effect of time. Conditions: 0.1 mol NMM, 0.13 mol H2O2, 20 mg 5%Zr-TiO2, 40 °C. (d) Effect of catalyst dosage. Conditions: 0.1 mol NMM, 0.13 mol H2O2, 40 °C, 3 h. (e) Effect of H2O2 dosage. Conditions: 0.1 mol NMM, 20 mg 5%Zr-TiO2, 40 °C, 3 h. (f) Cycling stability of 5%Zr-TiO2. Full article ">Scheme 1
The schematic diagram of the catalytic oxidation process. Full article ">

18 pages, 3637 KiB

Open AccessArticle

A New Wound-Healing Tool Based on Glycyrrhiza glabra Extract-Loaded Ufasomes on Spanish Broom Dressings

by Simone Rossello, Manuela Mandrone, Teresa Cerchiara, Ilaria Chiocchio, Martina Rossi, Fabio Chinnici, Valentina Sallustio, Maria Aponte, Giuseppe Blaiotta, Barbara Luppi, Angela Abruzzo, Federica Bigucci and Concettina Cappadone

Molecules 2024, 29(16), 3811; https://doi.org/10.3390/molecules29163811 (registering DOI) - 11 Aug 2024

Viewed by 309

Abstract

The development of innovative products for restoring skin integrity and promoting wound healing is still a challenge. The aim of this work was to evaluate an innovative Spanish broom wound dressing impregnated with Glycyrrhiza glabra extract-loaded ufasomes to improve wound healing. Ufasomes were [...] Read more.

The development of innovative products for restoring skin integrity and promoting wound healing is still a challenge. The aim of this work was to evaluate an innovative Spanish broom wound dressing impregnated with Glycyrrhiza glabra extract-loaded ufasomes to improve wound healing. Ufasomes were characterized in terms of size, polydispersity index, entrapment efficiency, zeta potential, and stability. In addition, in vitro release studies and biocompatibility, biosafety, and scratch tests on WS1 fibroblasts were performed. The loaded ufasomes showed a nanometric size (<250 nm), good size distribution (lower than 0.3), and appropriate encapsulation efficiency (~67%). Moreover, the lipid vesicles showed good stability during the storage period and allowed for a slow release of glycyrrhizin, the main bioactive compound of the extract. Biological studies revealed that loaded vesicles are not cytotoxic, are hemocompatible, and lead to the complete closure of the scratch after about 33 h. To conclude, the results suggest that the developed dressings can be efficiently used to promote the healing process. Full article

(This article belongs to the Special Issue Recent Advances in (Phospho)lipid-Based Drug Delivery Nanosystems)

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15 pages, 2988 KiB

Open AccessArticle

The Effect of Component Defects on the Performance of Perovskite Devices and the Low-Cost Preparation of High-Purity PbI₂

by Boyu Dong, Yuhan Xie and Yongbing Lou

Molecules 2024, 29(16), 3810; https://doi.org/10.3390/molecules29163810 (registering DOI) - 11 Aug 2024

Viewed by 213

Abstract

The efficiency and reproducibility of perovskite solar cells (PSCs) are significantly influenced by the purity of lead iodide (PbI₂) in the raw materials used. Pb(OH)I has been identified as the primary impurity generated from PbI₂ in water-based synthesis. Consequently, a [...] Read more.

The efficiency and reproducibility of perovskite solar cells (PSCs) are significantly influenced by the purity of lead iodide (PbI₂) in the raw materials used. Pb(OH)I has been identified as the primary impurity generated from PbI₂ in water-based synthesis. Consequently, a comprehensive investigation into the impact of Pb(OH)I impurities on film and device performance is essential. In this study, PbI₂, with varying stoichiometries, was synthesized to examine the effects of different Pb(OH)I levels on perovskite device performance. The characterization results revealed that even trace amounts of Pb(OH)I impede the formation of precursor prenucleation clusters. These impurities also increase the energy barrier of the α-phase and facilitate the transition of the intermediate phase to the δ-phase. These effects result in poor perovskite film morphology and sub-optimal photovoltaic device performance. To address these issues, a cost-effective method for preparing high-stoichiometry PbI₂ was developed. The formation of Pb(OH)I was effectively inhibited through several strategies: adjusting solution pH and temperature, modifying material addition order, simplifying the precipitation–recrystallization process, and introducing H₃PO₂ as an additive. These modifications enabled the one-step synthesis of high-purity PbI₂. PSCs prepared using this newly synthesized high-stoichiometry PbI₂ demonstrated photovoltaic performance comparable to those fabricated with commercial PbI₂ (purity ≥ 99.999%). Our novel method offers a cost-effective alternative for synthesizing high-stoichiometry PbI₂, thereby providing a viable option for the production of high-performance PSCs. Full article

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14 pages, 3380 KiB

Open AccessArticle

Effects of Fermentation with Kombucha Symbiotic Culture of Bacteria and Yeasts on Antioxidant Activities, Bioactive Compounds and Sensory Indicators of Rhodiola rosea and Salvia miltiorrhiza Beverages

by Jin Cheng, Dan-Dan Zhou, Ruo-Gu Xiong, Si-Xia Wu, Si-Yu Huang, Adila Saimaiti, Xiao-Yu Xu, Guo-Yi Tang, Hua-Bin Li and Sha Li

Molecules 2024, 29(16), 3809; https://doi.org/10.3390/molecules29163809 (registering DOI) - 11 Aug 2024

Viewed by 202

Abstract

Kombucha is a well-known fermented beverage traditionally made from black tea infusion. Recent studies have focused on finding alternative materials to create novel kombucha beverages with various health benefits. In this study, we prepared and evaluated two novel kombucha beverages using Rhodiola rosea [...] Read more.

Kombucha is a well-known fermented beverage traditionally made from black tea infusion. Recent studies have focused on finding alternative materials to create novel kombucha beverages with various health benefits. In this study, we prepared and evaluated two novel kombucha beverages using Rhodiola rosea and Salvia miltiorrhiza as materials. The effects of fermentation with the residue of these plants on the kombucha were also investigated. The antioxidant activities, total phenolic contents, and concentrations of the bioactive compounds of the kombucha beverages were determined by the Trolox equivalent antioxidant capacity test, ferric-reducing antioxidant power test, Folin–Ciocalteu method, and high-performance liquid chromatography, respectively. The results revealed that the kombucha beverages made with Rhodiola rosea and Salvia miltiorrhiza had strong antioxidant capacities and abundant phenolic contents. Additionally, the kombucha fermented with Rhodiola rosea residue had higher FRAP, TEAC and TPC values than that fermented without residue. On the other hand, the Salvia miltiorrhiza kombucha fermented with residue had similar FRAP and TEAC values but lower TPC values compared to that fermented without residue. The correlation analysis showed that gallic acid, salidroside, and tyrosol were responsible for the antioxidant abilities and total phenolic contents of the Rhodiola rosea kombucha, and salvianolic acid A and salvianolic acid B contributed to the antioxidant abilities of the Salvia miltiorrhiza kombucha. Furthermore, the kombucha fermented with Rhodiola rosea residue had the highest sensory scores among the kombucha beverages studied. These findings suggest that Rhodiola rosea and Salvia miltiorrhiza are suitable for making novel kombucha beverages with strong antioxidant abilities and abundant phenolic contents, which can be used in preventing and managing oxidative stress-related diseases. Full article

(This article belongs to the Special Issue The Impact of Advances in Fermentation Processes on the Chemical Composition of the Final Product)

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22 pages, 3747 KiB

Open AccessArticle

Macroporous Poly(hydromethylsiloxane) Networks as Precursors to Hybrid Ceramics (Ceramers) for Deposition of Palladium Catalysts

by Jan Mrówka, Robert Kosydar, Kamil Kornaus, Janusz Partyka and Magdalena Hasik

Molecules 2024, 29(16), 3808; https://doi.org/10.3390/molecules29163808 (registering DOI) - 11 Aug 2024

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Abstract

Poly(hydromethylsiloxane) (PHMS) was cross-linked with 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (D₄^Vi) in water-in-oil High Internal Phase Emulsions to form macroporous materials known as polyHIPEs. It was shown that in the process of pyrolysis under Ar atmosphere at 520 °C, the obtained polyHIPEs were converted [...] Read more.

