Molecules

745 KiB

Open AccessArticle

Determination and Pharmacokinetic Study of Gentiopicroside, Geniposide, Baicalin, and Swertiamarin in Chinese Herbal Formulae after Oral Administration in Rats by LC-MS/MS

by Chia-Ming Lu, Lie-Chwen Lin and Tung-Hu Tsai

Molecules 2014, 19(12), 21560-21578; https://doi.org/10.3390/molecules191221560 - 22 Dec 2014

Cited by 31 | Viewed by 8465

Abstract

A sensitive and efficient liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of gentiopicroside, geniposide, baicalin, and swertiamarin in rat plasma. To avoid the stress caused by restraint or anesthesia, a freely moving rat model was used to investigate [...] Read more.

A sensitive and efficient liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of gentiopicroside, geniposide, baicalin, and swertiamarin in rat plasma. To avoid the stress caused by restraint or anesthesia, a freely moving rat model was used to investigate the pharmacokinetics of herbal medicine after the administration of a traditional Chinese herbal prescription of Long-Dan-Xie-Gan-Tang (10 g/kg, p.o.). Analytes were separated by a C18 column with a gradient system of methanol–water containing 1 mM ammonium acetate with 0.1% formic acid. The linear ranges were 10–500 ng/mL for gentiopicroside, geniposide, and baicalin, and 5–250 ng/mL for swertiamarin in biological samples. The intra- and inter-day precision (relative standard deviation) ranged from 0.9% to 11.4% and 0.3% to 14.4%, respectively. The accuracy (relative error) was from −6.3% to 10.1% at all quality control levels. The analytical system provided adequate matrix effect and recovery with good precision and accuracy. The pharmacokinetic data demonstrated that the area under concentration-time curve (AUC) values of gentiopicroside, geniposide, baicalin, and swertiamarin were 1417 ± 83.8, 302 ± 25.8, 753 ± 86.2, and 2.5 ± 0.1 min µg/mL. The pharmacokinetic profiles provide constructive information for the dosage regimen of herbal medicine and also contribute to elucidate the absorption mechanism in herbal applications and pharmacological experiments. Full article

(This article belongs to the Section Natural Products Chemistry)

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Figure 1

Figure 1
Structure formula of (A) gentiopicroside; (B) geniposide; (C) baicalin; (D) swertiamarin; and (E) carvedilol (IS). Full article ">Figure 2
Representative MRM chromatograms of gentiopicroside (channel 1), geniposide (channel 2), baicalin (channel 3), swertiamarin (channel 4), and carvedilol (IS) (channel 5) in rat plasma: (A) blank plasma samples; (B) blank plasma samples spiked with gentiopicroside, geniposide, baicalin, swertiamarin, and carvedilol (IS) at 500, 50, 100, 25, and 10 ng/mL, respectively; (C) diluted plasma sample (×10) of gentiopicroside, geniposide, and baicalin at 240 min, and plasma sample of swertiamarin at 90 min, after oral administration of Long-Dan-Xie-Gan-Tang (10 g/kg, p.o.). Full article ">Figure 2 Cont.
Representative MRM chromatograms of gentiopicroside (channel 1), geniposide (channel 2), baicalin (channel 3), swertiamarin (channel 4), and carvedilol (IS) (channel 5) in rat plasma: (A) blank plasma samples; (B) blank plasma samples spiked with gentiopicroside, geniposide, baicalin, swertiamarin, and carvedilol (IS) at 500, 50, 100, 25, and 10 ng/mL, respectively; (C) diluted plasma sample (×10) of gentiopicroside, geniposide, and baicalin at 240 min, and plasma sample of swertiamarin at 90 min, after oral administration of Long-Dan-Xie-Gan-Tang (10 g/kg, p.o.). Full article ">Figure 3
Mean plasma concentration-time profile of (A) gentiopicroside; (B) geniposide; (C) baicalin; and (D) swertiamarin in rat plasma after oral administration of Long-Dan-Xie-Gan-Tang (LDXGT; 10 g/kg). The herbal contents of LDXGT are gentiopicroside 17.04 mg/g, geniposide 25.08 mg/g, baicalin 9.94 mg/g, and swertiamarin 0.22 mg/g. Data are expressed as mean ± S.E.M. (n = 6). Full article ">

3997 KiB

Open AccessArticle

Molecular Insights into the Genetic Diversity of Hemarthria compressa Germplasm Collections Native to Southwest China

by Zhi-Hui Guo, Kai-Xin Fu, Xin-Quan Zhang, Shi-Qie Bai, Yan Fan, Yan Peng, Lin-Kai Huang, Yan-Hong Yan, Wei Liu and Xiao Ma

Molecules 2014, 19(12), 21541-21559; https://doi.org/10.3390/molecules191221541 - 22 Dec 2014

Cited by 23 | Viewed by 6750

Abstract

Start codon targeted polymorphism (SCoT) analysis was employed to distinguish 37 whipgrass (Hemarthria compressa L.) clones and assess the genetic diversity and population structure among these genotypes. The informativeness of markers was also estimated using various parameters. Using 25 highly reproducible primer [...] Read more.

Start codon targeted polymorphism (SCoT) analysis was employed to distinguish 37 whipgrass (Hemarthria compressa L.) clones and assess the genetic diversity and population structure among these genotypes. The informativeness of markers was also estimated using various parameters. Using 25 highly reproducible primer sets, 368 discernible fragments were generated. Of these, 282 (77.21%) were polymorphic. The number of alleles per locus ranged from five to 21, and the genetic variation indices varied. The polymorphism information content (PIC) was 0.358, the Shannon diversity index (H) was 0.534, the marker index (MI) was 4.040, the resolving power (RP) was 6.108, and the genotype index (GI) was 0.782. Genetic similarity coefficients (GS) between the accessions ranged from 0.563 to 0.872, with a mean of 0.685. Their patterns observed in a dendrogram constructed using the unweighted pair group method with arithmetic mean analysis (UPGMA) based on GS largely confirmed the results of principal coordinate analysis (PCoA). PCoA was further confirmed by Bayesian model-based STRUCTURE analysis, which revealed no direct association between genetic relationship and geographical origins as validated by Mantel’s test (r = 0.2268, p = 0.9999). In addition, high-level genetic variation within geographical groups was significantly greater than that between groups, as determined by Shannon diversity analysis, analysis of molecular variance (AMOVA) and Bayesian analysis. Overall, SCoT analysis is a simple, effective and reliable technique for characterizing and maintaining germplasm collections of whipgrass and related species. Full article

(This article belongs to the Section Molecular Diversity)

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Graphical abstract

Graphical abstract
Full article ">Figure 1
Dendrogram of genetic relationships between whipgrass clones determined by SCoT. The numbers on the branches were verified by bootstrapping analysis to assess the robustness of the dendrogram topology from 1000 replicates. The symbols represent geographic groups in the cluster tree as ● Clones from Guizhou (GZ), ♦ Clones from Yunnan and Liangshan (YL), ▲ Clones from Chengdu Plain (CDL), and ■ Clones from Chongqing (CQ). The three different colors (orange, black and pink) represent morphological types (I, II and III) in the cluster tree separately. Full article ">Figure 2
Dimensions plot of the principal coordinate analysis of whipgrass clones. Genetic relationships are depicted among the 37 whipgrass genotypes by the first three components (PCo-1, PCo-2, and PCo-3) derived from PCoA of the SCoT data. The geographic origin of each clone is indicated by the symbols listed at the right; ▲: Chengdu Plain (CDL); ●: Guizhou (GZ); ♦: Clones from Yunnan and Liangshan (YL); and ■: Chongqing (CQ). The three different colors (orange, black and pink) represent morphological types (I, II and III) in the cluster tree separately. Full article ">Figure 3
Two different methods for determining the optimal value of K. (A) The Second-order statistics (ΔK) method developed by Evanno et al. [<a href="#B17-molecules-19-21541" class="html-bibr">17</a>]. (B) The ad hoc procedure described by Pritchard et al. [<a href="#B18-molecules-19-21541" class="html-bibr">18</a>]. Full article ">Figure 4
Estimated population structure for whipgrass clones (K = 2). Each individual is represented by a single color line. The greater proportion of a color (blue or gold), the greater the possibility that the represented individual belongs to the group indicated by that color. Cluster a is indicated by the color gold and Cluster b is indicated by the color blue. The symbols represent geographic groups in the cluster tree as ● Clones from Guizhou (GZ), ♦ Clones from Yunnan and Liangshan (YL), ▲ Clones from Chengdu Plain (CDL), and ■ Clones from Chongqing (CQ). The three different colors (orange, black and pink) represent morphological types (I, II and III) in the cluster tree separately. Full article ">Figure 5
Map showing the geographical locations of the 37 whipgrass clones in China, with spots indicating the collection sites. Full article ">

906 KiB

Open AccessArticle

Design and Optimisation of Bioactive Cyclic Peptides: Generation of a Down-Regulator of TNF Secretion

by Roger New, Gurpal S. Bansal, Malgorzata Dryjska, Michal Bogus, Patricia Green, Marc Feldmann and Fionula Brennan

Molecules 2014, 19(12), 21529-21540; https://doi.org/10.3390/molecules191221529 - 22 Dec 2014

Cited by 6 | Viewed by 5409

Abstract

Although strong binding interactions between protein receptor and ligand do not require the participation of a large number of amino acids in either site, short peptide chains are generally poor at recreating the types of protein-protein interactions which take place during cell recognition [...] Read more.

