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Molecules, Volume 16, Issue 2 (February 2011) – 59 articles , Pages 1011-1916

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Editorial

Jump to: Research, Review

21 KiB  
Editorial
Special Issue: Nano-Catalysts and Nano-Technologies for Green Organic Synthesis
by Angelo Nacci and Nicola Cioffi
Molecules 2011, 16(2), 1452-1453; https://doi.org/10.3390/molecules16021452 - 09 Feb 2011
Cited by 9 | Viewed by 4859
Abstract
Catalysis by transition-metal nanoparticles has undergone an explosive growth during the past decade. This special issue presents the general trends in the current research in this field, the present situation concerning scope and limitations, as well as the future perspectives. Original contributions are [...] Read more.
Catalysis by transition-metal nanoparticles has undergone an explosive growth during the past decade. This special issue presents the general trends in the current research in this field, the present situation concerning scope and limitations, as well as the future perspectives. Original contributions are also presented on the applications of nano-catalysts to the green synthesis. Full article

Research

Jump to: Editorial, Review

138 KiB  
Article
Convenient Synthesis of 3,4-Dichloro-5-hydroxy-2(5H)-Furanone Glycoconjugates
by Edyta Gondela and Krzysztof Z. Walczak
Molecules 2011, 16(2), 1011-1020; https://doi.org/10.3390/molecules16021011 - 25 Jan 2011
Cited by 5 | Viewed by 5866
Abstract
3,4-Dichloro-5-hydroxy-2(5H)-furanone treated with methyl chloroformate in the presence of diisopropylethylamine (Hünig’s base) gave the corresponding carbonate. The labile methoxycarbonyloxy group smoothly undergoes substitution by amino alcohols. The obtained 5-(w-hydroxyalkylamino) mucochloric acid derivatives reacted with peracetylated glucals using triphenylphosphine hydrobromide as a [...] Read more.
3,4-Dichloro-5-hydroxy-2(5H)-furanone treated with methyl chloroformate in the presence of diisopropylethylamine (Hünig’s base) gave the corresponding carbonate. The labile methoxycarbonyloxy group smoothly undergoes substitution by amino alcohols. The obtained 5-(w-hydroxyalkylamino) mucochloric acid derivatives reacted with peracetylated glucals using triphenylphosphine hydrobromide as a catalyst to give the title muchloric acid glycoconjugates. Full article
(This article belongs to the Special Issue Glycosides)
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295 KiB  
Article
Comparative Anti-Infectious Bronchitis Virus (IBV) Activity of (-)-Pinene: Effect on Nucleocapsid (N) Protein
by Zhiwei Yang, Nan Wu, Yuangang Zu and Yujie Fu
Molecules 2011, 16(2), 1044-1054; https://doi.org/10.3390/molecules16021044 - 25 Jan 2011
Cited by 43 | Viewed by 9778
Abstract
In the present study, anti-IBV (infectious bronchitis virus) activities of (-)-pinenes were studied by MTT assay, as well as docking and molecular dynamic (MD) simulations. The CC50 values of (-)-α-pinene and (-)-β-pinene were above 10 mM. And the maximum noncytotoxic concentrations (TD [...] Read more.
In the present study, anti-IBV (infectious bronchitis virus) activities of (-)-pinenes were studied by MTT assay, as well as docking and molecular dynamic (MD) simulations. The CC50 values of (-)-α-pinene and (-)-β-pinene were above 10 mM. And the maximum noncytotoxic concentrations (TD0) of (-)-α-pinene and (-)-β-pinene were determined as 7.88 ± 0.06 and 6.09 ± 0.31 mM, respectively. The two compounds were found to inhibit IBV with an IC50 of 0.98 ± 0.25 and 1.32 ± 0.11 mM. The MTT assay showed that the inhibitions of (-)-pinenes against IBV appear to occur moderately before entering the cell but are much stronger occur after penetration of the virus into the cell. Molecular simulations indicated that (-)-α-pinene and (-)-β-pinene specifically interact with the active site which is located at the N terminus of phosphorylated nucleocapsid (N) protein, with the former being more potent than the latter. The binding energies of them are −36.83 and −35.59 kcal mol−1, respectively. Results presented here may suggest that (-)-α-pinene and (-)-β-pinene possess anti-IBV properties, and therefore are a potential source of anti-IBV ingredients for the pharmaceutical industry. Full article
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274 KiB  
Article
Antioxidant Activity of β-Carotene Compounds in Different in Vitro Assays
by Lars Mueller and Volker Boehm
Molecules 2011, 16(2), 1055-1069; https://doi.org/10.3390/molecules16021055 - 25 Jan 2011
Cited by 160 | Viewed by 14591
Abstract
β-Carotene (BC) is the most abundant carotenoid in human diet, almost solely as (all-E)-isomer. Significant amounts of (Z)-isomers of BC are present in processed food as well as in mammalian tissues. Differences are described for the activity of various [...] Read more.
β-Carotene (BC) is the most abundant carotenoid in human diet, almost solely as (all-E)-isomer. Significant amounts of (Z)-isomers of BC are present in processed food as well as in mammalian tissues. Differences are described for the activity of various BC isomers in forming retinal and protecting against cancer and cardiovascular diseases. Eccentric cleavage of BC leads to degradation products such as carotenals. A variety of negative consequences were published for the non-vitamin A active BC metabolites, such as inducing the carcinogenesis of benzo[a]pyrene, impairing mitochondrial function, or increasing CYP activity. To increase the knowledge on the antioxidant activity, a variety of BC isomers and metabolites were tested in various in vitro assays.In the present study, no ferric reducing activity (FRAP assay) was observed for the BC isomers. Between the major BC isomers (all-E, 9Z, and 13Z) no significant differences in bleaching the ABTS●+ (αTEAC assay) or in scavenging peroxyl radicals (ROO) generated by thermal degradation of AAPH (using a chemiluminescence assay) were detected. However, the (15Z)-isomer was less active, maybe due to its low stability. The degradation to β-apo-carotenoids increased FRAP activity and ROO scavenging activity compared to the parent molecule. Dependence on chain length and character of the terminal function was determined in αTEAC assay with following order of increasing activity: β-apo-8’-carotenal Full article
(This article belongs to the Section Natural Products Chemistry)
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221 KiB  
Article
Irving-Williams Order in the Framework of Connectivity Index 3χv Enables Simultaneous Prediction of Stability Constants of Bivalent Transition Metal Complexes
by Ante Miličević, Gina Branica and Nenad Raos
Molecules 2011, 16(2), 1103-1112; https://doi.org/10.3390/molecules16021103 - 26 Jan 2011
Cited by 29 | Viewed by 10625
Abstract
Logarithms of stability constants, log K1 and log β2, of the first transition series metal mono- and bis-complexes with any of four aliphatic amino acids (glycine, alanine, valine and leucine) decrease monotonously with third order valence connectivity index, [...] Read more.