Poly(hydromethylsiloxane) (PHMS) was cross-linked with 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (D₄^Vi) in water-in-oil High Internal Phase Emulsions to form macroporous materials known as polyHIPEs. It was shown that in the process of pyrolysis under Ar atmosphere at 520 °C, the obtained polyHIPEs were converted to ceramers with high yields (82.8–88.0 wt.%). Structurally, the obtained ceramers were hybrid ceramics, i.e., they consisted of Si-O framework and preserved organic moieties. Macropores present in the polyHIPE precursors remained in ceramers. Ceramers contained also micro- and mesopores which resulted from the precursor’s mass loss during pyrolysis. Total pore volume and BET specific surface area related to the existence of micro- and mesopores in ceramers depended on the PHMS: D₄^Vi ratio applied in polyHIPE synthesis. The highest total pore volume (0.143 cm³/g) and specific surface area (344 m²/g) were reached after pyrolysis of the precursor prepared with the lowest amount of D₄^Vi as compared to PHMS. The composite materials obtained after deposition of PdO nanoparticles onto ceramers followed by reduction of PdO by H₂ were active and selective catalysts for phenylacetylene hydrogenation to styrene. Full article

(This article belongs to the Special Issue Porous Materials as Catalysts and Sorbents)

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TG and DTG curves of the studied polyHIPEs. Note: for sample symbols please refer to <a href="#sec3dot2dot1-molecules-29-03808" class="html-sec">Section 3.2.1</a>. Full article ">Figure 2
FTIR spectra of the studied polyHIPEs (P1–P3 samples) and ceramers (C1–C3 samples). Note: for sample symbols please refer to <a href="#sec3dot2dot1-molecules-29-03808" class="html-sec">Section 3.2.1</a> and <a href="#sec3dot2dot2-molecules-29-03808" class="html-sec">Section 3.2.2</a>. Full article ">Figure 3
DRIFT spectra recorded in situ during heating of the P3 polyHIPE under Ar atmosphere. Full article ">Figure 4
SEM images of the materials before (P1) and after (C1) pyrolysis. Full article ">Figure 5
Void and window size distributions in the studied polyHIPEs and ceramers determined by analysis of SEM images. Note: for sample symbols please refer to <a href="#sec3dot2dot1-molecules-29-03808" class="html-sec">Section 3.2.1</a> and <a href="#sec3dot2dot2-molecules-29-03808" class="html-sec">Section 3.2.2</a>. Full article ">Figure 6
N2 adsorption/desorption isotherms of the studied ceramers. Note: for sample symbols please refer to <a href="#sec3dot2dot2-molecules-29-03808" class="html-sec">Section 3.2.2</a>. Full article ">Figure 7
XRD diffraction patterns of the C3 ceramer and the C3_Pd material. Note: for sample symbols please refer to <a href="#sec3dot2dot2-molecules-29-03808" class="html-sec">Section 3.2.2</a>. Full article ">Figure 8
TPR profiles of the prepared ceramer-PdO systems. Note: for sample symbols please refer to <a href="#sec3dot2dot2-molecules-29-03808" class="html-sec">Section 3.2.2</a>. Full article ">Figure 9
Results of phenylacetylene hydrogenation catalyzed by C1_Pd, C2_Pd and C3_Pd materials treated with H2 (A–C). Note: for sample symbols please refer to <a href="#sec3dot2dot2-molecules-29-03808" class="html-sec">Section 3.2.2</a>. Full article ">

15 pages, 2899 KiB

Open AccessArticle

Differential Chemical Components Analysis of Periplocae Cortex, Lycii Cortex, and Acanthopanacis Cortex Based on Mass Spectrometry Data and Chemometrics

by Xianrui Wang, Jiating Zhang, Fangliang He, Wenguang Jing, Minghua Li, Xiaohan Guo, Xianlong Cheng and Feng Wei

Molecules 2024, 29(16), 3807; https://doi.org/10.3390/molecules29163807 (registering DOI) - 11 Aug 2024

Viewed by 227

Abstract

Background: Periplocae Cortex (PC), Acanthopanacis Cortex (AC), and Lycii Cortex (LC), as traditional Chinese medicines, are all dried root bark, presented in a roll, light and brittle, easy to break, have a fragrant scent, etc. Due to their similar appearances, it is [...] Read more.

Background: Periplocae Cortex (PC), Acanthopanacis Cortex (AC), and Lycii Cortex (LC), as traditional Chinese medicines, are all dried root bark, presented in a roll, light and brittle, easy to break, have a fragrant scent, etc. Due to their similar appearances, it is tough to distinguish them, and they are often confused and adulterated in markets and clinical applications. To realize the identification and quality control of three herbs, in this paper, Ultra Performance Liquid Chromatography-Quadrupole Time of Flight Mass Spectrometry Expression (UHPLC-QTOF-MS^E) combined with chemometric analysis was used to explore the different chemical compositions. Methods: LC, AC, and PC were analyzed by UHPLC-QTOF-MS^E, and the quantized MS data combined with Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA) were used to explore the different chemical compositions with Variable Importance Projection (VIP) > 1.0. Further, the different chemical compositions were identified according to the chemical standard substances, related literature, and databases. Results: AC, PC, and LC can be obviously distinguished in PCA and PLS-DA analysis with the VIP of 2661 ions > 1.0. We preliminarily identified 17 differential chemical constituents in AC, PC, and LC with significant differences (p < 0.01) and VIP > 1.0; for example, Lycium B and Periploside H2 are LC and PC’s proprietary ingredients, respectively, and 2-Hydroxy-4-methoxybenzaldehyde, Periplocoside C, and 3,5-Di-O-caffeoylquinic acid are the shared components of the three herbs. Conclusions: UHPLC-QTOF-MS^E combined with chemometric analysis is conducive to exploring the differential chemical compositions of three herbs. Moreover, the proprietary ingredients, Lycium B (LC) and Periploside H2 (PC), are beneficial in strengthening the quality control of AC, PC, and LC. In addition, limits on the content of shared components can be set to enhance the quality control of LC, PC, and AC. Full article

(This article belongs to the Special Issue Chemometrics Tools in Analytical Chemistry 2.0)

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23 pages, 8069 KiB

Open AccessArticle

The Role of –OEt Substituents in Molybdenum-Assisted Pentathiepine Formation—Access to Diversely Functionalized Azines

by Roberto Tallarita, Lukas M. Jacobsen, Siva S. M. Bandaru, Benedict J. Elvers and Carola Schulzke

Molecules 2024, 29(16), 3806; https://doi.org/10.3390/molecules29163806 (registering DOI) - 11 Aug 2024

Viewed by 227

Abstract

1,2,3,4,5-pentathiepines (PTEs) are naturally occurring polysulfides of increasing scientific interest based on their identified pharmacological activities. Artificial PTEs with N-heterocyclic backbones are efficiently synthesized via mediation by a molybdenum–oxo-bistetrasulfido complex. A common feature of all precursor alkynes successfully used to date in [...] Read more.