Although strong binding interactions between protein receptor and ligand do not require the participation of a large number of amino acids in either site, short peptide chains are generally poor at recreating the types of protein-protein interactions which take place during cell recognition and signalling process, probably because their flexible backbones prevent the side chains from forming sufficiently rigid and stable epitopes, which can take part in binding with the desired strength and specificity. In a recently-reported study, it was shown that a proto-epitope containing F, R and S amino acids has the ability to down-regulate TNF secretion by macrophages. This paper extends these findings, putting those amino acids into a short cyclic peptide scaffold, and determining the optimal configuration required to overcome the problems of conformational instability, and give rise to molecules which have potential as therapeutic agents in human disease, such as rheumatoid arthritis. Full article

(This article belongs to the Section Medicinal Chemistry)

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Representation of the distribution of amino acid headgroups on the surface of a micelle as described in reference [<a href="#B1-molecules-19-21529" class="html-bibr">1</a>], where the same combinations of amino acids can come together in many different configurations. One of these configurations will correspond to a structure with a desired biological activity. Full article ">Figure 2
(a) General structure of the cyclic peptides employed in this paper, in which non-covalent interactions between the “Σ” amino acids bring them closer together; (b) View of the peptide ring from the side, showing showing the disposition of the side chains above and below the ring. Full article ">Figure 3
Changes in level of secretion of TNF into the supernatant of CTB-stimulated J774A.1 cells overnight after exposure to cyclic peptides as follows: Lex 2.1 and 2.2 are cyclo(-DF-R-Σ-S-DF-R-Σ-S-) and cyclo(-DF-S-Σ-R-DF-S-Σ-R-) respectively, where Σ represents an amino acid with a residue consisting of a straight C10 hydrocarbon chain. Lex 2.3 and 2.4 are cyclo(-DF-R-Nle-S-DF-R-Nle-S-) and cyclo(-DF-S-Nle-R-DF-S-Nle-R-) respectively, where norleucine (Nle) contributes a four-carbon sidechain. Full article ">Figure 4
Changes in level of secretion of TNF into the supernatant of LPS-stimulated J774A.1 cells overnight after exposure to cyclic peptides as follows: Lex 2.5 and 2.6 are cyclo(dF-R-lC10-S-dF-R-lC10-S) and cyclo(dF-S-lC10-R-dF-S-lC10-R) respectively, Lex 2.9 and 2.10 are cyclo(dF-S-lC10-R-dF-S-dC10-R) and cyclo(dF-S-dC10-R-dF-S-dC10-R) respectively, and Lex 2.11 and 2.12 are cyclo(dF-R-lC10-S-dF-R-dC10-S) and cyclo(dF-R-dC10-S-dF-R-dC10-S), where C10 represents an amino acid with an extended C10 hydrocarbon chain. Full article ">Figure 5
Changes in level of secretion of TNF into the supernatant of LPS-stimulated J774A.1 cells overnight after exposure to Lex 2.6 formulated with beta hydroxypropyl cyclodextrin at different ratios to peptide by weight. Full article ">Figure 6
Effect of Lex2.6 at different concentrations on TNF secretion of cells in the cognate assay. (a) Lex 2.6 formulated with cyclodextrin in the presence of transcutol; (b) Lex 2.6 formulated with cyclodextrin in absence of transcutol. Full article ">Figure 7
(a) Effect of Lex 2.6 at different concentrations on IL-6 secretion of LPS-stimulated J774A.1 cells; (b) Effect of Lex2.6 at different concentrations on IL-6 secretion of cells in the cognate assay. In these experiments, Lex 2.6 was formulated with cyclodextrin in the absence of transcutol. Full article ">

1841 KiB

Open AccessReview

Bio and Nanomaterials Based on Fe₃O₄

by Jia-Kun Xu, Fang-Fang Zhang, Jing-Jing Sun, Jun Sheng, Fang Wang and Mi Sun

Molecules 2014, 19(12), 21506-21528; https://doi.org/10.3390/molecules191221506 - 22 Dec 2014

Cited by 160 | Viewed by 15538

Abstract

During the past few years, nanoparticles have been used for various applications including, but not limited to, protein immobilization, bioseparation, environmental treatment, biomedical and bioengineering usage, and food analysis. Among all types of nanoparticles, superparamagnetic iron oxide nanoparticles, especially Fe₃O₄ [...] Read more.

During the past few years, nanoparticles have been used for various applications including, but not limited to, protein immobilization, bioseparation, environmental treatment, biomedical and bioengineering usage, and food analysis. Among all types of nanoparticles, superparamagnetic iron oxide nanoparticles, especially Fe₃O₄, have attracted a great deal of attention due to their unique magnetic properties and the ability of being easily chemical modified for improved biocompatibility, dispersibility. This review covers recent advances in the fabrication of functional materials based on Fe₃O₄ nanoparticles together with their possibilities and limitations for application in different fields. Full article

(This article belongs to the Special Issue Bio and Nanomaterials Based on Fe3O4)

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Figure 1
Schematic representation for interaction of oleic acid (OA) modified Fe3O4 nanoparticles with sodium carbonate. OA is chemically bound to Fe3O4 nanoparticles by the carboxyl head group (-COOH) and the hydrophobic tail group is free, making it non-dispersible in aqueous medium. The hydrophobic tail in turn interacts with the free OA via hydrophobic interactions. The formulation is stabilized in aqueous medium by ionization of the carboxyl head group of free OA by sodium carbonate, wherein Na+ interact by ionic interactions with COO− group of free OA [<a href="#B75-molecules-19-21506" class="html-bibr">75</a>]. Full article ">Figure 2
Illustration of the separation mechanism of affinity chromatography utilizing Fe3O4 based composite as packing material. Full article ">Figure 3
Illustration of the moval and recovery of Hg(II) using thiol-functionalized mesoporous silica-coated magnetite nanoparticles [<a href="#B129-molecules-19-21506" class="html-bibr">129</a>]. Full article ">Figure 4
Illustration of Fe3O4 nanoparticles play a peroxidase-like role to detect the specific substrate in the presence of AU [<a href="#B148-molecules-19-21506" class="html-bibr">148</a>]. Full article ">Figure 5
Illustration of the process of target bacteria separation using superparamagnetic nano-immunobeads (SPM-NIBs) [<a href="#B41-molecules-19-21506" class="html-bibr">41</a>]. Full article ">

1103 KiB

Open AccessArticle

Transfer Hydrogenation in Open-Shell Nucleotides — A Theoretical Survey

by Florian Achrainer and Hendrik Zipse

Molecules 2014, 19(12), 21489-21505; https://doi.org/10.3390/molecules191221489 - 22 Dec 2014

Cited by 2 | Viewed by 6666

Abstract

The potential of a larger number of sugar models to act as dihydrogen donors in transfer hydrogenation reactions has been quantified through the calculation of hydrogenation energies of the respective oxidized products. Comparison of the calculated energies to hydrogenation energies of nucleobases shows [...] Read more.

The potential of a larger number of sugar models to act as dihydrogen donors in transfer hydrogenation reactions has been quantified through the calculation of hydrogenation energies of the respective oxidized products. Comparison of the calculated energies to hydrogenation energies of nucleobases shows that many sugar fragment radicals can reduce pyrimidine bases such as uracil in a strongly exothermic fashion. The most potent reducing agent is the C3' ribosyl radical. The energetics of intramolecular transfer hydrogenation processes has also been calculated for a number of uridinyl radicals. The largest driving force for such a process is found for the uridin-C3'-yl radical, whose rearrangement to the C2'-oxidized derivative carrying a dihydrouracil is predicted to be exothermic by 61.1 kJ/mol in the gas phase. Full article

(This article belongs to the Special Issue Free Radicals and Radical Ions)

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1661 KiB

Open AccessArticle

Design and Synthesis of Chalcone Derivatives as Inhibitors of the Ferredoxin — Ferredoxin-NADP⁺ Reductase Interaction of Plasmodium falciparum: Pursuing New Antimalarial Agents

by Hery Suwito, Jumina, Mustofa, Pratiwi Pudjiastuti, Much Zaenal Fanani, Yoko Kimata-Ariga, Ritsuko Katahira, Toru Kawakami, Toshimichi Fujiwara, Toshiharu Hase, Hasnah Mohd Sirat and Ni Nyoman Tri Puspaningsih

Molecules 2014, 19(12), 21473-21488; https://doi.org/10.3390/molecules191221473 - 19 Dec 2014

Cited by 47 | Viewed by 8883

Abstract

Some chalcones have been designed and synthesized using Claisen-Schmidt reactions as inhibitors of the ferredoxin and ferredoxin-NADP⁺ reductase interaction to pursue a new selective antimalaria agent. The synthesized compounds exhibited inhibition interactions between PfFd-PfFNR in the range of 10.94%–50%. [...] Read more.