Logarithms of stability constants, log K1 and log β2, of the first transition series metal mono- and bis-complexes with any of four aliphatic amino acids (glycine, alanine, valine and leucine) decrease monotonously with third order valence connectivity index, 3χv, from Cu2+ to Mn2+. While stability of the complexes with the same metal is linearly dependent on 3χv, stability constants of Mn2+, Fe2+, Co2+, and Ni2+complexes with the same ligand show a quadratic dependence on 3χv. As Cu2+ complexes deviate significantly from quadratic functions, models for the simultaneous estimation of the stability constants, yielding r = 0.999 (S.E. = 0.05) and r = 0.998 (S.E. = 0.11), for log K1 and log β2, respectively, were developed only for Mn2+, Fe2+, Co2+, and Ni2+ complexes with amino acids. Full article
(This article belongs to the Special Issue Organometallic Chemistry)
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236 KiB  
Article
Synthesis and Anti-Fungal Activity of Seven Oleanolic Acid Glycosides
by Hanqing Zhao, Guanghui Zong, Jianjun Zhang, Daoquan Wang and Xiaomei Liang
Molecules 2011, 16(2), 1113-1128; https://doi.org/10.3390/molecules16021113 - 26 Jan 2011
Cited by 12 | Viewed by 8155
Abstract
In order to develop potential anti-fungal agents, seven glycoconjugates composed of a-L-rhamnose, 6-deoxy-a-L-talose, b-D-galactose, a-D-mannose, b-D-xylose-(1®4)-6-deoxy-a-L-talose, b-D-galactose-(1®4)-a-L-rhamnose, b-D-galactose-(1®3)-b-D-xylose-(1®4)-6-deoxy-a-L-talose as the glycone and oleanolic acid as the aglycone were synthesized in an efficient and practical way using glycosyl trichloroacetimidates as donors. The structures of [...] Read more.
In order to develop potential anti-fungal agents, seven glycoconjugates composed of a-L-rhamnose, 6-deoxy-a-L-talose, b-D-galactose, a-D-mannose, b-D-xylose-(1®4)-6-deoxy-a-L-talose, b-D-galactose-(1®4)-a-L-rhamnose, b-D-galactose-(1®3)-b-D-xylose-(1®4)-6-deoxy-a-L-talose as the glycone and oleanolic acid as the aglycone were synthesized in an efficient and practical way using glycosyl trichloroacetimidates as donors. The structures of the new compounds were confirmed by MS, 1H-NMR and 13C- NMR. Preliminary studies based on means of mycelium growth rate, indicated that all the compounds possess certain fungicidal activity against Sclerotinia sclerotiorum (Lib.) de Bary, Rhizoctonia solani Kuhn, Botrytis cinerea Pers and Phytophthora parasitica Dast. Full article
(This article belongs to the Special Issue Glycosides)
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129 KiB  
Article
Antitrypanosomal Activity of Novel Benzaldehyde-Thiosemicarbazone Derivatives from Kaurenoic Acid †
by Shirani K. Haraguchi, Adriano A. Silva, Gentil J. Vidotti, Phercyles V. Dos Santos, Francielle P. Garcia, Raissa B. Pedroso, Celso V. Nakamura, Cecília M. A. De Oliveira and Cleuza C. Da Silva
Molecules 2011, 16(2), 1166-1180; https://doi.org/10.3390/molecules16021166 - 26 Jan 2011
Cited by 45 | Viewed by 10096
Abstract
A series of new thiosemicarbazones derived from natural diterpene kaurenoic acid were synthesized and tested against the epimastigote forms of Trypanosoma cruzi to evaluate their antitrypanosomal potential. Seven of the synthesized thiosemicarbazones were more active than kaurenoic acid with IC50 values between [...] Read more.
A series of new thiosemicarbazones derived from natural diterpene kaurenoic acid were synthesized and tested against the epimastigote forms of Trypanosoma cruzi to evaluate their antitrypanosomal potential. Seven of the synthesized thiosemicarbazones were more active than kaurenoic acid with IC50 values between 2-24.0 mM. The o-nitro-benzaldehyde-thiosemicarbazone derivative was the most active compound with IC50 of 2.0 mM. The results show that the structural modifications accomplished enhanced the antitrypanosomal activity of these compounds. Besides, the thiocyanate, thiosemicarbazide and the p- methyl, p-methoxy, p-dimethylamine, m-nitro and o-chlorobenzaldehyde-thiosemicarbazone derivatives displayed lower toxicity for LLMCK2 cells than kaurenoic acid, exhibing an IC50 of 59.5 mM. Full article
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256 KiB  
Article
Seasonal Variation in the Chemical Composition and Antimicrobial Activity of Volatile Oils of Three Species of Leptospermum (Myrtaceae) Grown in Brazil
by Antonio Jacinto Demuner, Luiz Claudio Almeida Barbosa, Cassia Gonçalves Magalhaes, Cleber Jose Da Silva, Celia Regina Alvares Maltha and Antonio Lelis Pinheiro
Molecules 2011, 16(2), 1181-1191; https://doi.org/10.3390/molecules16021181 - 26 Jan 2011
Cited by 71 | Viewed by 10078
Abstract
This study investigates the seasonal variation of three species of Leptospermum (Myrtaceae) grown in Brazil. The chemical composition of the volatile oils of L. flavescens and L. petersonii did not show any significant seasonal variation in the major components, while for Leptospermum madidum [...] Read more.
This study investigates the seasonal variation of three species of Leptospermum (Myrtaceae) grown in Brazil. The chemical composition of the volatile oils of L. flavescens and L. petersonii did not show any significant seasonal variation in the major components, while for Leptospermum madidum subsp. sativum the levels of major constituents of the volatile oils varied with the harvest season. Major fluctuations in the composition of L. madidum subsp. sativum oil included α-pinene (0–15.2%), β-pinene (0.3–18.5%), α-humulene (0.8–30%), 1,8-cineole (0.4–7.1%) and E-caryophyllene (0.4–11.9%). Levels of β-pinene (0.3–5.6%), terpinen-4-ol (4.7–7.2%) and nerolidol (55.1–67.6%) fluctuated seasonally in the L. flavescens oil. In L. petersonii, changes were noted for geranial (29.8–32.8%), citronellal (26.5–33.9%) and neral (22.7–23.5%). The activity of the volatile oils against the tested bacteria differed, depending on season the oils were obtained. In general, the volatile oils were more active against Gram-positive bacteria. Full article
257 KiB  
Article
Crystal Structure and Hydrogen Bonding Study of (10E)-2,2-Dimethyl-3,4-dihydro-2H-benzo[g]chromene-5,10-dione 10-Oxime Derived From a-Lapachone
by Andrea R. Da Silva, Marcelo H. Herbst, Aurelio B. B. Ferreira, Ari M. Da Silva and Lorenzo C. Visentin
Molecules 2011, 16(2), 1192-1200; https://doi.org/10.3390/molecules16021192 - 27 Jan 2011
Cited by 4 | Viewed by 9672
Abstract
The compound (10E)-2,2-dimethyl-3,4-dihydro-2H-benzo[g]chromene-5,10-dione-10-oxime (1) was synthesized from a-lapachone and hydroxylamine chloride in alkaline medium. Single-crystals suitable for X-ray diffraction measurements were grown from an ethanol solution, and the crystal structure of the title molecule is reported for the first [...] Read more.
The compound (10E)-2,2-dimethyl-3,4-dihydro-2H-benzo[g]chromene-5,10-dione-10-oxime (1) was synthesized from a-lapachone and hydroxylamine chloride in alkaline medium. Single-crystals suitable for X-ray diffraction measurements were grown from an ethanol solution, and the crystal structure of the title molecule is reported for the first time. The title molecule was also characterized by 1H- and 13C-NMR in CDCl3 solution, FTIR and MS. The crystal structure of 1 shows an E stereochemistry and dimers formed through classical hydrogen bonds. Full article
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194 KiB  
Article
Preparative Isolation of Three Anthraquinones from Rumex japonicus by High-Speed Counter-Current Chromatography
by Shuying Guo, Bo Feng, Ruonan Zhu, Jiankang Ma and Wei Wang
Molecules 2011, 16(2), 1201-1210; https://doi.org/10.3390/molecules16021201 - 27 Jan 2011
Cited by 57 | Viewed by 8110
Abstract
Three anthraquinones—emodin, chrysophanol, and physcion—were successfully purified from the dichloromethane extract of the Chinese medicinal herb Rumex japonicus by high-speed counter-current chromatography (HSCCC). The extract was separated with n-hexane–ethanol–water (18:22:3, v/v/v) as the two-phase solvent system and yielded 3.4 mg of emodin, [...] Read more.