1,2,3,4,5-pentathiepines (PTEs) are naturally occurring polysulfides of increasing scientific interest based on their identified pharmacological activities. Artificial PTEs with N-heterocyclic backbones are efficiently synthesized via mediation by a molybdenum–oxo-bistetrasulfido complex. A common feature of all precursor alkynes successfully used to date in this reaction is the presence of a –CH(OEt)₂ group since the previously postulated mechanism requires the presence of one OEt^– as the leaving group, and the second must become a transient ethoxonium moiety. This raised the question of whether there really is a need for two, maybe only one, or possibly even zero ethoxy substituents. This research problem was systematically addressed by respective variations in the precursor-alkyne derivatives and by employing one related allene species. It was found that the total absence of ethoxy substituents prevents the formation of PTEs entirely, while the presence of a single ethoxy group results in the possibility to distinctly functionalize the position on the resulting N-heterocyclic pyrrole five ring in the target compound. This position was previously exclusively occupied by an –OEt for all products of the molybdenum-mediated reaction. The allene was applied with similar success as precursor as with the related alkyne. The now-employable significant change in precursor composition gives access to a whole new PTE subfamily, allowing further modulation of (physico)-chemical properties such as solubility, and provides additional insight into the mechanism of PTE formation; it comprises a merely partial validation of the previous hypothesis. The new alkyne precursors and pentathiepines were characterized by a variety of instrumental analyses (NMR, mass spec, UV–vis) and in six cases (one alkyne precursor, one unexpected side product, and four PTEs) by single-crystal X-ray diffraction. Syntheses, isolation procedures, analytical data, and the impact of the findings on the previously proposed mechanism are described in detail herein. Full article

(This article belongs to the Special Issue Cyclization Reactions in Organic Synthesis: Recent Developments)

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22 pages, 5085 KiB

Open AccessReview

Ionic Liquid-Catalyzed CO₂ Conversion for Valuable Chemicals

by Peng Wang and Rui Wang

Molecules 2024, 29(16), 3805; https://doi.org/10.3390/molecules29163805 (registering DOI) - 11 Aug 2024

Viewed by 248

Abstract

CO₂ is not only the main gas that causes the greenhouse effect but also a resource with abundant reserves, low price, and low toxicity. It is expected to become an important “carbon source” to replace oil and natural gas in the future. [...] Read more.

CO₂ is not only the main gas that causes the greenhouse effect but also a resource with abundant reserves, low price, and low toxicity. It is expected to become an important “carbon source” to replace oil and natural gas in the future. The efficient and clean resource utilization of CO₂ has shown important scientific and economic value. Making full use of abundant CO₂ resources is in line with the development direction of green chemistry and has attracted the attention of scientists. Environmentally friendly ionic liquids show unique advantages in the capture and conversion of CO₂ due to their non-volatilization, designable structure, and good solubility, and show broad application prospects. The purpose of this paper is to discuss the research on the use of an ionic liquid as a catalyst to promote the synthesis of various value-added chemicals in CO₂, hoping to make full use of CO₂ resources while avoiding the defects of the traditional synthesis route, such as the use of highly toxic raw materials, complicated operation, or harsh reaction conditions. The purpose of this paper is to provide reference for the application and development of ionic liquids in CO₂ capture and conversion. Full article

(This article belongs to the Special Issue Advances of Ionic Liquids in Organic, Polymer and Material Chemistry: Key Trends in Green Chemistry)

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12 pages, 3039 KiB

Open AccessArticle

Therapeutic Potential of 1-(2-Chlorophenyl)-6,7-dimethoxy-3-methyl-3,4-dihydroisoquinoline

by Valeri Slavchev, Vera Gledacheva, Mina Pencheva, Miglena Milusheva, Stoyanka Nikolova and Iliyana Stefanova

Molecules 2024, 29(16), 3804; https://doi.org/10.3390/molecules29163804 (registering DOI) - 11 Aug 2024

Viewed by 259

Abstract

The synthesized compound 1-(2-chlorophenyl) 6-7-dimethoxy-3-methyl-3,4-dihydroisoquinoline (DIQ) was investigated as a biological agent. Its potential to affect muscle contractility was predicted through in silico PASS analysis. Based on the in silico analysis, its capabilities were experimentally investigated. The study aimed to investigate the effects [...] Read more.

The synthesized compound 1-(2-chlorophenyl) 6-7-dimethoxy-3-methyl-3,4-dihydroisoquinoline (DIQ) was investigated as a biological agent. Its potential to affect muscle contractility was predicted through in silico PASS analysis. Based on the in silico analysis, its capabilities were experimentally investigated. The study aimed to investigate the effects of DIQ on the ex vivo spontaneous contractile activity (CA) of smooth muscle (SM) tissue. DIQ was observed to reduce the strength of Ca²⁺-dependent contractions in SM preparations (SMP), possibly by increasing cytosolic Ca²⁺ levels through the activation of a voltage-gated L-type Ca²⁺ channel. DIQ potently affected calcium currents by modulating the function of muscarinic acetylcholine receptors (mAChRs) and 5-hydroxytryptamine (5-HT) receptors at a concentration of 50 μM. Immunohistochemical tests showed a 47% reduction in 5-HT_2A and 5-HT_2B receptor activity in SM cells and neurons in the myenteric plexus (MP), further confirming the effects of DIQ. Furthermore, a significant inhibition of neuronal activity was observed when the compound was co-administered with 5-HT to SM tissues. The conducted experiments confirm the ability of the isoquinoline analog to act as a physiologically active molecule to control muscle contractility and related physiological processes. Full article

(This article belongs to the Special Issue Design, Synthesis and Applications of Bioactive Compounds)

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15 pages, 1286 KiB

Open AccessArticle

Cultivated Winter-Type Lunaria annua L. Seed: Deciphering the Glucosinolate Profile Integrating HPLC, LC-MS and GC-MS Analyses, and Determination of Fatty Acid Composition

by Gina Rosalinda De Nicola, Sabine Montaut, Kayla Leclair, Joëlle Garrioux, Xavier Guillot and Patrick Rollin

Molecules 2024, 29(16), 3803; https://doi.org/10.3390/molecules29163803 (registering DOI) - 10 Aug 2024

Viewed by 445

Abstract

Lunaria annua L. (Brassicaceae) is an ornamental plant newly identified in Europe as a promising industrial oilseed crop for its valuable very-long-chain monounsaturated fatty acids (MUFAs), especially erucic acid (EA) and nervonic acid (NA). L. annua seeds were obtained from annual winter-type plants [...] Read more.