Some chalcones have been designed and synthesized using Claisen-Schmidt reactions as inhibitors of the ferredoxin and ferredoxin-NADP⁺ reductase interaction to pursue a new selective antimalaria agent. The synthesized compounds exhibited inhibition interactions between PfFd-PfFNR in the range of 10.94%–50%. The three strongest inhibition activities were shown by (E)-1-(4-aminophenyl)-3-(4-methoxyphenyl)prop-2-en-1-one (50%), (E)-1-(4-aminophenyl)-3-(2,4-dimethoxyphenyl)prop-2-en-1-one (38.16%), and (E)-1-(4-aminophenyl)-3-(2,3-dimethoxyphenyl)prop-2-en-1-one (31.58%). From the docking experiments we established that the amino group of the methoxyamino chlacone derivatives plays an important role in the inhibition activity by electrostatic interaction through salt bridges and that it forms more stable and better affinity complexes with FNR than with Fd. Full article

(This article belongs to the Section Medicinal Chemistry)

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Figure 1
UV-Vis spectrum profile of the proteins PfFd and PfFNR. Full article ">Figure 2
Docking result of compound 3 generated by AutoDock4 and viewed by PyMol. (A) Docking pose of compound 3 into PfFd. The magenta color is the surface of amino acid residues of PfFd involved in the interaction with PfFNR, (B) Grid box used in docking experiment into maize leaf-FNR. Dark blue color is the surface of active amino acid residues in the interaction with maize leaf-Fd, (C) docking pose of compound 3 on maize-FNR and attached by maize-Fd. Yellow: maize leaf-FNR, red: maize leaf-Fd, and blue: compound 3. Full article ">Figure 3
Docking pose and 2D presentation of the molecular interaction of the synthesized chalcones on PfFd and maize leaf-FNR. (a) PfFd-compound 3, (b) PfFd-compound 4, and (c) PfFd -compound 5, (d) maize leaf-FNR-compound 3, (e) maize leaf-FNR-compound 4, (f) maize leaf-FNR-compound 5. Full article ">Figure 3 Cont.
Docking pose and 2D presentation of the molecular interaction of the synthesized chalcones on PfFd and maize leaf-FNR. (a) PfFd-compound 3, (b) PfFd-compound 4, and (c) PfFd -compound 5, (d) maize leaf-FNR-compound 3, (e) maize leaf-FNR-compound 4, (f) maize leaf-FNR-compound 5. Full article ">Figure 4
Chain reaction cycle applied in the inhibition assay. Full article ">

1720 KiB

Open AccessReview

1-[2-(2-Methoxyphenylamino)ethylamino]-3-(naphthalene-1- yloxy)propan-2-ol May Be a Promising Anticancer Drug

by Tomoyuki Nishizaki, Takeshi Kanno, Ayako Tsuchiya, Yoshiko Kaku, Tadashi Shimizu and Akito Tanaka

Molecules 2014, 19(12), 21462-21472; https://doi.org/10.3390/molecules191221462 - 19 Dec 2014

Cited by 11 | Viewed by 8340

Abstract

We have originally synthesized the naftopidil analogue 1-[2-(2-methoxyphenylamino)ethylamino]-3-(naphthalene-1-yloxy)propan-2-ol (HUHS 1015) as a new anticancer drug. HUHS1015 induces cell death in a wide variety of human cancer cell lines originated from malignant pleural mesothelioma, lung cancer, hepatoma, gastric cancer, colorectal cancer, bladder cancer, prostate [...] Read more.

We have originally synthesized the naftopidil analogue 1-[2-(2-methoxyphenylamino)ethylamino]-3-(naphthalene-1-yloxy)propan-2-ol (HUHS 1015) as a new anticancer drug. HUHS1015 induces cell death in a wide variety of human cancer cell lines originated from malignant pleural mesothelioma, lung cancer, hepatoma, gastric cancer, colorectal cancer, bladder cancer, prostate cancer, and renal cancer. HUHS1015-induced cell death includes necrosis (necroptosis) and apoptosis, and the underlying mechanism differs depending upon cancer cell types. HUHS1015 effectively suppresses tumor growth in mice inoculated with NCI-H2052, MKN45, or CW2 cells, with a potential similar to or higher than that of currently used anticancer drugs. Here we show how HUHS1015 might offer brilliant hope for cancer therapy. Full article

(This article belongs to the Collection Efficient Pharmaceutical and Chemical Approaches for Anticancer Therapy: Design, Preliminary Evaluations, and Further Developments)

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Figure 1
Chemical structures for naftopidil and newly synthesized naftopidil analogues. Full article ">Figure 2
The effect of naftopidil analogues on cell viability for malignant mesothelioma cell lines. MTT assay was carried out in NCI-H28, NCI-H2052, NCI-H2452, and MSTO-211H cells untreated and treated with naftopidil analogues at concentrations as indicated for 24 h. In the graphs, each point represents the mean (± SEM) percentage of control (MTT intensities for cells untreated with naftopidil analogues) (n = 4 independent experiments). Full article ">Figure 3
The effect of HUHS1015 on cell viability for a variety of human cancer cell lines. MTT assay was carried out in lung cancer cell lines (A); hepatoma cell lines (B); gastric cancer cell lines (C); bladder cancer cell lines (D); prostate cancer cell lines (E); and renal cancer cell lines (F), untreated and treated with HUHS1015 at concentrations as indicated for 24 h. In the graphs, each point represents the mean (±SEM) percentage of control (MTT intensities for cells untreated with HUHS1015) (n = 4 independent experiments). Full article ">Figure 4
Schematic pathways for HUHS1015-induced cell death. Cd-Apoptosis: caspase-dependent apoptosis; Ci-Apoptosis: caspase-independent apoptosis; ER: endoplasmic reticulum; MT: mitochondria; Ncl: nucleus. Full article ">

829 KiB

Open AccessArticle

Anti-Depressant-Like Effect of Kaempferitrin Isolated from Justicia spicigera Schltdl (Acanthaceae) in Two Behavior Models in Mice: Evidence for the Involvement of the Serotonergic System

by Julia Cassani, Ana María Dorantes-Barrón, Lilian Mayagoitia Novales, Guadalupe Alva Real and Rosa Estrada-Reyes

Molecules 2014, 19(12), 21442-21461; https://doi.org/10.3390/molecules191221442 - 19 Dec 2014

Cited by 49 | Viewed by 8774

Abstract

We evaluated the antidepressant-like effect of kaempferitrin (Km) isolated from the plant Justicia spicigera (Asteraceae), which is used in traditional medicine for relieving emotional disorders, such as “la tristeza” (sadness or dysthymia) and “el humor” (mood changes). The actions of Km were evaluated [...] Read more.

We evaluated the antidepressant-like effect of kaempferitrin (Km) isolated from the plant Justicia spicigera (Asteraceae), which is used in traditional medicine for relieving emotional disorders, such as “la tristeza” (sadness or dysthymia) and “el humor” (mood changes). The actions of Km were evaluated in a forced swimming test (FST) and a suspension tail test (TST) in mice. We explored the involvement of the serotonergic system and the hypothalamic-hypophysis-adrenal axis (HPA) in the antidepressant-like effect of Km. To evaluate nonspecific effects of Km on general activity, the open field test (OFT) was performed. Km at 5, 10, and 20 mg/kg induced an antidepressant-like effect. Sub-effective dose of Km (1 mg/kg) produced a synergistic effect with imipramine (6.25 mg/kg) and fluoxetine (10 mg/kg) but not with desipramine (3.12 mg/kg). Pretreatment with p-chlorophenylalanine methyl ester (PCPA), a serotonin synthesis inhibitor, N-{2-(4-(2-methoxyphenyl)-1-piperazinyl}-N-(2-pyridinyl)cyclohexecarboxamide (WAY-100635), a selective 5-HT_1A receptor antagonist, and 8OH-DPAT, a selective 5-HT_1A agonist, but not pindolol (10 mg/kg) blocked the anti- immobility effect induced by Km. Taken together, these results indicate that the antidepressant-like effect of Km is related to the serotonergic system, principally 5-HT_1A. This effect was not related to changes in locomotor activity. Full article

(This article belongs to the Collection Bioactive Compounds)

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3500 KiB

Open AccessArticle

Photocatalytic Oxidation of Diethyl Sulfide Vapor over TiO₂-Based Composite Photocatalysts

by Dmitry Selishchev and Denis Kozlov

Molecules 2014, 19(12), 21424-21441; https://doi.org/10.3390/molecules191221424 - 19 Dec 2014

Cited by 22 | Viewed by 6498

Abstract

Composite TiO₂/activated carbon (TiO₂/AC) and TiO₂/SiO₂ photocatalysts with TiO₂ contents in the 10 to 80 wt. % range were synthesized by the TiOSO₄ thermal hydrolysis method and characterized by AES, BET, X-ray diffraction and [...] Read more.

Composite TiO₂/activated carbon (TiO₂/AC) and TiO₂/SiO₂ photocatalysts with TiO₂ contents in the 10 to 80 wt. % range were synthesized by the TiOSO₄ thermal hydrolysis method and characterized by AES, BET, X-ray diffraction and FT-IR ATR methods. All TiO₂samples were in the anatase form, with a primary crystallite size of about 11 nm. The photocatalytic activities of the TiO₂/AC and TiO₂/SiO₂ samples were tested in the gas-phase photocatalytic oxidation (PCO) reaction of diethyl sulfide (DES) vapor in a static reactor by the FT-IR in situ method. Acetaldehyde, formic acid, ethylene and SO₂ were registered as the intermediate products which finally were completely oxidized to the final oxidation products – H₂O, CO₂, CO and SO₄²⁻ ions. The influence of the support on the kinetics of DES PCO and on the TiO₂/AC and TiO₂/SiO₂ samples’ stability during three long-term DES PCO cycles was investigated. The highest PCO rate was observed for TiO₂/SiO₂ photocatalysts. To evaluate the activity of photocatalysts the turnover frequency values (TOF) were calculated for three photocatalysts (TiO₂, TiO₂/AC and TiO₂/SiO₂) for the same amount of mineralized DES. It was demonstrated that the TOF value for composite TiO₂/SiO₂ photocatalysts was 3.5 times higher than for pure TiO₂. Full article

(This article belongs to the Special Issue Photocatalysis)

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1705 KiB

Open AccessArticle

Effects of Platycodin D on Proliferation, Apoptosis and PI3K/Akt Signal Pathway of Human Glioma U251 Cells

by Chong Xu, Guibo Sun, Guangxin Yuan, Rui Wang and Xiaobo Sun

Molecules 2014, 19(12), 21411-21423; https://doi.org/10.3390/molecules191221411 - 19 Dec 2014

Cited by 42 | Viewed by 7100

Abstract

Effects of platycodin D (PD) on the proliferation, apoptosis and PI3K/Akt signaling pathway of human glioma U251 cells were investigated. Glioma U251 cells were treated with PD at final concentrations of 0, 16.3, 40.8, 81.6, 163.2 μM, and inhibition rate, early and late [...] Read more.