Three anthraquinones—emodin, chrysophanol, and physcion—were successfully purified from the dichloromethane extract of the Chinese medicinal herb Rumex japonicus by high-speed counter-current chromatography (HSCCC). The extract was separated with n-hexane–ethanol–water (18:22:3, v/v/v) as the two-phase solvent system and yielded 3.4 mg of emodin, 24.1 mg of chrysophanol, and 2.0 mg of physcion from 500 mg of sample with purities of 99.2 %, 98.8% and 98.2%, respectively. The HSCCC fractions were analyzed by high-performance liquid chromatography (HPLC) and the chemical structures of the three anthraquinones were confirmed by 1H-NMR and 13C-NMR analysis. This is the first time these anthraquinones have been obtained from R. japonicus by HSCCC. Full article
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1242 KiB  
Article
Selection of Peptides Targeting Helix 31 of Bacterial 16S Ribosomal RNA by Screening M13 Phage-Display Libraries
by Tek N. Lamichhane, N. Dinuka Abeydeera, Anne-Cécile E. Duc, Philip R. Cunningham and Christine S. Chow
Molecules 2011, 16(2), 1211-1239; https://doi.org/10.3390/molecules16021211 - 28 Jan 2011
Cited by 22 | Viewed by 8943
Abstract
Ribosomal RNA is the catalytic portion of ribosomes, and undergoes a variety of conformational changes during translation. Structural changes in ribosomal RNA can be facilitated by the presence of modified nucleotides. Helix 31 of bacterial 16S ribosomal RNA harbors two modified nucleotides, m [...] Read more.
Ribosomal RNA is the catalytic portion of ribosomes, and undergoes a variety of conformational changes during translation. Structural changes in ribosomal RNA can be facilitated by the presence of modified nucleotides. Helix 31 of bacterial 16S ribosomal RNA harbors two modified nucleotides, m2G966 and m5C967, that are highly conserved among bacteria, though the degree and nature of the modifications in this region are different in eukaryotes. Contacts between helix 31 and the P-site tRNA, initiation factors, and ribosomal proteins highlight the importance of this region in translation. In this work, a heptapeptide M13 phage-display library was screened for ligands that target the wild-type, naturally modified bacterial helix 31. Several peptides, including TYLPWPA, CVRPFAL, TLWDLIP, FVRPFPL, ATPLWLK, and DIRTQRE, were found to be prevalent after several rounds of screening. Several of the peptides exhibited moderate affinity (in the high nM to low µM range) to modified helix 31 in biophysical assays, including surface plasmon resonance (SPR), and were also shown to bind 30S ribosomal subunits. These peptides also inhibited protein synthesis in cell-free translation assays. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
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409 KiB  
Article
Tannin Fingerprinting in Vegetable Tanned Leather by Solid State NMR Spectroscopy and Comparison with Leathers Tanned by Other Processes
by Frederik H. Romer, Andrew P. Underwood, Nadine D. Senekal, Susan L. Bonnet, Melinda J. Duer, David G. Reid and Jan H. Van der Westhuizen
Molecules 2011, 16(2), 1240-1252; https://doi.org/10.3390/molecules16021240 - 28 Jan 2011
Cited by 34 | Viewed by 10257
Abstract
Solid state 13C-NMR spectra of pure tannin powders from four different sources – mimosa, quebracho, chestnut and tara – are readily distinguishable from each other, both in pure commercial powder form, and in leather which they have been used to tan. Groups [...] Read more.
Solid state 13C-NMR spectra of pure tannin powders from four different sources – mimosa, quebracho, chestnut and tara – are readily distinguishable from each other, both in pure commercial powder form, and in leather which they have been used to tan. Groups of signals indicative of the source, and type (condensed vs. hydrolyzable) of tannin used in the manufacture are well resolved in the spectra of the finished leathers. These fingerprints are compared with those arising from leathers tanned with other common tanning agents. Paramagnetic chromium (III) tanning causes widespread but selective disappearance of signals from the spectrum of leather collagen, including resonances from acidic aspartyl and glutamyl residues, likely bound to Cr (III) structures. Aluminium (III) and glutaraldehyde tanning both cause considerable leather collagen signal sharpening suggesting some increase in molecular structural ordering. The 27Al-NMR signal from the former material is consistent with an octahedral coordination by oxygen ligands. Solid state NMR thus provides easily recognisable reagent specific spectral fingerprints of the products of vegetable and some other common tanning processes. Because spectra are related to molecular properties, NMR is potentially a powerful tool in leather process enhancement and quality or provenance assurance. Full article
(This article belongs to the Special Issue Tannins)
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204 KiB  
Article
Synthesis, Characterization and Antifungal Evaluation of 5-Substituted-4-Amino-1,2,4-Triazole-3-Thioesters
by Aurangzeb Hasan, Noel Francis Thomas and Shelly Gapil
Molecules 2011, 16(2), 1297-1309; https://doi.org/10.3390/molecules16021297 - 28 Jan 2011
Cited by 37 | Viewed by 8899
Abstract
A series of 5-substituted-4-amino-1,2,4-triazole-3-thioesters was synthesized by converting variously substituted organic acids successively into the corresponding esters, hydrazides, 5-substituted-1,3,4-oxadiazole-2-thiols, 5-substituted-1,2,4-triazole-2-thiols and 5-substituted-1,3,4-oxadiazole-2-thioesters. Finally the target compounds were obtained by refluxing 5-substituted-1,3,4-oxadiazole-2-thioesters in the presence of hydrazine hydrate and absolute alcohol. The structures of [...] Read more.
A series of 5-substituted-4-amino-1,2,4-triazole-3-thioesters was synthesized by converting variously substituted organic acids successively into the corresponding esters, hydrazides, 5-substituted-1,3,4-oxadiazole-2-thiols, 5-substituted-1,2,4-triazole-2-thiols and 5-substituted-1,3,4-oxadiazole-2-thioesters. Finally the target compounds were obtained by refluxing 5-substituted-1,3,4-oxadiazole-2-thioesters in the presence of hydrazine hydrate and absolute alcohol. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The synthesized compounds were evaluated for their in vitro antifungal activity. Some of the evaluated compounds possessed significant antifungal activity as compared to a terbinafine standard. Full article
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355 KiB  
Article
Triterpene Composition and Bioactivities of Centella asiatica
by Puziah Hashim, Hamidah Sidek, Mohd Helme M. Helan, Aidawati Sabery, Uma Devi Palanisamy and Mohd Ilham
Molecules 2011, 16(2), 1310-1322; https://doi.org/10.3390/molecules16021310 - 28 Jan 2011
Cited by 194 | Viewed by 21782
Abstract
Leaves of Centella asiatica (Centella) were analysed for their triterpene composition and bioactivity such as collagen enhancement, antioxidant, anticellulite and UV protection capacity properties. Triterpenes of Centella were measured using HPLC-PAD on an Excil ODS 5 mm (C18) column for the simultaneous determination [...] Read more.