Lunaria annua L. (Brassicaceae) is an ornamental plant newly identified in Europe as a promising industrial oilseed crop for its valuable very-long-chain monounsaturated fatty acids (MUFAs), especially erucic acid (EA) and nervonic acid (NA). L. annua seeds were obtained from annual winter-type plants selected and cultivated in Northern France. Using a systematic multiple-method approach, we set out to determine the profile and content of glucosinolates (GSLs), which are the relevant chemical tag of Brassicaceae. Intact GSLs were analyzed through a well-established LC-MS method. Identification and quantification were performed by HPLC-PDA of desulfo-GSLs (dGLs) according to the official EU ISO method. Moreover, GSL structures were confirmed by GC-MS analysis of the related isothiocyanates (ITCs). Seven GSLs were identified, directly or indirectly, as follows: 1-methylethyl GSL, (1S)-1-methylpropyl GSL, (Rs)-5-(methylsulfinyl)pentyl GSL, (Rs)-6-(methylsulfinyl)hexyl GSL, (2S)-2-hydroxy-4-pentenyl GSL, 2-phenylethyl GSL, and 1-methoxyindol-3-ylmethyl GSL. In other respects, the FA composition of the seed oil was determined. Results revealed cultivated L. annua seed to be a source of NA-rich oil, and presscake as a valuable coproduct. This presscake is indeed rich in GSLs (4.3% w/w), precursors of promising bioactive molecules for agricultural and nutraceutical applications. Full article

(This article belongs to the Special Issue Isolation, Identification and Application of Biologically Active Natural Products—Second Edition)

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Structures of GSLs (R2 = SO3−) (1–5) and dGSLs (R2 = H) (d1–d7) identified and quantified in cultivated Lunaria annua seed and presscake by LC-MS and HPLC-PDA analysis. Quantification of GSLs was performed by HPLC-PDA analysis of the corresponding dGSLs. Legend: 1-methylethyl GSL (glucoputranjivin) (1), (1S)-1-methylpropyl GSL (glucocochlearin) (2), (Rs)-5-(methylsulfinyl)pentyl GSL (glucoalyssin) (3), (Rs)-6-(methylsulfinyl)hexyl GSL (glucohesperin) (4), (2S)-2-hydroxy-4-pentenyl GSL (gluconapoleiferin) (5), 2-phenylethyl GSL (gluconasturtiin) (6), 1-methoxyindol-3-ylmethyl GSL (neoglucobrassicin) (7), d-glucoputranjivin (d1), d-glucocochlearin (d2), d-glucoalyssin (d3), d-glucohesperin (d4), d-gluconapoleiferin (d5), 2-phenylethyl dGSL (d-gluconasturtiin) (d6), and 1-methoxyindol-3-ylmethyl dGSL (d-neoglucobrassicin) (d7). Full article ">Figure 2
HLPC chromatogram of the ethanolic seed extract of Lunaria annua L. Detection at 220 nm. Legend: 1-methylethyl GSL (glucoputranjivin) (1), (1S)-1-methylpropyl GSL (glucocochlearin) (hypothesis) (2), (Rs)-5-(methylsulfinyl)pentyl GSL (glucoalyssin) (3), (Rs)-6-(methylsulfinyl)hexyl GSL (glucohesperin) (4), (2S)-2-hydroxy-4-pentenyl GSL (gluconapoleiferin) (hypothesis) (5). Full article ">Figure 3
HLPC-PDA chromatogram of dGSLs obtained from the ethanolic seed extract of Lunaria annua L (Laboratory A). Detection at 229 nm. Legend: 1-methylethyl dGSL (d-glucoputranjivin) (d1), (1S)-1-methylpropyl dGSL (d-glucocochlearin) (d2), (Rs)-5-(methylsulfinyl)pentyl dGSL (d-glucoalyssin) (d3), (Rs)-6-(methylsulfinyl)hexyl dGSL (d-glucohesperin) (d4). Full article ">Figure 4
Structures of ITCs issued from enzymatic hydrolysis of GSLs and identified by GC-MS analysis. Legend: 1-methylethyl ITC (putranjivin) (i1), (1S)-1-methylpropyl ITC (i2), (Rs)-5-(methylsulfinyl)pentyl ITC (R-alyssin) (i3), (Rs)-6-(methylsulfinyl)hexyl ITC (R-hesperin) (i4). Full article ">Figure 5
Proposed mechanistic scheme for the thermal decomposition of (Rs)-5-(methylsulfinyl)pentyl ITC (R-alyssin) (i3, n = 5) and (Rs)-6-(methylsulfinyl)hexyl ITC (R-hesperin) (i4, n = 6) to the corresponding 4-pentenyl ITC (brassicanapin, n = 5) and 5-hexenyl ITC (n = 6) detected by GC-MS in the experiment with the injector port set at 250 °C. Full article ">

43 pages, 3341 KiB

Open AccessReview

New Insights Regarding the Use of Relevant Synthetic Compounds in Dentistry

by Stefania-Irina Dumitrel, Anamaria Matichescu, Stefania Dinu, Roxana Buzatu, Ramona Popovici, Dorin Cristian Dinu and Dana Cristina Bratu

Molecules 2024, 29(16), 3802; https://doi.org/10.3390/molecules29163802 (registering DOI) - 10 Aug 2024

Viewed by 340

Abstract

Worldwide, synthetic compounds are used for both in-office and at-home dental care. They are a valuable resource for both prophylactic and curative treatments for various dental problems, such as tooth decay, periodontal diseases, and many more. They are typically preferred due to their [...] Read more.

Worldwide, synthetic compounds are used for both in-office and at-home dental care. They are a valuable resource for both prophylactic and curative treatments for various dental problems, such as tooth decay, periodontal diseases, and many more. They are typically preferred due to their broad range of actions and ability to produce targeted, rapid, and long-lasting effects. Using a 0.12% chlorhexidine mouthwash is capable of reducing the plaque index from 47.69% to 2.37% and the bleeding index from 32.93% to 6.28% after just 2 weeks. Mouthwash with 0.1% OCT is also highly effective, as it significantly lowered the median plaque index and salivary bacterial counts in 152 patients in 5 days compared to a control group (p < 0.0001), while also reducing the gingival index (p < 0.001). When povidone-iodine was used as an irrigant during the surgical removal of mandibular third molars in 105 patients, it resulted in notably lower pain scores after 2 days compared to a control group (4.57 ± 0.60 vs. 5.71 ± 0.45). Sodium hypochlorite is excellent for root canal disinfection, as irrigating with 1% NaOCl completely eliminated the bacteria from canals in 65% patients. A 0.05% CPC mouthwash proved effective for perioperative patient care, significantly decreasing gingival bleeding (p < 0.001) and suppressing Streptococcus levels even one week post-surgery. Lastly, a 6% H2O2 paint-on varnish and 6% H2O2 tray formulations successfully bleached the teeth of 40 patients, maintaining a noticeably whiter appearance up to the 6-month follow-up, with significant color differences from the baseline (p < 0.005). Synthetic compounds have a large research base, which also provides a greater awareness of their mechanism of action and potential adverse effects. For a better understanding of how they work, several methods and assays are performed. These are protocolary techniques through which a compound’s efficacy and toxicity are established. Full article

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15 pages, 1248 KiB

Open AccessArticle

Impact of Incorporating Dried Chaga Mushroom (Inonotus obliquus) into Gluten-Free Bread on Its Antioxidant and Sensory Characteristics

by Zbigniew Kobus, Monika Krzywicka, Agata Blicharz-Kania, Alicja Bosacka, Anna Pecyna, Eva Ivanišová, Katarzyna Kozłowicz and Eva Kovačiková

Molecules 2024, 29(16), 3801; https://doi.org/10.3390/molecules29163801 (registering DOI) - 10 Aug 2024

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Abstract

Gluten-free bread is increasingly popular among individuals with celiac disease, and The incorporation of mushroom flour offers a novel method to enhance its nutritional profile, antioxidant content, and sensory properties. This study aimed to evaluate the antioxidant and sensory characteristics of gluten-free bread [...] Read more.