Effects of platycodin D (PD) on the proliferation, apoptosis and PI3K/Akt signaling pathway of human glioma U251 cells were investigated. Glioma U251 cells were treated with PD at final concentrations of 0, 16.3, 40.8, 81.6, 163.2 μM, and inhibition rate, early and late apoptotic rate, apoptotic index, expression of apoptosis-related proteins and phosphorylation of the PI3K/Akt signaling pathway were evaluated. The results showed that compared with the control group, PD could increase the proliferation inhibition rate of U251 cells in a dose- and time -dependent manner; PD could also elevate the early and late apoptotic rate, apoptotic index and the level of pro-apoptotic proteins of glioma U251 cells, such as Bax and cleaved caspase-3, but lower the level of apoptosis inhibitory protein, such as Bcl-2; PD could increase the ratio of G₀/G₁ phase U251 cells, and lower the proportion of Sphase U251 cells and the ratio of G₂/M phase U251 cells; PD could reduce the ratio of p-Akt/Akt. The results indicate that PD can inhibit the proliferation, induce the apoptosis and cause the cell cycle arrest in human glioma U251 cells, which may be related to the inhibition of PD on the activation of PI3K/Akt signaling pathway. Full article

(This article belongs to the Section Medicinal Chemistry)

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Figure 1
The chemical structure of platycodin D (C57H92O28, M.W. 1225). Full article ">Figure 2
Effects of PD on cell growth inhibition of U251. U251 cells were treated with 0, 16.3, 40.8, 81.6 and 163.2 μM of PD for 24, 48, 72 and 96 h. Cell growth inhibition was measured by using MTT assay. Each value is presented as mean ± SD (n = 3). * p < 0.05 compared with 0 μM PD; ** p < 0.01 compared with 0 μM PD. Full article ">Figure 3
PD induced apoptosis in U251 cells. (A) flow cytometric analysis; (B) cell apoptosis rate. U251 cells were treated with 0, 16.3, 40.8, 81.6 and 163.2 μM of PD for 48 h. Then they were stained with FITC-conjugated Annexin V and PI for flow cytometric analysis. Each value is presented as mean ± SD (n = 3). ** p < 0.01 compared with 0 μM PD. Full article ">Figure 4
The effect of PD on cells apoptosis index in U251 cells. (A) Hoechst 33258 staining (×200); (B) cell apoptosis index. U251 cells were treated with 0, 16.3, 40.8, 81.6 and 163.2 μM of PD for 48 h. Then they were stained with Hoechst 33258. Each value is presented as mean ± SD (n = 3). ** p < 0.01 compared with 0 μM PD. Full article ">Figure 5
The effect of PD on the expressions of Bcl-2, Bax and cleaved caspase-3 in U251 cells. U251 cells were treated with 0, 16.3, 40.8, 81.6 and 163.2 μM of PD for 48 h. Then the expressions of target protein were evaluated by western blot assay. Each value is presented as mean ± SD (n = 3). * p < 0.05 compared with 0 μM PD; ** p < 0.01 compared with 0 μM PD. Full article ">Figure 6
The effect of PD on the cell cycle in U251 cells. U251 cells were treated with 0, 16.3, 40.8, 81.6 and 163.2 μM of PD for 48 h. Then they were stained with PI for flow cytometric analysis. Each value is presented as mean ± SD (n = 3). * p < 0.05 compared with 0 μM PD; ** p < 0.01 compared with 0 μM PD. Full article ">Figure 7
The effect of PD on the PI3K/Akt signaling pathway in U251 cells. U251 cells were treated with 0, 16.3, 40.8, 81.6 and 163.2 μM of PD for 48 h. Then the expressions of p-AKT and AKT were evaluated by western blot assay. Each value is presented as mean ± SD (n = 3). * p < 0.05 compared with 0 μM PD; ** p < 0.01 compared with 0 μM PD. Full article ">

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Open AccessArticle

A New Solid Phase Extraction for the Determination of Anthocyanins in Grapes

by Marta Ferreiro-González, Ceferino Carrera, Ana Ruiz-Rodríguez, Gerardo F. Barbero, Jesús Ayuso, Miguel Palma and Carmelo G. Barroso

Molecules 2014, 19(12), 21398-21410; https://doi.org/10.3390/molecules191221398 - 19 Dec 2014

Cited by 20 | Viewed by 7418

Abstract

A method for the concentration and cleaning of red grape extracts prior to the determination of anthocyanins by UPLC-DAD has been developed. This method is of special interest in the determination of phenolic maturity as it allows the analysis of the anthocyanins present [...] Read more.

A method for the concentration and cleaning of red grape extracts prior to the determination of anthocyanins by UPLC-DAD has been developed. This method is of special interest in the determination of phenolic maturity as it allows the analysis of the anthocyanins present in grapes. Several different SPE cartridges were assessed, including both C-18- and vinylbenzene-based cartridges. C-18-based cartridges presented a very low retention for the glucosylated anthocyanidins while vinylbenzene-based cartridges showed excellent retention for these compounds. The optimized method involves the initial conditioning of the cartridge using 10 mL of methanol and 10 mL of water, followed by loading of up to 100 mL of red grape extract. Ten mL of water was used in the washing step and anthocyanins were subsequently eluted using 1.5 mL of acidified methanol at pH 2. This method simplifies the determination of individual anthocyanins as, on the one hand, it cleans the sample of interference and, on the other hand, it increases the concentration to up to 25:1.5. The developed method has been validated with a range of different grapes and it has also been tested as a means of determining the different anthocyanins in grapes with different levels of maturity. Full article

(This article belongs to the Special Issue Anthocyanins)

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782 KiB

Open AccessArticle

Liquid Chromatographic Resolution of Fendiline and Its Analogues on a Chiral Stationary Phase Based on (+)-(18-Crown-6)-2,3,11,12-tetracarboxylic Acid

by Ga Ram Lee and Myung Ho Hyun

Molecules 2014, 19(12), 21386-21397; https://doi.org/10.3390/molecules191221386 - 19 Dec 2014

Cited by 9 | Viewed by 6762

Abstract

Fendiline, an effective anti-anginal drug for the treatment of coronary heart diseases, and its sixteen analogues were resolved on a CSP based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid. Fendiline was resolved quite well with the separation factor (α) of 1.25 and resolution (R_S) of [...] Read more.

Fendiline, an effective anti-anginal drug for the treatment of coronary heart diseases, and its sixteen analogues were resolved on a CSP based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid. Fendiline was resolved quite well with the separation factor (α) of 1.25 and resolution (R_S) of 1.55 when a mobile phase consisting of methanol–acetonitrile–trifluoroacetic acid–triethylamine at a ratio of 80/20/0.1/0.5 (v/v/v/v) was used. The comparison of the chromatographic behaviors for the resolution of fendiline and its analogues indicated that the 3,3-diphenylpropyl group bonded to the secondary amino group of fendiline is important in the chiral recognition and the difference in the steric bulkiness between the phenyl group and the methyl group at the chiral center of fendiline is also important in the chiral recognition. Full article

(This article belongs to the Special Issue Dynamic Stereochemistry)

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774 KiB

Open AccessArticle

New and Cytotoxic Components from Antrodia camphorata

by Tzong-Huei Lee, Chien-Chih Chen, Jih-Jung Chen, Hui-Fen Liao, Hsun-Shuo Chang, Ping-Jyun Sung, Mei-Hwei Tseng, Sheng-Yang Wang, Horng-Huey Ko and Yueh-Hsiung Kuo

Molecules 2014, 19(12), 21378-21385; https://doi.org/10.3390/molecules191221378 - 19 Dec 2014

Cited by 15 | Viewed by 6863

Abstract

The solid-state cultured products of Antrodia camphorata as health foods has been blooming for the past few decades in Taiwan. In continuing our studies on the chemical constituents of the solid-state cultured products of this fungus, 6-methoxy-4-methyl-2,3-(methylenedioxy)phenol (1) and 4,4'-(ethane-1,2-diyl)bis(2,3,6-trimethoxyphenol)(2 [...] Read more.

The solid-state cultured products of Antrodia camphorata as health foods has been blooming for the past few decades in Taiwan. In continuing our studies on the chemical constituents of the solid-state cultured products of this fungus, 6-methoxy-4-methyl-2,3-(methylenedioxy)phenol (1) and 4,4'-(ethane-1,2-diyl)bis(2,3,6-trimethoxyphenol)(2) together with 2,3,6-trimethoxy-4-methylphenol (3), 1(10→6)abeo-ergosta-5,7,9,22-tetraen-3α-ol (4), citreoanthrasteroid B (5) and dankasterones A (6) and B (7) were purified by a series of column chromatography. Their structures were elucidated by spectral data analysis. For bioactivity assay, compounds 4–7 showed significant cytotoxicity toward murine colorectal CT26 and human leukemia K562 cancer cell lines with IC₅₀ values ranging from 6.7 to 15.3 µM and from 12.5 to 23.1 µM, respectively. Full article

(This article belongs to the Section Natural Products Chemistry)

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826 KiB

Open AccessArticle

One New and Nine Known Flavonoids from Choerospondias axillaries and Their in Vitro Antitumor, Anti-Hypoxia and Antibacterial Activities

by Chang-Wei Li and Cheng-Bin Cui

Molecules 2014, 19(12), 21363-21377; https://doi.org/10.3390/molecules191221363 - 19 Dec 2014

Cited by 17 | Viewed by 6372

Abstract

In the present study, a new flavanoid 1, together with nine known ones 2–10 were isolated from the stem bark of Choerospondias axillaries, the fruit of which was used mainly for treatment of cardiovascular diseases in China. The structure [...] Read more.