Leaves of Centella asiatica (Centella) were analysed for their triterpene composition and bioactivity such as collagen enhancement, antioxidant, anticellulite and UV protection capacity properties. Triterpenes of Centella were measured using HPLC-PAD on an Excil ODS 5 mm (C18) column for the simultaneous determination of asiatic acid, madecassic acid, asiaticoside and madecassoside. Centella was found to contain significant amounts of madecassoside (3.10 ± 4.58 mg/mL) and asiaticoside (1.97 ± 2.65 mg/mL), but was low in asiatic and madecassic acid. The highest collagen synthesis was found at 50 mg/mL of Centella extracts. The antioxidant activity of Centella (84%) was compared to grape seed extract (83%) and Vitamin C (88%). Its lipolytic activity was observed by the release of glycerol (115.9 µmol/L) at 0.02% concentration. Centella extracts exhibited similar UV protection effect to OMC at 10% concentration. In view of these results, the potential application of Centella in food and pharmaceutical industries is now widely open. Full article
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4529 KiB  
Article
Behaviors in Ethylene Polymerization of MgCl2-SiO2/TiCl4/THF Ziegler-Natta Catalysts with Differently Treated SiO2
by Nichapat Senso, Bunjerd Jongsomjit and Piyasan Praserthdam
Molecules 2011, 16(2), 1323-1335; https://doi.org/10.3390/molecules16021323 - 28 Jan 2011
Cited by 8 | Viewed by 7295
Abstract
The present research focuses on investigation of the catalytic behaviors of MgCl2-SiO2/TiCl4/THF Ziegler-Natta (ZN) catalysts with fumed SiO2 variously treated with silane compounds. The non-treated silica (NTS) and other silicas treated with dimethylsilicone fluid (TSDMSF), dimethyldichlorosilane [...] Read more.
The present research focuses on investigation of the catalytic behaviors of MgCl2-SiO2/TiCl4/THF Ziegler-Natta (ZN) catalysts with fumed SiO2 variously treated with silane compounds. The non-treated silica (NTS) and other silicas treated with dimethylsilicone fluid (TSDMSF), dimethyldichlorosilane (TSDMDCS), and hexamethyl-disilazane (TSHMDS) were employed. It was found that the Cat-TSDMDCS and Cat-TSHMDS exhibited remarkably high activity, even with a similar bulk Ti content as the others. Thus, the more powerful technique of XPS analysis was used to determine the Ti content at the catalyst surface. It was evident that the surface concentrations of Ti could play important role on the catalyst activity. As the result, the increased activity is proportional to the surface concentration of Ti. It was mentioned that the change in surface concentration of Ti with different treated silica can be attributed to the effect of silane spacer group and steric hindrance. The distribution of Ti on the external surface can be also proven by means of EDX mapping, which matched the results obtained by XPS analysis. The treated silica also resulted in narrower molecular weight distribution (MWD) due to the more uniform active sites produced. There was no significant change in polymer morphology upon treatment of the silica. Full article
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301 KiB  
Article
Role of Intestinal Hydrolase in the Absorption of Prenylated Flavonoids Present in Yinyanghuo
by Yan Chen, Jinyan Wang, Xiaobin Jia, Xiaobin Tan and Ming Hu
Molecules 2011, 16(2), 1336-1348; https://doi.org/10.3390/molecules16021336 - 01 Feb 2011
Cited by 67 | Viewed by 9446
Abstract
Purpose: Yinyanghuo (Herba Epimdii) is a traditional Chinese herb containing prenylated flavonoids as its active constituents. The aim of this study was to examine the significance of the intestinal hydrolysis of prenylated flavonoids by lactase phlorizin hydrolase (LPH), an enzyme at the [...] Read more.
Purpose: Yinyanghuo (Herba Epimdii) is a traditional Chinese herb containing prenylated flavonoids as its active constituents. The aim of this study was to examine the significance of the intestinal hydrolysis of prenylated flavonoids by lactase phlorizin hydrolase (LPH), an enzyme at the brush border membrane of intestinal cells. Methods: A four-site perfused rat intestinal model was used. The concentration of the flavonoids of interest and their metabolites in different intestinal segements were analyzed by HPLC, and the apparent permeabilities were calculated. A lactase phlorizin hydrolase inhibitor (gluconolactone) was employed to investigate the mechanism of the intestinal absorption, and the metabolites of the four flavonoids were identified using LC/MS/MS. Results: Diglycosides (icariin) or triglycosides (epimedin A, epimedin B, and epimedin C) were hydrolyzed rapidly in duodenum and jejunum producing one or two metabolites, while a monoglycoside (baohuoside I) was absorbed directly. When co-perfused with glucono-lactone, both the hydrolysis of diglycosides and triglycosides were significantly inhibited, with inhibition rates for icariin (62%, 50%, 40%, 46%), epimedin A, (55%, 26%, 21%, 14%); epimedin B (42%, 40%, 74%, 22%), and epimedin C (42%, 40%, 52%, 35%) in duodenum, jejunum, ileum, and colon, respectively. Also the metabolites of icariin, epimedin A, epimedin B, and epimedin C were identified as baohuoside I (one of two), sagittatoside A, sagittatoside B, and 2"-O-rhamnosylicariside II, respectively. Conclusions: The results showed that lactase phlorizin hydrolase was a major determinant of the intestinal absorption of prenylated flavonoids present in Yinyanghuo. Full article
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720 KiB  
Article
Determination of Ascorbic Acid Content of Some Fruit Juices and Wine by Voltammetry Performed at Pt and Carbon Paste Electrodes
by Aurelia Magdalena Pisoschi, Aneta Pop, Gheorghe Petre Negulescu and Aurel Pisoschi
Molecules 2011, 16(2), 1349-1365; https://doi.org/10.3390/molecules16021349 - 01 Feb 2011
Cited by 77 | Viewed by 12033
Abstract
A method was developed for assessing ascorbic acid concentration in fruit juices and wine by differential pulse voltammetry. The oxidation peak for ascorbic acid occurs at about 530 mV (versus SCE) on a Pt strip working electrode and at about 470 mV on [...] Read more.
A method was developed for assessing ascorbic acid concentration in fruit juices and wine by differential pulse voltammetry. The oxidation peak for ascorbic acid occurs at about 530 mV (versus SCE) on a Pt strip working electrode and at about 470 mV on a carbon paste working electrode. The influence of the operational parameters like the pulse amplitude and the pulse period on the analytical signal was investigated. The obtained calibration graph shows a linear dependence between the peak height and ascorbic acid concentration within the range 0.31-20 mM with a Pt working electrode, and within the range 0.07-20 mM with a carbon paste working electrode. The equation of the calibration graph was y = 21.839x + 35.726, r2 = 0.9940, when a Pt strip electrode was used (where y represents the value of the current intensity measured for the peak height, expressed as µA and x the analyte concentration, as mM). R.S.D. = 2.09%, n = 10, Cascorbic acid = 2.5 mM. The equation of the calibration graph was y = 3.4429x + 5.7334, r2 = 0.9971, when a carbon paste electrode was used (where y represents the value of intensity measured for the peak height, expressed as µA and x the analyte concentration, as mM). R.S.D. = 2.35%, n = 10, Cascorbic acid = 2.5 mM. The developed method was applied to ascorbic acid assessment in fruit juices and wine. The ascorbic acid content determined ranged between 6.83 mg/100 mL juice for soft drinks (Fanta Madness) and 54.74 mg/100 mL for citrus (lemon) juices obtained by squeezing fruit. Different ascorbic acid concentrations (from standard solutions) were added to the analysed samples, the degree of recovery being comprised between 94.74 and 104.97%. The results of ascorbic acid assessment by differential pulse voltammetry were compared with those obtained by cyclic voltammetry. The results obtained by the two methods were in good agreement. Full article
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223 KiB  
Article
Chemical Composition, Antimicrobial and Antioxidant Activities of Essential Oils from Organically Cultivated Fennel Cultivars
by Abdelaaty A. Shahat, Abeer Y. Ibrahim, Saber F. Hendawy, Elsayed A. Omer, Faiza M. Hammouda, Fawzia H. Abdel-Rahman and Mahmoud A. Saleh
Molecules 2011, 16(2), 1366-1377; https://doi.org/10.3390/molecules16021366 - 01 Feb 2011
Cited by 181 | Viewed by 17456
Abstract
Essential oils of the fruits of three organically grown cultivars of Egyptian fennel (Foeniculum vulgare var. azoricum, Foeniculum vulgare var. dulce and Foeniculum vulgare var. vulgare) were examined for their chemical constituents, antimicrobial and antioxidant activities. Gas chromatography/mass spectrometry analysis [...] Read more.