Gluten-free bread is increasingly popular among individuals with celiac disease, and The incorporation of mushroom flour offers a novel method to enhance its nutritional profile, antioxidant content, and sensory properties. This study aimed to evaluate the antioxidant and sensory characteristics of gluten-free bread with varying amounts of chaga mushroom flour (5%, 10%, 15%, 20%). The total contents of polyphenols and flavonoids were measured using a spectrophotometric method. Antioxidant activity was assessed through DPPH and FRAP methods, while textural properties were evaluated using the TPA test. Bread colour was analysed using the CIELab system, and sensory evaluation was performed by a panel of trained consumers. The results showed that gluten-free bread enriched with chaga flour had increased polyphenol and flavonoid content and enhanced antioxidant activity. The highest levels of polyphenols, flavonoids, DPPH, and FRAP activity were found in bread with 20% chaga. The addition of chaga mushroom significantly affected the bread’s hardness, cohesiveness, and chewiness. Specifically, 20% chaga flour had the most pronounced effect on hardness and elasticity, while 15% chaga flour had the greatest impact on chewiness and cohesiveness. The bread’s colour darkened with higher chaga concentrations. The results of sensory evaluation showed a negative correlation between consumer preferences and bread fortified with chaga mushroom flour. The overall consumer acceptability score indicates that only a small addition of mushroom flour (up to 10%) can be used to bake gluten-free bread. Full article

(This article belongs to the Special Issue Research on the Attainment and Biological Activity of Natural Products)

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14 pages, 2319 KiB

Open AccessArticle

Improved Anti-Oxidant and Anti-Bacterial Capacities of Skim Milk Fermented by Lactobacillus plantarum

by Ying Wang, Bingtian Zhao, Yun Ding, Nan Liu, Cheng Yang and Yajuan Sun

Molecules 2024, 29(16), 3800; https://doi.org/10.3390/molecules29163800 (registering DOI) - 10 Aug 2024

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Abstract

Milk, on account of its abundant protein content, is recognized as a vital source of bioactive substances. In this study, the bioactive ingredients in milk were obtained by a combination of protease hydrolysis and fermentation with Lactobacillus plantarum. The compositions of protease [...] Read more.

Milk, on account of its abundant protein content, is recognized as a vital source of bioactive substances. In this study, the bioactive ingredients in milk were obtained by a combination of protease hydrolysis and fermentation with Lactobacillus plantarum. The compositions of protease hydrolysate (PM) and fermentation supernatant (FM) were determined, and their anti-oxidant and anti-bacterial activities were evaluated. Using LC-MS/MS, the molecular weights and sequences of the peptides were characterized, among which a total of 25 bioactive peptides were identified. The DPPH radical scavenging results demonstrated that FM exhibited an enhanced anti-oxidant capacity compared to PM. The bacterial survival rate results revealed that FM had a remarkable anti-bacterial ability compared to PM. Additionally, the anti-bacterial component and potential anti-bacterial mechanisms were determined. The results of cytoplasmic membrane depolarization, cell membrane permeability, and morphological observation indicated that FM could interact with bacterial membranes to achieve its anti-bacterial effect. These findings suggested that FM, as a bioactive substance of natural origin, holds potential applications in the functional food, pharmaceutical, and cosmetic industries. Full article

(This article belongs to the Special Issue Functional and Bioactive Compounds in Foods: Chemical Complexities and Transformative Opportunities)

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(A) The molecular weight distributions and (B) Venn diagram of PM and FM. Full article ">Figure 2
The DPPH scavenging ability of PM and FM. * p < 0.05 and ** p < 0.01 indicate that the DPPH scavenging capacity of FM was significantly and extremely significantly higher than that of PM, respectively. Full article ">Figure 3
The bacterial survival rate of Staphylococcus aureus (A,B) and Escherichia coli (C,D) after 24 h of incubation with PM or FM at the final concentrations of 50, 100, and 200 mg/mL (A,C), with 100 and 200 mg/mL of FM or corresponding concentrations of organic acid (B,D). Different letters (a–e) indicate significant differences. Full article ">Figure 4
The cytoplasmic membrane potential of Staphylococcus aureus (A) and Escherichia coli (B) treated with samples. (*) indicates sample addition. Full article ">Figure 5
Live–dead fluorescence microscope images from Staphylococcus aureus (A) and Escherichia coli (B) with 200 mg/mL of PM and FM. The ratio of red fluorescence intensity (dead bacteria) to green fluorescence intensity (live bacteria) of Staphylococcus aureus (C) and Escherichia coli (D). The different superscript letters (a–c) indicate that the results possessed significant differences (p < 0.05). Full article ">Figure 6
SEM images of Staphylococcus aureus (A) and Escherichia coli (B) in the absence and presence of PM or FM. Full article ">

14 pages, 5002 KiB

Open AccessArticle

Synthesis and Antiallergic Activity of Dicoumarin Derivatives

by Yuying Zhang, Xiaoyu Wang and Dejun Zhou

Molecules 2024, 29(16), 3799; https://doi.org/10.3390/molecules29163799 (registering DOI) - 10 Aug 2024

Viewed by 158

Abstract

Allergies are one of the diseases whose incidence rates have increased in recent years due to the greenhouse effect and extreme climate change. Therefore, the development of new antiallergic drugs has attracted the interest of researchers in chemistry and pharmacy fields. Dicoumarin is [...] Read more.

Allergies are one of the diseases whose incidence rates have increased in recent years due to the greenhouse effect and extreme climate change. Therefore, the development of new antiallergic drugs has attracted the interest of researchers in chemistry and pharmacy fields. Dicoumarin is a coumarin derivative with various biological activities, but its antiallergic activity has not been evaluated. In this study, 14 different dicoumarin derivatives were synthesized by diethylamine-catalyzed condensation reactions of 4-hydroxycoumarin with 14 different aldehydes, and they were identified on the basis of their spectral data. The dicoumarin derivatives were subjected to studies on the degranulation of rat basophilic leukemia cells (RBL-2H3 cells) and mouse bone-marrow-derived mast cells (mBMMCs), and some of them showed good inhibitory effects on the degranulation of the two types of mast cells, demonstrating their good antiallergic activity. This study presents a new method of developing new antiallergic drugs. Full article

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14 pages, 3559 KiB

Open AccessFeature PaperArticle

Encoding CO₂ Adsorption in Sodium Zirconate by Neutron Diffraction

by Connor Gammie, Fabian Hesse, Blair Kennedy, Jan-Willem G. Bos and Aimaro Sanna

Molecules 2024, 29(16), 3798; https://doi.org/10.3390/molecules29163798 (registering DOI) - 10 Aug 2024

Viewed by 169

Abstract

Recent research into sodium zirconate as a high-temperature CO₂ sorbent has been extensive, but detailed knowledge of the material’s crystal structure during synthesis and carbon dioxide uptake remains limited. This study employs neutron diffraction (ND), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) [...] Read more.