In the present study, a new flavanoid 1, together with nine known ones 2–10 were isolated from the stem bark of Choerospondias axillaries, the fruit of which was used mainly for treatment of cardiovascular diseases in China. The structure of 1 was established on the basis of its extensive spectral data, and the absolute structures of 1 and 10 were determined by their CD data. The absolute structure of 10 was established for the first time. Among the obtained compounds, 5–8 inhibited the proliferation of K562 cells with inhibition rates of 26.6%, 65.7%, 40.4% and 45.6% at 100 µg/mL; 1 and 4–10 showed significant protective effects on anoxia-induced injury in cultured ECV304 or PC12 cells at 50 µg/mL; 8 and 9 showed antibacterial effects on Staphylococcus aureus ATCC6538 at the tested concentration of 150 µg/8 mm paper disc. Compounds 2 and 4–10 were isolated for the first time from this genus. The proliferation inhibiting activities of 7 and 8, the anti-hypoxia activities of 1 and 4–10, and the antibacterial effect of 8 and 9 on Staphylococcus aureus ATCC6538 are reported here for the first time. Full article

(This article belongs to the Section Natural Products Chemistry)

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748 KiB

Open AccessArticle

Is Development of High-Grade Gliomas Sulfur-Dependent?

by Maria Wróbel, Jerzy Czubak, Patrycja Bronowicka-Adamska, Halina Jurkowska, Dariusz Adamek and Bolesław Papla

Molecules 2014, 19(12), 21350-21362; https://doi.org/10.3390/molecules191221350 - 19 Dec 2014

Cited by 41 | Viewed by 7773

Abstract

We characterized γ-cystathionase, rhodanese and 3-mercaptopyruvate sulfurtransferase activities in various regions of human brain (the cortex, thalamus, hypothalamus, hippocampus, cerebellum and subcortical nuclei) and human gliomas with II to IV grade of malignancy (according to the WHO classification). The human brain regions, as [...] Read more.

We characterized γ-cystathionase, rhodanese and 3-mercaptopyruvate sulfurtransferase activities in various regions of human brain (the cortex, thalamus, hypothalamus, hippocampus, cerebellum and subcortical nuclei) and human gliomas with II to IV grade of malignancy (according to the WHO classification). The human brain regions, as compared to human liver, showed low γ-cystathionase activity. The activity of rhodanese was also much lower and it did not vary significantly between the investigated brain regions. The activity of 3-mercaptopyruvate sulfurtransferase was the highest in the thalamus, hypothalamus and subcortical nuclei and essentially the same level of sulfane sulfur was found in all the investigated brain regions. The investigations demonstrated that the level of sulfane sulfur in gliomas with the highest grades was high in comparison to various human brain regions, and was correlated with a decreased activity of γ-cystathionase, 3-mercaptopyruvate sulfurtransferase and rhodanese. This can suggest sulfane sulfur accumulation and points to its importance for malignant cell proliferation and tumor growth. In gliomas with the highest grades of malignancy, despite decreased levels of total free cysteine and total free glutathione, a high ratio of GSH/GSSG was maintained, which is important for the process of malignant cells proliferation. A high level of sulfane sulfur and high GSH/GSSG ratio could result in the elevated hydrogen sulfide levels. Because of the disappearance of γ-cystathionase activity in high-grade gliomas, it seems to be possible that 3-mercaptopyruvate sulfurtransferase could participate in hydrogen sulfide production. The results confirm sulfur dependence of malignant brain tumors. Full article

(This article belongs to the Special Issue Sulfur Atom: Element for Adaptation to an Oxidative Environment)

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5382 KiB

Open AccessArticle

Lignin Hydrolysis and Phosphorylation Mechanism during Phosphoric Acid–Acetone Pretreatment: A DFT Study

by Wu Qin, Lingnan Wu, Zongming Zheng, Changqing Dong and Yongping Yang

Molecules 2014, 19(12), 21335-21349; https://doi.org/10.3390/molecules191221335 - 18 Dec 2014

Cited by 22 | Viewed by 9530

Abstract

The study focused on the structural sensitivity of lignin during the phosphoric acid–acetone pretreatment process and the resulting hydrolysis and phosphorylation reaction mechanisms using density functional theory calculations. The chemical stabilities of the seven most common linkages (β-O-4, β-β, 4-O- [...] Read more.

The study focused on the structural sensitivity of lignin during the phosphoric acid–acetone pretreatment process and the resulting hydrolysis and phosphorylation reaction mechanisms using density functional theory calculations. The chemical stabilities of the seven most common linkages (β-O-4, β-β, 4-O-5, β-1, 5-5, α-O-4, and β-5) of lignin in H₃PO₄, CH₃COCH₃, and H₂O solutions were detected, which shows that α-O-4 linkage and β-O-4 linkage tend to break during the phosphoric acid–acetone pretreatment process. Then α-O-4 phosphorylation and β-O-4 phosphorylation follow a two-step reaction mechanism in the acid treatment step, respectively. However, since phosphorylation of α-O-4 is more energetically accessible than phosphorylation of β-O-4 in phosphoric acid, the phosphorylation of α-O-4 could be controllably realized under certain operational conditions, which could tune the electron and hole transfer on the right side of β-O-4 in the H₂PO₄⁻ functionalized lignin. The results provide a fundamental understanding for process-controlled modification of lignin and the potential novel applications in lignin-based imprinted polymers, sensors, and molecular devices. Full article

(This article belongs to the Section Medicinal Chemistry)

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741 KiB

Open AccessArticle

Synthesis, Characterisation and Reactions of Phosphine-Substituted Alkynylboronates and Alkynyltrifluoroborate Salts

by Jérôme F. Vivat, Sylvestre P. J. T. Bachollet, Harry Adams and Joseph P. A. Harrity

Molecules 2014, 19(12), 21324-21334; https://doi.org/10.3390/molecules191221324 - 18 Dec 2014

Viewed by 5863

Abstract

The synthesis and structural characterisation of phosphine-substituted alkynylboronates is reported. A P(III)-centred alkynylboronate (2) was prepared that showed little evidence for the conjugation of the P-lone pair to the boron via the alkyne π-system, as judged by X-ray crystallography studies of [...] Read more.

The synthesis and structural characterisation of phosphine-substituted alkynylboronates is reported. A P(III)-centred alkynylboronate (2) was prepared that showed little evidence for the conjugation of the P-lone pair to the boron via the alkyne π-system, as judged by X-ray crystallography studies of 2 and a related P(V) compound, 3. In addition, corresponding alkynyltrifluoroborate salts were prepared that showed improved stability by comparison to their boronic ester counterparts. These salts undergo Pd-catalysed cross-coupling reactions with aryl halides. Full article

(This article belongs to the Special Issue Recent Advances in Boron Chemistry)

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1816 KiB

Open AccessArticle

Effects of High Hydrostatic Pressure on Escherichia coli Ultrastructure, Membrane Integrity and Molecular Composition as Assessed by FTIR Spectroscopy and Microscopic Imaging Techniques

by María Prieto-Calvo, Miguel Prieto, Mercedes López and Avelino Alvarez-Ordóñez

Molecules 2014, 19(12), 21310-21323; https://doi.org/10.3390/molecules191221310 - 18 Dec 2014

Cited by 22 | Viewed by 8009

Abstract

High hydrostatic pressure (HHP) is a novel food processing technology that is considered as an attractive alternative to conventional heat treatments for the preservation of foods, due to its lethal effects on pathogenic and spoilage microorganisms, while causing minor effects on food quality [...] Read more.