Essential oils of the fruits of three organically grown cultivars of Egyptian fennel (Foeniculum vulgare var. azoricum, Foeniculum vulgare var. dulce and Foeniculum vulgare var. vulgare) were examined for their chemical constituents, antimicrobial and antioxidant activities. Gas chromatography/mass spectrometry analysis of the essential oils revealed the presence of 18 major monoterpenoids in all three cultivars but their percentage in each oil were greatly different. trans-Anethole, estragole, fenchone and limonene were highly abundant in all of the examined oils. Antioxidant activities of the essential oils were evaluated using the DPPH radical scavenging, lipid peroxidation and metal chelating assays. Essential oils from the azoricum and dulce cultivars were more effective antioxidants than that from the vulgare cultivar. Antimicrobial activities of each oil were measured against two species of fungi, two species of Gram negative and two species of Gram positive bacteria. All three cultivars showed similar antimicrobial activity. Full article
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194 KiB  
Article
Effects of Rutin and Hesperidin and Their Al(III) and Cu(II) Complexes on in Vitro Plasma Coagulation Assays
by Vesna Kuntić, Ivana Filipović and Zorica Vujić
Molecules 2011, 16(2), 1378-1388; https://doi.org/10.3390/molecules16021378 - 07 Feb 2011
Cited by 69 | Viewed by 10391
Abstract
Two flavonoids, rutin and hesperidin, were investigated in vitro for anticoagulant activity through coagulation tests: activated partial thromboplastin time (aPTT), prothrombin time (PT) and thrombin time (TT). Only an ethanolic solution of rutin at the concentration of 830 µM prolonged aPTT, while TT [...] Read more.
Two flavonoids, rutin and hesperidin, were investigated in vitro for anticoagulant activity through coagulation tests: activated partial thromboplastin time (aPTT), prothrombin time (PT) and thrombin time (TT). Only an ethanolic solution of rutin at the concentration of 830 µM prolonged aPTT, while TT and PT were unaffected. In order to evaluate whether the prolongation of aPTT was due to the decrease of coagulation factors, the experiment with deficient plasma was performed, showing the effects on factors VIII and IX. Since pharmacological activity of flavonoids is believed to increase when they are coordinated with metal ions, complexes of these flavonoids with Al(III) and Cu(II) ions were also tested. The results showed that complexes significantly prolonged aPTT and had no effects on PT and TT. Assay with deficient plasma (plasma having the investigated factor at less then 1%) revealed that complexes could bind to the coagulation factors, what may lead to a non-specific inhibition and aPTT prolongation. An effort was made to correlate stability of complexes with their anticoagulant properties. Full article
(This article belongs to the Section Molecular Diversity)
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478 KiB  
Article
New Hydrophilic/Lipophilic Tetra-α-(4-carboxyphenoxy) Phthalocyanine Zinc-Mediated Photodynamic Therapy Inhibits the Proliferation of Human Hepatocellular Carcinoma Bel-7402 Cells by Triggering Apoptosis and Arresting Cell Cycle
by Chunhui Xia, Yu Wang, Wei Chen, Wenxue Yu, Baiqi Wang and Tao Li
Molecules 2011, 16(2), 1389-1401; https://doi.org/10.3390/molecules16021389 - 07 Feb 2011
Cited by 22 | Viewed by 9107
Abstract
Photodynamic therapy (PDT) is a novel and promising antitumor treatment. Phthalocyanine-mediated PDT has shown antitumor activity in some tumor cells, but the effect of new hydrophilic/lipophilic tetra-α-(4-carboxyphenoxy)phthalocyanine zinc (TαPcZn)-mediated PDT (TαPcZn-PDT) on human hepatocellular carcinoma Bel-7402 cells and underlying mechanisms have not been [...] Read more.
Photodynamic therapy (PDT) is a novel and promising antitumor treatment. Phthalocyanine-mediated PDT has shown antitumor activity in some tumor cells, but the effect of new hydrophilic/lipophilic tetra-α-(4-carboxyphenoxy)phthalocyanine zinc (TαPcZn)-mediated PDT (TαPcZn-PDT) on human hepatocellular carcinoma Bel-7402 cells and underlying mechanisms have not been clarified. In the present study, therefore, the ultraviolet-visible (UV-vis) absorption spectrum and cellular localization of TαPcZn, and effect of TαPcZn-PDT on the proliferation, apoptosis, cell cycle, Bcl-2 and Fas in Bel-7402 cells were investigated by spectrophotometry, inverted microscope, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, electron microscopy, annexinV-FITC/propidium iodide double staining, DNA content and immunoblot assay, respectively. We found that an intense absorption in UV-vis absorption spectrum of TαPcZn was in the red visible region at 650–680 nm, where light penetration in tissue is efficient, that green TαPcZn localized to both plasma membrane and nuclear membrane of Bel-7402 cells, signifying that there was a selective uptake of TαPcZn in Bel-7402 cells and TαPcZn-PDT would be expected to directly damage DNA, and that TαPcZn-PDT significantly resulted in the proliferation inhibition, apoptosis induction, S cell cycle arrest, and down-regulation of Bcl-2 and Fas. Taken together, we conclude that TαPcZn-PDT inhibits the proliferation of Bel-7402 cells by triggering apoptosis and arresting the cell cycle. Full article
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152 KiB  
Article
Two New Phenols from Scutellaria barbata
by Gang Wang, Fei Wang and Ji-Kai Liu
Molecules 2011, 16(2), 1402-1408; https://doi.org/10.3390/molecules16021402 - 07 Feb 2011
Cited by 11 | Viewed by 5991
Abstract
Two new phenols, 2(S)-2’,7-dihydroxy-5,8-dimethoxyflavanone (1) and (S)-2-(4-hydroxyphenyl)-6-methyl-2,3-dihydro-4H-pyran-4-one (2), were isolated from the ethanol extract of Scutellaria barbata. Their structures were elucidated on the basis of spectroscopic analysis. Full article
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291 KiB  
Article
Enhancement of Copper Availability and Microbial Community Changes in Rice Rhizospheres Affected by Sulfur
by Ji-Yan Shi, Hui-Rong Lin, Xiao-Feng Yuan, Xin-Cai Chen, Chao-Feng Shen and Ying-Xu Chen
Molecules 2011, 16(2), 1409-1417; https://doi.org/10.3390/molecules16021409 - 07 Feb 2011
Cited by 38 | Viewed by 7105
Abstract
The role of sulfur on the availability of Cu and the bacterial community in rice rhizospheres was investigated by pot experiments. With sulfur addition, pH in rhizosphere soil decreased and Mg(NO3)2 extractable Cu increased significantly. The bacterial community composition also [...] Read more.