Recent research into sodium zirconate as a high-temperature CO₂ sorbent has been extensive, but detailed knowledge of the material’s crystal structure during synthesis and carbon dioxide uptake remains limited. This study employs neutron diffraction (ND), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) to explore these aspects. An improved synthesis method, involving the pre-drying and ball milling of raw materials, produced pure samples with average crystal sizes of 37–48 nm in the monoclinic phase. However, using a slower heating rate (1 °C/min) decreased the purity. Despite this, the 1 °C/min rate resulted in the highest CO₂ uptake capacity (4.32 mmol CO₂/g Na₂ZrO₃) and CO₂ sorption rate (0.0017 mmol CO₂/g) after 5 min at 700 °C. This was attributed to a larger presence of microstructure defects that facilitate Na diffusion from the core to the shell of the particles. An ND analysis showed that the conversion of Na₂ZrO₃ was complete under the studied conditions and that CO₂ concentration significantly impacts the rate of CO₂ absorption. The TGA results indicated that the reaction rate during CO₂ sorption remained steady until full conversion due to the absorptive nature of the chemisorption process. During the sorbent reforming step, ND revealed the disappearance of Na₂O and ZrO₂ as the zirconate phase reformed. However, trace amounts of Na₂CO₃ and ZrO₂ remained after the cycles. Full article

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20 pages, 5453 KiB

Open AccessArticle

Influence of Synthesis Conditions on Catalytic Performance of Ni/CeO₂ in Aqueous-Phase Hydrogenolysis of Glycerol without External Hydrogen Input

by Clara Jarauta-Córdoba, Lucía García, Joaquín Ruiz, Miriam Oliva and Jesús Arauzo

Molecules 2024, 29(16), 3797; https://doi.org/10.3390/molecules29163797 (registering DOI) - 10 Aug 2024

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Abstract

The aqueous-phase hydrogenolysis of glycerol was studied in Ni/CeO₂ catalytic systems prepared by incipient wetness impregnation. The operating conditions were 34 bar, 227 ºC, 5 wt.% of glycerol, and a W/m_glycerol = 20 g catalyst min/g glycerol without a hydrogen supply. [...] Read more.

The aqueous-phase hydrogenolysis of glycerol was studied in Ni/CeO₂ catalytic systems prepared by incipient wetness impregnation. The operating conditions were 34 bar, 227 ºC, 5 wt.% of glycerol, and a W/m_glycerol = 20 g catalyst min/g glycerol without a hydrogen supply. The effect of the catalyst preparation conditions on the catalytic activity and physicochemical properties of the catalysts was assessed, particularly the calcination temperature of the support, the calcination temperature of the catalyst, and the Ni content. The physicochemical properties of the catalysts were determined by N₂ adsorption, H₂-TPR, NH₃-TPD, and XRD, among other techniques. A relevant increase in acidity was observed when increasing the nickel content up to 20 wt.%. The increase in the calcination temperatures of the supports and catalysts showed a detrimental effect on the specific surface area and acid properties of the catalysts, which were crucial to the selectivity of the reaction. These catalysts notably enhanced the yield of liquid products, achieving global glycerol conversion values ranging from 17.1 to 29.0% and carbon yield to liquids ranging from 12.6 to 24.0%. Acetol and 1,2-propanediol were the most abundant products obtained in the liquid stream. Full article

(This article belongs to the Topic Biomass for Energy, Chemicals and Materials)

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15 pages, 3785 KiB

Open AccessArticle

Molecular Docking-Based Virtual Screening of FDA-Approved Drugs Using Trypanothione Reductase Identified New Trypanocidal Agents

by Rogelio Gómez-Escobedo, Domingo Méndez-Álvarez, Citlali Vázquez, Emma Saavedra, Karina Vázquez, Verónica Alcántara-Farfán, Joaquín Cordero-Martínez, Alonzo Gonzalez-Gonzalez, Gildardo Rivera and Benjamín Nogueda-Torres

Molecules 2024, 29(16), 3796; https://doi.org/10.3390/molecules29163796 (registering DOI) - 10 Aug 2024

Viewed by 276

Abstract

American trypanosomiasis or Chagas disease, caused by Trypanosoma cruzi (T. cruzi), affects approximately 6–7 million people worldwide. However, its pharmacological treatment causes several uncomfortable side effects, causing patients’ treatment abandonment. Therefore, there is a need for new and better treatments. In [...] Read more.

American trypanosomiasis or Chagas disease, caused by Trypanosoma cruzi (T. cruzi), affects approximately 6–7 million people worldwide. However, its pharmacological treatment causes several uncomfortable side effects, causing patients’ treatment abandonment. Therefore, there is a need for new and better treatments. In this work, the molecular docking of nine hundred twenty-four FDA-approved drugs on three different sites of trypanothione reductase of T. cruzi (TcTR) was carried out to find potential trypanocidal agents. Finally, biological evaluations in vitro and in vivo were conducted with the selected FDA-approved drugs. Digoxin, alendronate, flucytosine, and dihydroergotamine showed better trypanocidal activity than the reference drugs benznidazole and nifurtimox in the in vitro evaluation against the trypomastigotes form. Further, these FDA-approved drugs were able to reduce 20–50% parasitemia in a short time in an in vivo model, although with less efficiency than benznidazole. Therefore, the results suggest a combined therapy of repurposed and canonical drugs against T. cruzi infection. Full article

(This article belongs to the Special Issue The Design, Synthesis, and Biological Activity of New Drug Candidates)

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Interaction profiles for the top 20 FDA-approved drugs docked and centered at the Z site. PS: The percentage of similarity; red boxes highlight the eight amino acid residues that are part of the observed consensus profile in docked inhibitors (full information in <a href="#app1-molecules-29-03796" class="html-app">Supplementary Materials</a>). Dashed lines separate between interaction types, and the number inside the colored squares indicates the number of interactions for that residue with the ligand. Full article ">Figure 2
Interaction profiles for the top 20 FDA-approved drugs docked and centered at the mepacrine site. PS: The percentage of similarity; red boxes highlight the five amino acid residues that are part of the observed consensus profile in docked inhibitors (full information in <a href="#app1-molecules-29-03796" class="html-app">Supplementary Materials</a>). Dashed lines separate between interaction types, and the number inside the colored squares indicates the number of interactions for that residue with the ligand. Full article ">Figure 3
Interaction profiles for the top 20 FDA-approved drugs docked centered at the catalytic site. PS: Percentage of similarity, red boxes highlight the six amino acid residues that are part of the observed consensus profile in docked inhibitors (full information in <a href="#app1-molecules-29-03796" class="html-app">Supplementary Materials</a>). Dashed lines separate between interaction types, and the number inside the colored squares indicates the number of interactions for that residue with the ligand. Full article ">Figure 4
RMSD graph for fluctuations over time for TcTR complex fluctuation: alendronate (1.25–4.31 Å), digoxin (1.15–3.72 Å), dihydroergotamine (0.98–9.06 Å), flucytosine (1.08–13.1 Å), and TcTR (0.33–2.22 Å). Full article ">Figure 5
The RMSF graph for fluctuations over time for TcTR complex fluctuation: alendronate, digoxin, dihydroergotamine, flucytosine, and apo-TcTR. Blue spiral (alpha helix), green triangle (beta sheet), in between space (loop). Full article ">Figure 6
The radius of the gyration graph for molecular dynamics over time for alendronate (orange), digoxin (blue), dihydroergotamine (green), flucytosine (violet), and apo-TcTR (red). Full article ">Figure 7
Four selected FDA-approved drugs for biological evaluation against trypomastigotes of T. cruzi in an in vitro model. Full article ">Figure 8
The percentage of parasite survival induced by three FDA drugs and benznidazole treatments in a short-term in vivo model of trypanosomiasis (NINOA strain). MD: Dihydroergotamine, D: digoxin, AS: alendronate. BZN reference drug. The control is infection without treatment. Full article ">