High hydrostatic pressure (HHP) is a novel food processing technology that is considered as an attractive alternative to conventional heat treatments for the preservation of foods, due to its lethal effects on pathogenic and spoilage microorganisms, while causing minor effects on food quality and sensorial attributes. This study is aimed at investigating how HHP treatments at varying intensities in the range 50–900 MPa affect the viability, membrane integrity, ultrastructure and molecular composition of Escherichia coli. Results of membrane integrity tests (measurement of cellular leakage and monitoring of propidium iodide uptake through fluorescence microscopy) and ultrastructural observations by transmission electron microscopy demonstrated that HHP gave rise to cellular enlargement, membrane damage or detachment, DNA and protein denaturation and loss of intracellular contents. Fourier-transform infrared (FTIR) spectroscopy analyses evidenced minor changes in molecular composition in response to high pressures, which were mostly observed on the spectral region w₄ (1200–900 cm⁻¹), mainly informative of carbohydrates and polysaccharides of the cell wall. These findings suggest that exposure of E. coli cells to HHP causes alterations in their physical integrity while producing minor modifications in biochemical cellular composition. The current study increases the knowledge on the mechanisms of E. coli inactivation by HHP and provides valuable information for the design of more effective food preservation regimes based on the integration of mild HHP in combination with other food preservation strategies into a multi-target hurdle technology approach. Full article

(This article belongs to the Special Issue Advances of Vibrational Spectroscopic Technologies in Life Sciences)

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Figure 1
(A) Inactivation of Escherichia coli E218/02 (black bars) and Escherichia coli C-600 (white bars) by high hydrostatic pressure (HHP) (log CFU/mL); (B) OD260 of cell-free filtrates of Escherichia coli E218/02 (black bars) and Escherichia coli C-600 (white bars) untreated or treated with HHP at 300 MPa and 600 MPa; (C) OD280 of cell-free filtrates of Escherichia coli E218/02 (black bars) and Escherichia coli C-600 (white bars) untreated or treated with HHP at 300 MPa and 600 MPa. Results are shown as the average ± standard deviation. Full article ">Figure 1 Cont.
(A) Inactivation of Escherichia coli E218/02 (black bars) and Escherichia coli C-600 (white bars) by high hydrostatic pressure (HHP) (log CFU/mL); (B) OD260 of cell-free filtrates of Escherichia coli E218/02 (black bars) and Escherichia coli C-600 (white bars) untreated or treated with HHP at 300 MPa and 600 MPa; (C) OD280 of cell-free filtrates of Escherichia coli E218/02 (black bars) and Escherichia coli C-600 (white bars) untreated or treated with HHP at 300 MPa and 600 MPa. Results are shown as the average ± standard deviation. Full article ">Figure 2
Uptake of propidium iodide by cells of Escherichia coli E218/02 (A) and Escherichia coli C-600 (B) untreated or treated with HHP at 300 MPa and 600 MPa followed by fluorescence microscopy. Full article ">Figure 3
Representative electron micrograph sections of cells of Escherichia coli E218/02 (A) and Escherichia coli C-600 (B) untreated or treated with HHP at 300 MPa and 600 MPa. a: cytoplasmic membrane; b: cell wall; c: enlarged cell; d: disorganization of the genome area; e: condensation of cytoplasmic material in amorphous regions; f: membrane with winding shape; g: detached membrane. Full article ">Figure 3 Cont.
Representative electron micrograph sections of cells of Escherichia coli E218/02 (A) and Escherichia coli C-600 (B) untreated or treated with HHP at 300 MPa and 600 MPa. a: cytoplasmic membrane; b: cell wall; c: enlarged cell; d: disorganization of the genome area; e: condensation of cytoplasmic material in amorphous regions; f: membrane with winding shape; g: detached membrane. Full article ">Figure 4
(A) Dendrogram obtained from w4 (1200 to 900 cm−1) spectral region data of two replicates (rep 1; rep 2) of strains Escherichia coli E218/02 (Strain number 2, Str 2) and Escherichia coli C-600 (Strain number 9, Str 9) untreated or HHP-treated cells, with cluster analysis performed with the Pearson product moment correlation coefficient and by the Ward algorithm method [<a href="#B25-molecules-19-21310" class="html-bibr">25</a>]; (B) untransformed FTIR spectra (w3, w4 and w5 spectral ranges,) of E. coli E218/02 (Str 2) before and after HHP treatment at different pressures (50, 300 and 900 MPa). Full article ">Figure 4 Cont.
(A) Dendrogram obtained from w4 (1200 to 900 cm−1) spectral region data of two replicates (rep 1; rep 2) of strains Escherichia coli E218/02 (Strain number 2, Str 2) and Escherichia coli C-600 (Strain number 9, Str 9) untreated or HHP-treated cells, with cluster analysis performed with the Pearson product moment correlation coefficient and by the Ward algorithm method [<a href="#B25-molecules-19-21310" class="html-bibr">25</a>]; (B) untransformed FTIR spectra (w3, w4 and w5 spectral ranges,) of E. coli E218/02 (Str 2) before and after HHP treatment at different pressures (50, 300 and 900 MPa). Full article ">

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Open AccessReview

Applications of Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry (SPME-GC/MS) in the Study of Grape and Wine Volatile Compounds

by Annarita Panighel and Riccardo Flamini

Molecules 2014, 19(12), 21291-21309; https://doi.org/10.3390/molecules191221291 - 18 Dec 2014

Cited by 67 | Viewed by 15577

Abstract

Volatile compounds are responsible for the wine “bouquet”, which is perceived by sniffing the headspace of a glass, and of the aroma component (palate-aroma) of the overall flavor, which is perceived on drinking. Grape aroma compounds are transferred to the wine and undergo [...] Read more.

Volatile compounds are responsible for the wine “bouquet”, which is perceived by sniffing the headspace of a glass, and of the aroma component (palate-aroma) of the overall flavor, which is perceived on drinking. Grape aroma compounds are transferred to the wine and undergo minimal alteration during fermentation (e.g., monoterpenes and methoxypyrazines); others are precursors of aroma compounds which form in winemaking and during wine aging (e.g., glycosidically-bound volatile compounds and C₁₃-norisoprenoids). Headspace solid phase microextraction (HS-SPME) is a fast and simple technique which was developed for analysis of volatile compounds. This review describes some SPME methods coupled with gas chromatography/mass spectrometry (GC/MS) used to study the grape and wine volatiles. Full article

(This article belongs to the Special Issue Aromas and Volatiles of Fruits)

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1073 KiB

Open AccessArticle

Insecticidal Activities of Bark, Leaf and Seed Extracts of Zanthoxylum heitzii against the African Malaria Vector Anopheles gambiae

by Hans J. Overgaard, Patcharawan Sirisopa, Bertin Mikolo, Karl E. Malterud, Helle Wangensteen, Yuan-Feng Zou, Berit S. Paulsen, Daniel Massamba, Stephane Duchon, Vincent Corbel and Fabrice Chandre

Molecules 2014, 19(12), 21276-21290; https://doi.org/10.3390/molecules191221276 - 17 Dec 2014

Cited by 18 | Viewed by 13036

Abstract

The olon tree, Zanthoxylum heitzii (syn. Fagara heitzii) is commonly found in the central-west African forests. In the Republic of Congo (Congo-Brazzaville) its bark is anecdotally reported to provide human protection against fleas. Here we assess the insecticidal activities of Z. heitzii [...] Read more.

The olon tree, Zanthoxylum heitzii (syn. Fagara heitzii) is commonly found in the central-west African forests. In the Republic of Congo (Congo-Brazzaville) its bark is anecdotally reported to provide human protection against fleas. Here we assess the insecticidal activities of Z. heitzii stem bark, seed and leaf extracts against Anopheles gambiae s.s, the main malaria vector in Africa. Extracts were obtained by Accelerated Solvent Extraction (ASE) using solvents of different polarity and by classical Soxhlet extraction using hexane as solvent. The insecticidal effects of the crude extracts were evaluated using topical applications of insecticides on mosquitoes of a susceptible reference strain (Kisumu [Kis]), a strain homozygous for the L1014F kdr mutation (kdrKis), and a strain homozygous for the G119S Ace1R allele (AcerKis). The insecticidal activities were measured using LD₅₀ and LD₉₅ and active extracts were characterized by NMR spectroscopy and HPLC chromatography. Results show that the ASE hexane stem bark extract was the most effective compound against An. gambiae (LD₅₀ = 102 ng/mg female), but was not as effective as common synthetic insecticides. Overall, there was no significant difference between the responses of the three mosquito strains to Z. heitzii extracts, indicating no cross resistance with conventional pesticides. Full article

(This article belongs to the Collection Natural Products as Leads or Drugs against Neglected Tropical Diseases)

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928 KiB

Open AccessArticle

Largely Reduced Grid Densities in a Vibrational Self-Consistent Field Treatment Do Not Significantly Impact the ResultingWavenumbers

by Oliver M. D. Lutz, Bernd M. Rode, Günther K. Bonn and Christian W. Huck

Molecules 2014, 19(12), 21253-21275; https://doi.org/10.3390/molecules191221253 - 17 Dec 2014

Cited by 12 | Viewed by 6603

Abstract

Especially for larger molecules relevant to life sciences, vibrational self-consistent field (VSCF) calculations can become unmanageably demanding even when only first and second order potential coupling terms are considered. This paper investigates to what extent the grid density of the VSCF’s underlying potential [...] Read more.

Especially for larger molecules relevant to life sciences, vibrational self-consistent field (VSCF) calculations can become unmanageably demanding even when only first and second order potential coupling terms are considered. This paper investigates to what extent the grid density of the VSCF’s underlying potential energy surface can be reduced without sacrificing accuracy of the resulting wavenumbers. Including single-mode and pair contributions, a reduction to eight points per mode did not introduce a significant deviation but improved the computational efficiency by a factor of four. A mean unsigned deviation of 1.3% from the experiment could be maintained for the fifteen molecules under investigation and the approach was found to be applicable to rigid, semi-rigid and soft vibrational problems likewise. Deprotonated phosphoserine, stabilized by two intramolecular hydrogen bonds, was investigated as an exemplary application. Full article

(This article belongs to the Special Issue Advances of Vibrational Spectroscopic Technologies in Life Sciences)

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3589 KiB

Open AccessArticle

A Sensitive A₃B Porphyrin Nanomaterial for CO₂ Detection

by Eugenia Fagadar-Cosma, Dana Vlascici, Gheorghe Fagadar-Cosma, Anca Palade, Anca Lascu, Ionela Creanga, Mihaela Birdeanu, Rodica Cristescu and Ileana Cernica

Molecules 2014, 19(12), 21239-21252; https://doi.org/10.3390/molecules191221239 - 17 Dec 2014

Cited by 20 | Viewed by 8654

Abstract

The present report deals with the tailoring, preparation and characterization of novel nanomaterials sensitive to CO₂ for use in detection of this gas during space habitation missions. A new nanostructured material based on mixed substituted asymmetrical A₃B porphyrin: 5-(4-pyridyl)-10,15,20-tris(3,4-dimethoxyphenyl)-porphyrin (PyTDMeOPP) [...] Read more.