The role of sulfur on the availability of Cu and the bacterial community in rice rhizospheres was investigated by pot experiments. With sulfur addition, pH in rhizosphere soil decreased and Mg(NO3)2 extractable Cu increased significantly. The bacterial community composition also changed with sulfur addition. Some specific clones having high similarity to Thiobacillus, which indicated that sulfur oxidation in the rice rhizosphere could increase the availability of Cu. These results suggested that sulfur source which could provide substrate to sulfur oxidizing bacteria and enhance the availability of Cu was not a suitable sulfur fertilizer for Cu polluted soil. Full article
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165 KiB  
Article
A Convenient and Safe O-Methylation of Flavonoids with Dimethyl Carbonate (DMC)
by Roberta Bernini, Fernanda Crisante and Maria Cristina Ginnasi
Molecules 2011, 16(2), 1418-1425; https://doi.org/10.3390/molecules16021418 - 09 Feb 2011
Cited by 59 | Viewed by 14050
Abstract
Dietary flavonoids exhibit beneficial health effects. Several epidemiological studies have focused on their biological activities, including antioxidant, antibacterial, antiviral, anti-inflammatory and cardiovascular properties. More recently, these compounds have shown to be promising cancer chemopreventive agents in cell culture studies. In particular, O-methylated [...] Read more.
Dietary flavonoids exhibit beneficial health effects. Several epidemiological studies have focused on their biological activities, including antioxidant, antibacterial, antiviral, anti-inflammatory and cardiovascular properties. More recently, these compounds have shown to be promising cancer chemopreventive agents in cell culture studies. In particular, O-methylated flavonoids exhibited a superior anticancer activity than the corresponding hydroxylated derivatives being more resistant to the hepatic metabolism and showing a higher intestinal absorption. In this communication we describe a convenient and efficient procedure in order to prepare a large panel of mono- and dimethylated flavonoids by using dimethyl carbonate (DMC), an ecofriendly and non toxic chemical, which plays the role of both solvent and reagent. In order to promote the methylation reaction under mild and practical conditions, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was added in the solution; methylated flavonoids were isolated in high yields and with a high degree of purity. This methylation protocol avoids the use of hazardous and high toxic reagents (diazomethane, dimethyl sulfate, methyl iodide). Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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488 KiB  
Article
Antioxidant Activities and Polyphenolic Contents of Three Selected Micromeria Species from Croatia
by Sanda Vladimir-Knežević, Biljana Blažeković, Maja Bival Štefan, Antun Alegro, Tamás Kőszegi and József Petrik
Molecules 2011, 16(2), 1454-1470; https://doi.org/10.3390/molecules16021454 - 10 Feb 2011
Cited by 122 | Viewed by 11021
Abstract
Antioxidant activities of three selected Micromeria species growing in Croatia (M. croatica, M. juliana and M. thymifolia) were evaluated using five different antioxidant assays, in comparison with plant polyphenolic constituents and reference antioxidants. All studied ethanolic extracts exhibited considerable activity [...] Read more.
Antioxidant activities of three selected Micromeria species growing in Croatia (M. croatica, M. juliana and M. thymifolia) were evaluated using five different antioxidant assays, in comparison with plant polyphenolic constituents and reference antioxidants. All studied ethanolic extracts exhibited considerable activity to scavenge DPPH and hydroxyl free radicals, reducing power, iron chelating ability and total antioxidant capacity in the order: M. croatica > M. juliana > M. thymifolia. Total polyphenol (9.69–13.66%), phenolic acid (5.26–6.84%), flavonoid (0.01–0.09%) and tannin (3.07–6.48%) contents in dried plant samples were determined spectrophotometrically. A strong positive correlation between antioxidant activities and contents of phenolic acids and tannins was found, indicating their responsibility for effectiveness of tested plants. Our findings established Micromeria species as a rich source of antioxidant polyphenols, especially the endemic M. croatica. Full article
(This article belongs to the Section Natural Products Chemistry)
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225 KiB  
Article
Polycationic Glycosides
by Robert Engel, Ishrat Ghani, Diego Montenegro, Marie Thomas, Barbara Klaritch-Vrana, Alejandra Castaño, Laura Friedman, Jay Leb, Leah Rothman, Heidi Lee, Craig Capodiferro, Daniel Ambinder, Eva Cere, Christopher Awad, Faiza Sheikh, JaimeLee Rizzo, Lisa-Marie Nisbett, Erika Testani and Karin Melkonian
Molecules 2011, 16(2), 1508-1518; https://doi.org/10.3390/molecules16021508 - 11 Feb 2011
Cited by 21 | Viewed by 9184
Abstract
Cationic lipids have long been known to serve as antibacterial and antifungal agents. Prior efforts with attachment of cationic lipids to carbohydrate-based surfaces have suggested the possibility that carbohydrate-attached cationic lipids might serve as antibacterial and antifungal pharmaceutical agents. Toward the understanding of [...] Read more.
Cationic lipids have long been known to serve as antibacterial and antifungal agents. Prior efforts with attachment of cationic lipids to carbohydrate-based surfaces have suggested the possibility that carbohydrate-attached cationic lipids might serve as antibacterial and antifungal pharmaceutical agents. Toward the understanding of this possibility, we have synthesized several series of cationic lipids attached to a variety of glycosides with the intent of generating antimicrobial agents that would meet the requirement for serving as a pharmaceutical agent, specifically that the agent be effective at a very low concentration as well as being biodegradable within the organism being treated. The initial results of our approach to this goal are presented. Full article
(This article belongs to the Special Issue Glycosides)
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292 KiB  
Article
Tannin Composition of Cabernet-Sauvignon and Merlot Grapes from the Bordeaux Area for Different Vintages (2006 to 2009) and Comparison to Tannin Profile of Five 2009 Vintage Mediterranean Grapes Varieties
by Kleopatra Chira, Bénédicte Lorrain, Isabelle Ky and Pierre-Louis Teissedre
Molecules 2011, 16(2), 1519-1532; https://doi.org/10.3390/molecules16021519 - 11 Feb 2011
Cited by 41 | Viewed by 9606
Abstract
The proanthocyandin composition of skins and seeds of Bordeaux Merlot (M) and Cabernet Sauvignon (CS) grapes was evaluated by HPLC-UV-fluorescence for four consecutive vintages (2006 to 2009). The results indicated a strong vintage effect on the tannin profile of each variety. However, and [...] Read more.