15 pages, 1165 KiB

Open AccessArticle

Numerical Modeling of Anisotropic Particle Diffusion through a Cylindrical Channel

by Michał Cieśla, Bartłomiej Dybiec, Monika Krasowska, Zuzanna Siwy and Anna Strzelewicz

Molecules 2024, 29(16), 3795; https://doi.org/10.3390/molecules29163795 (registering DOI) - 10 Aug 2024

Viewed by 219

Abstract

The transport of molecules and particles through single pores is the basis of biological processes, including DNA and protein sequencing. As individual objects pass through a pore, they cause a transient change in the current that can be correlated with the object size, [...] Read more.

The transport of molecules and particles through single pores is the basis of biological processes, including DNA and protein sequencing. As individual objects pass through a pore, they cause a transient change in the current that can be correlated with the object size, surface charge, and even chemical properties. The majority of experiments and modeling have been performed with spherical objects, while much less is known about the transport characteristics of aspherical particles, which would act as a model system, for example, for proteins and bacteria. The transport kinetics of aspherical objects is an especially important, yet understudied, problem in nanopore analytics. Here, using the Wiener process, we present a simplified model of the diffusion of rod-shaped particles through a cylindrical pore, and apply it to understand the translation and rotation of the particles as they pass through the pore. Specifically, we analyze the influence of the particles’ geometrical characteristics on the effective diffusion type, the first passage time distribution, and the particles’ orientation in the pore. Our model shows that thicker particles pass through the channel slower than thinner ones, while their lengths do not affect the passage time. We also demonstrate that both spherical and rod-shaped particles undergo normal diffusion, and the first passage time distribution follows an exponential asymptotics. The model provides guidance on how the shape of the particle can be modified to achieve an optimal passage time. Full article

(This article belongs to the Special Issue Feature Papers in Computational and Theoretical Chemistry)

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20 pages, 5455 KiB

Open AccessFeature PaperArticle

Selectivity Screening and Structure–Cytotoxic Activity Observations of Selected Oleanolic Acid (OA)-Type Saponins from the Amaranthaceae Family on a Wiade Panel of Human Cancer Cell Lines

by Karolina Grabowska, Agnieszka Galanty, Łukasz Pecio, Anna Stojakowska, Janusz Malarz, Paweł Żmudzki, Paweł Zagrodzki and Irma Podolak

Molecules 2024, 29(16), 3794; https://doi.org/10.3390/molecules29163794 (registering DOI) - 10 Aug 2024

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Abstract

Plants from the Amaranthaceae family are a source of oleanolic acid (OA)-type saponins with cytotoxic activity. Two known OA-type saponins, calenduloside E and chikusetsusaponin IVa, were isolated from the roots of Chenopodium strictum Roth. Their structures were confirmed using MS and NMR techniques. [...] Read more.

Plants from the Amaranthaceae family are a source of oleanolic acid (OA)-type saponins with cytotoxic activity. Two known OA-type saponins, calenduloside E and chikusetsusaponin IVa, were isolated from the roots of Chenopodium strictum Roth. Their structures were confirmed using MS and NMR techniques. This constitutes the inaugural report of the saponins in Ch. strictum. Both the isolated saponins and structurally similar compounds, momordin Ic and OA, were compared for their cytotoxicity against various cancer and normal cell lines (including skin, breast, thyroid, gastrointestinal, and prostate panels). Their effects were dose- and time-dependent, varying with the specific cell line and compound structure. A chemometric approach demonstrated the effects of the compounds on the cell lines. The study discusses the structure–activity observations. The key structural elements for potent cytotoxic activity included the free carboxyl group 28COOH in the sapogenin structure (OA) and the presence of a sugar moiety. The monodesmosides with glucuronic acid (GlcA) at the C3 position of OA were generally more cytotoxic than bidesmosides or OA alone. The addition of xylose in the sugar chain modified the activity towards the cancer cells depending on the specific cell line. OA-type saponins with GlcA (particularly calenduloside E and momordin Ic) represent a promising avenue for further investigation as potential anticancer agents. Full article

(This article belongs to the Special Issue Isolation and Structure Determination of Bioactive Natural Products (2nd Edition))

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Structures of compounds: calenduloside E (CE), chikusetsusaponin IVa (ChIVa), momordin Ic (MIc), and oleanolic acid. Full article ">Figure 2
The cytotoxic effects of analyzed compounds: caleduloside E (CE), chikusetsusaponin IVa (ChIVa), momordin Ic (Mic), and oleanolic acid (OA) on cancerous (FTC133, 8505C, and TPC-1) and normal (Nthy-ori 3) thyroid cells. Values are presented as the mean ± SD (standard deviation). Results from the MTT viability assay after 24 h incubation with tested substances. Results are presented as the mean ± SD. The values significantly different from the control (untreated group) are indicated by * for p ˂ 0.05. Full article ">Figure 3
The cytotoxic effects of analyzed compounds: caleduloside E (CE), chikusetsusaponin IVa (ChIVa), momordin Ic (Mic), and oleanolic acid on cancerous (DLD1, HCT-116, Caco2, HepG2, and Ht29) and normal (CCD841CoN) colon cells. Results from the MTT viability assay after 24 h incubation. Results are presented as the mean ± SD. The values significantly different from the control (untreated group) are indicated by * for p ˂ 0.05. Full article ">Figure 4
The score scatterplot of hPCA model (cell lines were depicted). Full article ">Figure 5
Dendrogram of similarity between different cell lines. Method of grouping: single linkage; function of the distance: Euclidean distance (subsequently identified clusters were marked with subsequent letters; further explanation in the text). Full article ">Figure 6
The most important structure–activity correlations for cytotoxic activity of analyzed saponins. Abbreviations: ↑—increased activity; ≈—similar activity; ↓—decreased activity; calenduloside E (CE); chikusetsusaponin IVa (ChIVa); momordin Ic (MIc); oleanolic acid (OA). Full article ">

14 pages, 2351 KiB

Open AccessArticle

Synthesis of Coumarin-Based Photosensitizers for Enhanced Antibacterial Type I/II Photodynamic Therapy

by Min Ma, Lili Luo, Libing Liu, Yuxuan Ding, Yixuan Dong and Bing Fang

Molecules 2024, 29(16), 3793; https://doi.org/10.3390/molecules29163793 (registering DOI) - 10 Aug 2024

Viewed by 203

Abstract

Photodynamic therapy (PDT) is an effective method for treating microbial infections by leveraging the unique photophysical properties of photosensitizing agents, but issues such as fluorescence quenching and the restricted generation of reactive oxygen species (ROS) under hypoxic conditions still remain. In this study, [...] Read more.