The present report deals with the tailoring, preparation and characterization of novel nanomaterials sensitive to CO₂ for use in detection of this gas during space habitation missions. A new nanostructured material based on mixed substituted asymmetrical A₃B porphyrin: 5-(4-pyridyl)-10,15,20-tris(3,4-dimethoxyphenyl)-porphyrin (PyTDMeOPP) was synthesized and characterized by ¹H-NMR, FT-IR, UV-vis, fluorescence, MS, HPLC and AFM. Introducing one pyridyl substituent in the 5-meso-position of porphyrin macrocycle confers some degree of hydrophilicity, which may cause self-assembly properties and a better response to increased acidity. The influence of pH and nature of the solvent upon H and J aggregates of the porphyrin are discussed. Porphyrin aggregation at the air–THF interface gave a triangular type morphology, randomly distributed but uniformly oriented. When deposition was made by multiple drop-casting operations, a network of triangles of uniform size was created and a porous structure was obtained, being reorganized finally in rings. When the deposition was made from CHCl₃, ring structures ranging in internal diameter from 300 nm to 1 µm, but with the same width of the corona circular of approx. 200 nm were obtained. This porphyrin-based material, capable of generating ring aggregates in both THF and CHCl₃, has been proven to be sensitive to CO₂ detection. The dependence between the intensity of porphyrin UV-vis absorption and the concentration of CO₂ has a good correlation of 98.4%. Full article

(This article belongs to the Section Molecular Diversity)

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704 KiB

Open AccessArticle

Antioxidant Activity of Leaf Extracts from Different Hibiscus sabdariffa Accessions and Simultaneous Determination Five Major Antioxidant Compounds by LC-Q-TOF-MS

by Jin Wang, Xianshuang Cao, Hao Jiang, Yadong Qi, Kit L. Chin and Yongde Yue

Molecules 2014, 19(12), 21226-21238; https://doi.org/10.3390/molecules191221226 - 17 Dec 2014

Cited by 48 | Viewed by 9028

Abstract

Hibiscus sabdariffa has gained attention for its antioxidant activity. There are many accessions of H. sabdariffa in the world. However, information on the quantification of antioxidant compounds in different accessions is rather limited. In this paper, a liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) method [...] Read more.

Hibiscus sabdariffa has gained attention for its antioxidant activity. There are many accessions of H. sabdariffa in the world. However, information on the quantification of antioxidant compounds in different accessions is rather limited. In this paper, a liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) method for simultaneous determination of five antioxidant compounds (neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin, and isoquercitrin) in H. sabdariffa leaves was developed. The method was validated for linearity, sensitivity, precision, repeatability and accuracy. The validated method has been successfully applied for determination of the five analytes in eight accessions of H. sabdariffa. The eight accessions of H. sabdariffa were evaluated for their antioxidant activities by DPPH free radical scavenging assay. The investigated accessions of H. sabdariffa were rich in rutin and exhibited strong antioxidant activity. The two accessions showing the highest antioxidant activities were from Cuba (No. 2) and Taiwan (No. 5). The results indicated that H. sabdariffa leaves could be considered as a potential antioxidant source for the food industry. The developed LC-Q-TOF-MS method is helpful for quality control of H. sabdariffa. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

Chemical Constituents from Licania cruegeriana and Their Cardiovascular and Antiplatelet Effects

by Omar Estrada, Whendy Contreras, Giovana Acha, Eva Lucena, Whitney Venturini, Alfonso Cardozo and Claudia Alvarado-Castillo

Molecules 2014, 19(12), 21215-21225; https://doi.org/10.3390/molecules191221215 - 17 Dec 2014

Cited by 12 | Viewed by 6520

Abstract

Three new lupane-type triterpenoids: 6β,30-dihydroxybetulinic acid glucopyranosyl ester (4), 6β,30-dihydroxybetulinic acid (5) and 6β-hydroxybetulinic acid (6), were isolated from Licania cruegeriana Urb. along with six known compounds. Their structures were elucidated on the basis of spectroscopic methods, [...] Read more.

Three new lupane-type triterpenoids: 6β,30-dihydroxybetulinic acid glucopyranosyl ester (4), 6β,30-dihydroxybetulinic acid (5) and 6β-hydroxybetulinic acid (6), were isolated from Licania cruegeriana Urb. along with six known compounds. Their structures were elucidated on the basis of spectroscopic methods, including IR, ESIMS, 1D- and 2D-NMR experiments, as well as by comparison of their spectral data with those of related compounds. All compounds were evaluated in vivo for their effects on the mean arterial blood pressure (MABP) and heart rate (HR) of spontaneously hypertensive rats (SHR) and also in vitro for their capacity to inhibit the human platelet aggregation. None of the isolated flavonoids 1–3 showed cardiovascular effects on SHR and among the isolated triterpenoids 4–9 only 5 and 6 produced a significant reduction in MABP (60.1% and 17.2%, respectively) and an elevation in HR (11.0% and 41.2%, respectively). Compounds 3, 4, 5 and 6 were able to inhibit human platelet aggregation induced by ADP, collagen and arachidonic acid with different selectivity profiles. Full article

(This article belongs to the Collection Bioactive Compounds)

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Open AccessCommunication

Design and Synthesis of a Series of Truncated Neplanocin Fleximers

by Sarah C. Zimmermann, Elizaveta O'Neill, Godwin U. Ebiloma, Lynsey J. M. Wallace, Harry P. De Koning and Katherine L. Seley-Radtke

Molecules 2014, 19(12), 21200-21214; https://doi.org/10.3390/molecules191221200 - 16 Dec 2014

Cited by 12 | Viewed by 7184

Abstract

In an effort to study the effects of flexibility on enzyme recognition and activity, we have developed several different series of flexible nucleoside analogues in which the purine base is split into its respective imidazole and pyrimidine components. The focus of this particular [...] Read more.

In an effort to study the effects of flexibility on enzyme recognition and activity, we have developed several different series of flexible nucleoside analogues in which the purine base is split into its respective imidazole and pyrimidine components. The focus of this particular study was to synthesize the truncated neplanocin A fleximers to investigate their potential anti-protozoan activities by inhibition of S-adenosylhomocysteine hydrolase (SAHase). The three fleximers tested displayed poor anti-trypanocidal activities, with EC₅₀ values around 200 μM. Further studies of the corresponding ribose fleximers, most closely related to the natural nucleoside substrates, revealed low affinity for the known T. brucei nucleoside transporters P1 and P2, which may be the reason for the lack of trypanocidal activity observed. Full article

(This article belongs to the Special Issue Nucleoside Modifications)

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Open AccessReview

Hydrogen Sulfide and Endothelium-Dependent Vasorelaxation

by Jerzy Bełtowski and Anna Jamroz-Wiśniewska

Molecules 2014, 19(12), 21183-21199; https://doi.org/10.3390/molecules191221183 - 16 Dec 2014

Cited by 77 | Viewed by 9530

Abstract

In addition to nitric oxide and carbon monoxide, hydrogen sulfide (H₂S), synthesized enzymatically from l-cysteine or l-homocysteine, is the third gasotransmitter in mammals. Endogenous H₂S is involved in the regulation of many physiological processes, including vascular tone. Although initially [...] Read more.

In addition to nitric oxide and carbon monoxide, hydrogen sulfide (H₂S), synthesized enzymatically from l-cysteine or l-homocysteine, is the third gasotransmitter in mammals. Endogenous H₂S is involved in the regulation of many physiological processes, including vascular tone. Although initially it was suggested that in the vascular wall H₂S is synthesized only by smooth muscle cells and relaxes them by activating ATP-sensitive potassium channels, more recent studies indicate that H₂S is synthesized in endothelial cells as well. Endothelial H₂S production is stimulated by many factors, including acetylcholine, shear stress, adipose tissue hormone leptin, estrogens and plant flavonoids. In some vascular preparations H₂S plays a role of endothelium-derived hyperpolarizing factor by activating small and intermediate-conductance calcium-activated potassium channels. Endothelial H₂S signaling is up-regulated in some pathologies, such as obesity and cerebral ischemia-reperfusion. In addition, H₂S activates endothelial NO synthase and inhibits cGMP degradation by phosphodiesterase 5 thus potentiating the effect of NO-cGMP pathway. Moreover, H₂S-derived polysulfides directly activate protein kinase G. Finally, H₂S interacts with NO to form nitroxyl (HNO)—a potent vasorelaxant. H₂S appears to play an important and multidimensional role in endothelium-dependent vasorelaxation. Full article

(This article belongs to the Special Issue Sulfur Atom: Element for Adaptation to an Oxidative Environment)

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Open AccessArticle

Toxicity of Evodiae fructus on Rat Liver Mitochondria: The Role of Oxidative Stress and Mitochondrial Permeability Transition

by Qingyan Cai, Jingjing Wei, Wei Zhao, Si Shi, Yu Zhang, Renrong Wei, Yue Zhang, Weirong Li and Qi Wang

Molecules 2014, 19(12), 21168-21182; https://doi.org/10.3390/molecules191221168 - 16 Dec 2014

Cited by 56 | Viewed by 8281

Abstract

Evodiae fructus (EF) has been used in China for thousands of years as an analgesic, antiemetic, anti-inflammatory and antidiarrheal drug. EF is a toxic drug and causes hepatotoxicity in humans. Although recent chronic toxicity studies performed on aqueous extract of EF has revealed [...] Read more.