The proanthocyandin composition of skins and seeds of Bordeaux Merlot (M) and Cabernet Sauvignon (CS) grapes was evaluated by HPLC-UV-fluorescence for four consecutive vintages (2006 to 2009). The results indicated a strong vintage effect on the tannin profile of each variety. However, and in spite of the vintage effect, some tannin characteristics such as mDP, %G and %P allow discrimination of both Bordeaux varieties. The same analyses were carried out for the 2009 vintage of five Mediterranean grape varieties (Syrah, Grenache, Mourvedre, Carignan and Counoise). The results demonstrated differences among these five varieties. Syrah appeared to exhibit the highest concentrations of flavanol monomers and dimmers, especially in skins. The comparison study between Bordeaux and Mediterranean grape varieties for the same vintage (2009) revealed that mDP and %G for seed extracts were parameters specific to each vineyard area. Full article
(This article belongs to the Special Issue Tannins)
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225 KiB  
Article
Fast and Sensitive LC-DAD-ESI/MS Method for Analysis of Saikosaponins c, a, and d from the Roots of Bupleurum Falcatum (Sandaochaihu)
by Li-Chun Zhao, Wei Li, Yu-Fang He, Xiao-Hua Li, Zi Wang, Wen-Cong Liu, Yi-Nan Zheng and Jian Liang
Molecules 2011, 16(2), 1533-1543; https://doi.org/10.3390/molecules16021533 - 11 Feb 2011
Cited by 6 | Viewed by 12990
Abstract
In the present study, we developed a liquid chromatography-diode array detector-electrospray ionization/mass spectrometric (LC-DAD-ESI/MS) method for analysis of saikosaponins in Bupleurum falcatum. The LC method employed a ZORBAX SB-Aq analytical column (150 × 4.6 mm i.d., 5 μm) at a flow rate [...] Read more.
In the present study, we developed a liquid chromatography-diode array detector-electrospray ionization/mass spectrometric (LC-DAD-ESI/MS) method for analysis of saikosaponins in Bupleurum falcatum. The LC method employed a ZORBAX SB-Aq analytical column (150 × 4.6 mm i.d., 5 μm) at a flow rate of 0.8 mL/min coupled with a diode array detector at 204 nm. A step gradient of acetonitrile-water (v/v) containing 0.5% formic acid from 30 to 70% was applied, leading to a sample analysis time of 30 min. The ESI-MS was carried out in positive and negative modes from 500 to 1,500 m/z. Saikosaponins c, a, and d gave strong sodium adducts at m/z 949.6, 803.5 and 803.6, respectively, in positive mode. The data indicate that the present LC-DAD-ESI/MS assay is an effective method for the determination of saikosaponins c, a and d from the roots of Bupleurum falcatum. Full article
(This article belongs to the Collection Bioactive Compounds)
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1311 KiB  
Article
Identification and Characterization of Three Novel Small Interference RNAs That Effectively Down-Regulate the Isolated Nucleocapsid Gene Expression of SARS Coronavirus
by Ying-Li Cao, Ying Wang, Rong Guo, Fan Yang, Yun Zhang, Shu-Hui Wang and Li Liu
Molecules 2011, 16(2), 1544-1558; https://doi.org/10.3390/molecules16021544 - 11 Feb 2011
Cited by 5 | Viewed by 9793
Abstract
Nucleocapsid (N) protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is a major pathological determinant in the host that may cause host cell apoptosis, upregulate the proinflammatory cytokine production, and block innate immune responses. Therefore, N gene has long been thought an ideal [...] Read more.
Nucleocapsid (N) protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is a major pathological determinant in the host that may cause host cell apoptosis, upregulate the proinflammatory cytokine production, and block innate immune responses. Therefore, N gene has long been thought an ideal target for the design of small interference RNA (siRNA). siRNA is a class of small non-coding RNAs with a size of 21-25nt that functions post-transcriptionally to block targeted gene expression. In this study, we analyzed the N gene coding sequences derived from 16 different isolates, and found that nucleotide deletions and substitutions are mainly located at the first 440nt sequence. Combining previous reports and the above sequence information, we create three novel siRNAs that specifically target the conserved and unexploited regions in the N gene. We show that these siRNAs could effectively and specifically block the isolated N gene expression in mammal cells. Furthermore, we provide evidence to show that N gene can effectively up-regulate M gene mediated interferon b (IFNb) production, while blocking N gene expression by specific siRNA significantly reduces IFNb gene expression. Our data indicate that the inhibitory effect of siRNA on the isolated N gene expression might be influenced by the sequence context around the targeted sites. Full article
(This article belongs to the Special Issue Antivirals)
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475 KiB  
Article
Challenges in Optimizing a Prostate Carcinoma Binding Peptide, Identified through the Phage Display Technology
by Vasileios Askoxylakis, Sabine Zitzmann-Kolbe, Frederic Zoller, Annette Altmann, Annette Markert, Shoaib Rana, Annabell Marr, Walter Mier, Jürgen Debus and Uwe Haberkorn
Molecules 2011, 16(2), 1559-1578; https://doi.org/10.3390/molecules16021559 - 14 Feb 2011
Cited by 16 | Viewed by 7949
Abstract
The transfer of peptides identified through the phage display technology to clinical applications is difficult. Major drawbacks are the metabolic degradation and label instability. The aim of our work is the optimization of DUP-1, a peptide which was identified by phage display to [...] Read more.
The transfer of peptides identified through the phage display technology to clinical applications is difficult. Major drawbacks are the metabolic degradation and label instability. The aim of our work is the optimization of DUP-1, a peptide which was identified by phage display to specifically target human prostate carcinoma. To investigate the influence of chelate conjugation, DOTA was coupled to DUP-1 and labeling was performed with 111In. To improve serum stability cyclization of DUP-1 and targeted D-amino acid substitution were carried out. Alanine scanning was performed for identification of the binding site and based on the results peptide fragments were chemically synthesized. The properties of modified ligands were investigated in in vitro binding and competition assays. In vivo biodistribution studies were carried out in mice, carrying human prostate tumors subcutaneously. DOTA conjugation resulted in different cellular binding kinetics, rapid in vivo renal clearance and increased tumor-to-organ ratios. Cyclization and D-amino acid substitution increased the metabolic stability but led to binding affinity decrease. Fragment investigation indicated that the sequence NRAQDY might be significant for target-binding. Our results demonstrate challenges in optimizing peptides, identified through phage display libraries, and show that careful investigation of modified derivatives is necessary in order to improve their characteristics. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
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277 KiB  
Article
In Vitro and In Vivo Antioxidant Activity of a Water-Soluble Polysaccharide from Dendrobium denneanum
by Aoxue Luo, Zhongfu Ge, Yijun Fan, Aoshuang Luo, Ze Chun and XingJin He
Molecules 2011, 16(2), 1579-1592; https://doi.org/10.3390/molecules16021579 - 14 Feb 2011
Cited by 61 | Viewed by 7750
Abstract
The water-soluble crude polysaccharide (DDP) obtained from the aqueous extracts of the stem of Dendrobium denneanum through hot water extraction followed by ethanol precipitation, was found to have an average molecular weight (Mw) of about 484.7 kDa. Monosaccharide analysis revealed that DDP [...] Read more.
The water-soluble crude polysaccharide (DDP) obtained from the aqueous extracts of the stem of Dendrobium denneanum through hot water extraction followed by ethanol precipitation, was found to have an average molecular weight (Mw) of about 484.7 kDa. Monosaccharide analysis revealed that DDP was composed of arabinose, xylose, mannose, glucose and galactose in a molar ratio of 1.00:2.66:8.92:34.20:10.16. The investigation of antioxidant activity both in vitro and in vivo showed that DDP is a potential antioxidant. Full article
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218 KiB  
Article
Synthesis and Anti-Intestinal Nematode Activity of Variously Substituted Benzonaphthyridine Derivatives
by Li-Ping Duan, Ai-Dan Wen, Ning-Bo Wu, Yi Tao and Hao-Bing Zhang
Molecules 2011, 16(2), 1593-1602; https://doi.org/10.3390/molecules16021593 - 14 Feb 2011
Cited by 9 | Viewed by 6725
Abstract
A series of benzonaphthyridine derivatives bearing the C=N linkage moiety were designed and synthesized. The structures of all the newly synthesized compounds were identified by elemental analysis, 1H-NMR, 13C-NMR and MS. Their anti-intestinal nematode activities against Nippostrongylus brazilliensis were evaluated in [...] Read more.