Photodynamic therapy (PDT) is an effective method for treating microbial infections by leveraging the unique photophysical properties of photosensitizing agents, but issues such as fluorescence quenching and the restricted generation of reactive oxygen species (ROS) under hypoxic conditions still remain. In this study, we successfully synthesized and designed a coumarin-based aggregation-induced emission luminogen (AIEgen), called ICM, that shows a remarkable capacity for type I ROS and type II ROS generation. The ¹O₂ yield of ICM is 0.839. The ROS it produces include hydroxyl radicals (HO^•) and superoxide anions (O₂^•−), with highly effective antibacterial properties specifically targeting Staphylococcus aureus (a Gram-positive bacterium). Furthermore, ICM enables broad-spectrum fluorescence imaging and exhibits excellent biocompatibility. Consequently, ICM, as a potent type I photosensitizer for eliminating pathogenic microorganisms, represents a promising tool in addressing the threat posed by these pathogens. Full article

(This article belongs to the Special Issue Multifunctional Nanomaterials for Bioapplications, 2nd Edition)

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Graphical abstract

Graphical abstract
Full article ">Figure 1
(A) Normalized UV–vis spectra of 10 μM ICM in H2O/DMSO; (B) normalized fluorescence spectra of 10 μM ICM in H2O/DMSO; (C) normalized fluorescence spectra in different solvents (excitation at 430 nm); (D) fluorescence spectra of ICM in DMSO solvent with different water fractions; (E) amplified fluorescence spectra at 654 nm; (F) line chart of relative fluorescence intensity (I/I0) at 500 nm and 654 nm, with I0 at 90% or 0% water fractions; (G) zeta potential of ICM; (H) DLS data of ICM. Full article ">Figure 2
(A) Fluorescence chart for the detection of total ROS with 50 nM ICM and DCFH under 5 mW/cm2 white light irradiation, with measurements taken every minute; (B) detection of 1O2 generation with enhancement of SOSG for 0.5 μM ICM under 5 mW/cm2 light irradiation; (C) detection of O2•− generation with the decomposition of DHR123 for 0.5 μM ICM under 5 mW/cm2 light irradiation; (D) detection of HO• with 0.5 μM ICM and HPF upon 5 mW/cm2 white light irradiation; (E) calculated frontier molecular orbitals, with the ΔES1T1 value for ICM used in the Gaussian 09 program package at the B3LPY/6-31G (d, p) level. Full article ">Figure 3
(A) S. aureus and different concentrations of ICM on agar plates under light (5 mW/cm2) and dark conditions; (B) survival rate graph of S. aureus treated with different concentrations of ICM; (C) SEM images of S. aureus incubated with various concentrations of ICM (scale bar: 1 μm); (D) zeta potential of S. aureus treated with different concentrations of ICM; (E) CLSM images of ICM interacting with different pathogenic microorganisms (scale bar: 10 μm). Full article ">Scheme 1
(A) Molecular structures of ICM. (B) Illustration of photophysical mechanisms of Type I and Type II photosensitizers and antibacterial application of ICM. Full article ">Scheme 2
The synthetic route of ICM. Full article ">

14 pages, 3333 KiB

Open AccessArticle

Discovery of Antibacterial Compounds with Potential Multi-Pharmacology against Staphylococcus Mur ligase Family Members by In Silico Structure-Based Drug Screening

by Mio Teshima, Kohei Monobe, Saya Okubo and Shunsuke Aoki

Molecules 2024, 29(16), 3792; https://doi.org/10.3390/molecules29163792 (registering DOI) - 10 Aug 2024

Viewed by 279

Abstract

Staphylococcus aureus (S. aureus) is a major bacterial infection in humans, leading to severe disease and causing death. The stagnation of antibiotic development in recent decades has made it difficult to combat drug-resistant infections. In this study, we performed an in [...] Read more.

Staphylococcus aureus (S. aureus) is a major bacterial infection in humans, leading to severe disease and causing death. The stagnation of antibiotic development in recent decades has made it difficult to combat drug-resistant infections. In this study, we performed an in silico structure-based drug screening (SBDS) targeting the S. aureus MurE (saMurE) enzyme involved in cell wall synthesis of S. aureus. saMurE is an enzyme that is essential for the survival of S. aureus but not present in humans. SBDS identified nine saMurE inhibitor candidates, Compounds 1–9, from a structural library of 154,118 compounds. Among them, Compound 2 showed strong antibacterial activity against Staphylococcus epidermidis (S. epidermidis) used as a model bacterium. Amino acid sequence homology between saMurE and S. epidermidis MurE is 87.4%, suggesting that Compound 2 has a similar inhibitory effect on S. aureus. Compound 2 showed an IC₅₀ value of 301 nM for S. epidermidis in the dose-dependent growth inhibition assay. Molecular dynamics simulation showed that Compound 2 binds stably to both S. aureus MurD and S. aureus MurF, suggesting that it is a potential multi-pharmacological pharmacological inhibitor. The structural and bioactivity information of Compound 2, as well as its potential multiple-target activity, could contribute to developing new antimicrobial agents based on MurE inhibition. Full article

(This article belongs to the Special Issue In Silico Methods Applied in Drug and Pesticide Discovery, 2nd Edition)

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Graphical abstract

Graphical abstract
Full article ">Figure 1
saMurE inhibitor screening strategy. Full article ">Figure 2
Growth inhibitory effect of Compounds 1–9 on bacteria (S. epidermidis). A total of 0.3% DMSO and 100 μM ampicillin (AMP) were used as samples for comparison. Compounds 1–9 (100 μM). The vertical axis is the mean +/− SEM of the results of four independent experiments. Dunnett’s test: ****; p < 0.0001; **; p < 0.0021; *; p < 0.0332; n.s. = not significant. Full article ">Figure 3
Determination of 50% growth inhibition concentration against bacteria (S. epidermidis). The vertical axis shows the relative bacterial growth rate. The horizontal axis shows the molar concentration of Compound 2. Full article ">Figure 4
MDS results for the saMurE–Compound 2 complex: (A) Transition of ligand RMSD value (nm). Ligand RMSD values were calculated by comparison with the post-equilibration pose. (B) Radius (nm) of gyration during MDS. (C) Number of intermolecular hydrogen bonds. Full article ">Figure 5
ProLIF analysis for the saMurE–Compound 2 interaction: (A) Interacting residues throughout the MDS timeframe. In the screening process, the piperazine group of Compound 2 is protonated. (B) A major (≥60% probability of presence) interaction residue group was observed throughout the entire period. Full article ">Figure 6
Toxicity verification of Compound 2 on mammalian-derived cells: (A) COS-7 cells; (B) HepG2 cells. Negative control was 0.3% DMSO and positive control was 50 μM triclosan (TCS). Concentration of Compound 2 was 100 μM. Dunnett’s test: ***; p < 0.0002; n.s. = not significant. Full article ">Figure 7
MDS results for saMur ligase–Compound 2 complexes: (A) ligand RMSD values (nm); (B) radius (nm) of gyration during MDS; (C) number of intermolecular hydrogen bonds. saMurC (black), saMurD (red), saMurF (green). Full article ">

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Molecules, Volume 29, Issue 16 (August-2 2024) – 107 articles

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