Evodiae fructus (EF) has been used in China for thousands of years as an analgesic, antiemetic, anti-inflammatory and antidiarrheal drug. EF is a toxic drug and causes hepatotoxicity in humans. Although recent chronic toxicity studies performed on aqueous extract of EF has revealed that it can produce obvious cumulative hepatotoxicity, the mechanism behind this toxicity is still uncertain. In the present study, we investigated the influence of EF on oxidative stress, mitochondrial permeability transition, adenosine triphosphate (ATP), and cytochrome C release of hepatic mitochondria. Rats were divided into four groups and fed distilled water, 6, 12, 24 g/kg of aqueous extract of EF daily for 15 days. Evodiamine, rutaecarpine and evodine were quantified in the aqueous extract by high performance liquid chromatography with ultraviolet detection (HPLC/UV). The results showed that aqueous extract of EF could significantly (p < 0.05) decrease MnSOD levels to 56.50%, 46.77% and 19.67% of control group, GSH level was decreased to 74.24%, 53.97% and 47.91% of control group and MDA level was increased to 131.55%, 134.34% and 150.81% of control group in the 6, 12 and 24 g/kg groups, respectively; extract also induced mitochondria swelling, vacuolation, MPT pore opening and a significant decrease (p < 0.05) in mitochondrial potential, while ATP levels were significant decreased (p < 0.05) to 65.24%, 38.08% and 34.59% of control group in the 6, 12 and 24 g/kg groups, respectively, resulting in ATP depletion and CytC release, finally trigger cell death signaling, which are the partial hepatotoxicity mechanisms of EF. Full article

(This article belongs to the Special Issue Alkaloids: Novel Therapeutic Perspectives)

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Figure 1
Representative high performance liquid chromatography profile of standard (A) and aqueous extract of EF (B). Evodine (1), evodiamine (2) and rutaecarpine (3). Full article ">Figure 2
Effects of aqueous extract of EF on mitochondrial MnSOD (A), GSH (B) and MDA (C). Data were presented as mean ± SEM (n = 10). Compared with control group * p < 0.05. Full article ">Figure 3
Effects of aqueous extract of EF on mitochondrial permeability transition. Figure showed the decrease in absorbance at 540 nm at different time points of the mitochondria which induced by 20 µmol/L CaCl2. Data were presented as mean ± SEM (n = 10). Compared with control group * p < 0.05. Full article ">Figure 4
Mitochondrial changes in the rat liver treated with control rat (A), aqueous extract of EF 6 g/kg/day (B), 12 g/kg/day (C) and 24 g/kg/day (D) last 15 days. M mitochondria, N nucleus, the arrows showed vacuolation. Magnification 15,000×. Full article ">Figure 5
Effects of aqueous extract of EF on mitochondrial transmembrane potential by fluorescence microscope. The picture A–D are red fluorescence of groups of control, 6, 12, 24 g/kg aqueous extract of EF treated rat, successively; the E–H are green fluorescence correspond to the red. Full article ">Figure 6
Effects of aqueous extract of EF on mitochondrial transmembrane potential by fluorescence spectrophotometer. The changes of fluorescence intensity of different groups were showed. Data were presented as mean ± SEM (n = 10). Compared with control group * p < 0.05. Full article ">Figure 7
Effects of aqueous extract of EF on liver tissue ATP. Data were presented as mean ± SEM (n = 10). Compared with control group * p < 0.05. Full article ">Figure 8
Effects of aqueous extract of EF on CytC release. The concentrations of CytC in endochylema of different groups were showed. Data were presented as mean ± SEM (n = 10). Compared with control group * p < 0.05. Full article ">

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Open AccessArticle

In Vitro and in Vivo Evaluation of the Antioxidant and Prooxidant Activity of Phenolic Compounds Obtained from Grape (Vitis vinifera) Pomace

by Milena Cotoras, Herman Vivanco, Ricardo Melo, María Aguirre, Evelyn Silva and Leonora Mendoza

Molecules 2014, 19(12), 21154-21167; https://doi.org/10.3390/molecules191221154 - 16 Dec 2014

Cited by 79 | Viewed by 8277

Abstract

The antioxidant and/or prooxidant ability of extracts obtained from wine waste were analyzed using in vitro and in vivo assays. Cyclic voltammetry was used as the in vitro assay to determine the antioxidant and/or prooxidant properties and, the in vivo effect on mycelial [...] Read more.

The antioxidant and/or prooxidant ability of extracts obtained from wine waste were analyzed using in vitro and in vivo assays. Cyclic voltammetry was used as the in vitro assay to determine the antioxidant and/or prooxidant properties and, the in vivo effect on mycelial growth of the fungus Botrytis cinerea was evaluated. In addition, the prooxidant activity was evaluated by intracellular oxidation of compound 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA) in B. cinerea. The extracts used in this study were obtained from grape pomace of Cabernet Sauvignon, Carménère and Syrah varieties from the Misiones de Rengo Vineyard by simple extraction, using methanol/HCl 1% (v/v), ethanol 70% (v/v), or Soxhlet extraction. According to the results obtained, gallic acid was the most represented phenolic compound independent of grape variety and extraction method. In addition, vanillic acid; protocatechuic acid, syringic acid, quercetin and kaempferol were found in the extracts. From this study it was possible concluded that, depending of the method of extraction of the grape residues and the grape variety (Cabernet Sauvignon, Carménère and Syrah), the extracts showed antioxidant and/or prooxidant activity. However, no correlation can be established between the anodic oxidation potentials of the extracts and their effect on the fungus B. cinerea. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessReview

Curcumin and Inflammatory Bowel Disease: Potential and Limits of Innovative Treatments

by Liza Vecchi Brumatti, Annalisa Marcuzzi, Paola Maura Tricarico, Valentina Zanin, Martina Girardelli and Anna Monica Bianco

Molecules 2014, 19(12), 21127-21153; https://doi.org/10.3390/molecules191221127 - 16 Dec 2014

Cited by 110 | Viewed by 28216

Abstract

Curcumin belongs to the family of natural compounds collectively called curcuminoids and it possesses remarkable beneficial anti-oxidant, anti-inflammatory, anti-cancer, and neuroprotective properties. Moreover it is commonly assumed that curcumin has also been suggested as a remedy for digestive diseases such as inflammatory bowel [...] Read more.

Curcumin belongs to the family of natural compounds collectively called curcuminoids and it possesses remarkable beneficial anti-oxidant, anti-inflammatory, anti-cancer, and neuroprotective properties. Moreover it is commonly assumed that curcumin has also been suggested as a remedy for digestive diseases such as inflammatory bowel diseases (IBD), a chronic immune disorder affecting the gastrointestinal tract and that can be divided in two major subgroups: Crohn’s disease (CD) and Ulcerative Colitis (UC), depending mainly on the intestine tract affected by the inflammatory events. The chronic and intermittent nature of IBD imposes, where applicable, long-term treatments conducted in most of the cases combining different types of drugs. In more severe cases and where there has been no good response to the drugs, a surgery therapy is carried out. Currently, IBD-pharmacological treatments are generally not curative and often present serious side effects; for this reason, being known the relationship between nutrition and IBD, it is worthy of interesting the study and the development of new dietary strategy. The curcumin principal mechanism is the suppression of IBD inflammatory compounds (NF-κB) modulating immune response. This review summarizes literature data of curcumin as anti-inflammatory and anti-oxidant in IBD, trying to understand the different effects in CD e UC. Full article

(This article belongs to the Special Issue Curcumin, Inflammation, and Chronic Diseases: How are They Linked?)

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Open AccessArticle

Crystallographic Studies Evidencing the High Energy Tolerance to Disrupting the Interface Disulfide Bond of Thioredoxin 1 from White Leg Shrimp Litopenaeus vannamei

by Adam A. Campos-Acevedo and Enrique Rudiño-Piñera

Molecules 2014, 19(12), 21113-21126; https://doi.org/10.3390/molecules191221113 - 15 Dec 2014

Cited by 5 | Viewed by 6699

Abstract

Thioredoxin (Trx) is a small 12-kDa redox protein that catalyzes the reduction of disulfide bonds in proteins from different biological systems. A recent study of the crystal structure of white leg shrimp thioredoxin 1 from Litopenaeus vannamei (LvTrx) revealed a dimeric [...] Read more.

Thioredoxin (Trx) is a small 12-kDa redox protein that catalyzes the reduction of disulfide bonds in proteins from different biological systems. A recent study of the crystal structure of white leg shrimp thioredoxin 1 from Litopenaeus vannamei (LvTrx) revealed a dimeric form of the protein mediated by a covalent link through a disulfide bond between Cys73 from each monomer. In the present study, X-ray-induced damage in the catalytic and the interface disulfide bond of LvTrx was studied at atomic resolution at different transmission energies of 8% and 27%, 12.8 keV at 100 K in the beamline I-24 at Diamond Light Source. We found that at an absorbed dose of 32 MGy, the X-ray induces the cleavage of the disulfide bond of each catalytic site; however, the interface disulfide bond was cleaved at an X-ray adsorbed dose of 85 MGy; despite being the most solvent-exposed disulfide bond in LvTrx (~50 Å²). This result clearly established that the interface disulfide bond is very stable and, therefore, less susceptible to being reduced by X-rays. In fact, these studies open the possibility of the existence in solution of a dimeric LvTrx. Full article

(This article belongs to the Special Issue Sulfur Atom: Element for Adaptation to an Oxidative Environment)

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Molecules, Volume 19, Issue 12 (December 2014) – 135 articles , Pages 19253-21578

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