A series of benzonaphthyridine derivatives bearing the C=N linkage moiety were designed and synthesized. The structures of all the newly synthesized compounds were identified by elemental analysis, 1H-NMR, 13C-NMR and MS. Their anti-intestinal nematode activities against Nippostrongylus brazilliensis were evaluated in vivo by an oral route in male rats. Among these compounds, at concentrations of 10 mg/kg of rat, the compound 7-chloro-2-methoxy-10-(4-(4′-(1H-indol-5′-yl)methylene)aminophenyl)-amino-benzo[b][1,5] naphthyridine (4n) produced the highest activity, with 80.2% deparasitization. These compounds may find usefulness in the discovery and development of new anti-intestinal drugs. Full article
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471 KiB  
Article
Peppermint Oil Decreases the Production of Virulence-Associated Exoproteins by Staphylococcus aureus
by Jing Li, Jing Dong, Jia-Zhang Qiu, Jian-Feng Wang, Ming-Jing Luo, Hong-En Li, Bing-Feng Leng, Wen-Zhi Ren and Xu-Ming Deng
Molecules 2011, 16(2), 1642-1654; https://doi.org/10.3390/molecules16021642 - 15 Feb 2011
Cited by 33 | Viewed by 10085
Abstract
The present study aimed to evaluate the antimicrobial activity of peppermint oil against Staphylococcus aureus, and further investigate the influence of peppermint oil on S. aureus virulence-related exoprotein production. The data show that peppermint oil, which contained high contents of menthone, isomenthone, [...] Read more.
The present study aimed to evaluate the antimicrobial activity of peppermint oil against Staphylococcus aureus, and further investigate the influence of peppermint oil on S. aureus virulence-related exoprotein production. The data show that peppermint oil, which contained high contents of menthone, isomenthone, neomenthol, menthol, and menthyl acetate, was active against S. aureus with minimal inhibitory concentrations (MICs) ranging from 64-256 µg/mL, and the production of S. aureus exotoxins was decreased by subinhibitory concentrations of peppermint oil in a dose-dependent manner. The findings suggest that peppermint oil may potentially be used to aid in the treatment of S. aureus infections. Full article
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552 KiB  
Article
The Influence of Comonomer on Ethylene/α-Olefin Copolymers Prepared Using [Bis(N-(3-tert butylsalicylidene)anilinato)] Titanium (IV) Dichloride Complex
by Patcharaporn Kaivalchatchawal, Pattiya Suttipitakwong, Sutheerawat Samingprai, Piyasan Praserthdam and Bunjerd Jongsomjit
Molecules 2011, 16(2), 1655-1666; https://doi.org/10.3390/molecules16021655 - 15 Feb 2011
Cited by 9 | Viewed by 7131
Abstract
We describe the synthesis of [bis(N-(3-tert-butylsalicylidene)anilinato)] titanium (IV) dichloride (Ti-FI complex) and examine the effects of comonomer (feed concentration and type) on its catalytic performance and properties of the resulting polymers. Ethylene/1-hexene and ethylene/1-octene copolymers were prepared through copolymerization [...] Read more.
We describe the synthesis of [bis(N-(3-tert-butylsalicylidene)anilinato)] titanium (IV) dichloride (Ti-FI complex) and examine the effects of comonomer (feed concentration and type) on its catalytic performance and properties of the resulting polymers. Ethylene/1-hexene and ethylene/1-octene copolymers were prepared through copolymerization using Ti-FI catalyst, activated by MAO cocatalyst at 323 K and 50 psi ethylene pressure at various initial comonomer concentrations. The obtained copolymers were characterized by DSC, GPC and 13C-NMR. The results indicate that Ti-FI complex performs as a high potential catalyst, as evidenced by high activity and high molecular weight and uniform molecular weight distribution of its products. Nevertheless, the bulky structure of FI catalyst seems to hinder the insertion of α-olefin comonomer, contributing to the pretty low comonomer incorporation into the polymer chain. The catalytic activity was enhanced with the comonomer feed concentration, but the molecular weight and melting temperature decreased. By comparison both sets of catalytic systems, namely ethylene/1-hexene and ethylene/1-octene copolymerization, the first one afforded better activity by reason of easier insertion of short chain comonomer. Although 1-hexene copolymers also exhibited higher molecular weight than 1-octene, no significant difference in both melting temperature and crystallinity can be noticed between these comonomers. Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
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278 KiB  
Article
Bis-Indole Derivatives for Polysaccharide Compositional Analysis and Chiral Resolution of D-, L-Monosaccharides by Ligand Exchange Capillary Electrophoresis Using Borate-Cyclodextrin as a Chiral Selector
by Chien-Yuan Kuo, Kuo-Shiang Liao, Yin-Chen Liu and Wen-Bin Yang
Molecules 2011, 16(2), 1682-1694; https://doi.org/10.3390/molecules16021682 - 17 Feb 2011
Cited by 19 | Viewed by 8478
Abstract
A series of aldo-bis-indole derivatives (aldo-BINs) was prepared by aromatic C-alkylation reactions of aldoses and indole in acetic acid solution. Common monosaccharides such as glucose, mannose, galactose, fucose, xylose, rhamnose, ribose, arabinose and N-acetylglucosamine were smoothly derivatized to form the UV [...] Read more.
A series of aldo-bis-indole derivatives (aldo-BINs) was prepared by aromatic C-alkylation reactions of aldoses and indole in acetic acid solution. Common monosaccharides such as glucose, mannose, galactose, fucose, xylose, rhamnose, ribose, arabinose and N-acetylglucosamine were smoothly derivatized to form the UV absorbing aldo-BINs. The use of a capillary electrophoretic method to separate these novel aldo-BIN derivatives was established. The capillary electrophoresis conditions were set by using borate buffer (100 mM) at high pH (pH 9.0). The limit of determination was assessed to be 25 nM. The enantioseparation of D, L-pairs of aldo-BINs based on chiral ligand-exchange capillary electrophoresis technology was also achieved by using modified hydroxypropyl-β-cyclodextrin as the chiral selector in the presence of borate buffer. This aldose labeling method was applied successfully to the compositional and configurational analysis of saccharides, exemplified by a rapid and efficient method to simultaneously analyze the composition and configuration of saccharides from the medicinal herbs Cordyceps sinensis and Dendrobium huoshanense. Full article
(This article belongs to the Special Issue Glycosides)
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147 KiB  
Article
Eucalyptus oleosa Essential Oils: Chemical Composition and Antimicrobial and Antioxidant Activities of the Oils from Different Plant Parts (Stems, Leaves, Flowers and Fruits)
by Hajer Naceur Ben Marzoug, Mehrez Romdhane, Ahmed Lebrihi, Florence Mathieu, François Couderc, Manef Abderraba, Mohamed Larbi Khouja and Jalloul Bouajila
Molecules 2011, 16(2), 1695-1709; https://doi.org/10.3390/molecules16021695 - 17 Feb 2011
Cited by 139 | Viewed by 16359
Abstract
Essential oils obtained by hydrodistillation from the different parts (stems, adult leaves, immature flowers and fruits) of Eucalyptus oleosa were screened for their antioxidant and antimicrobial properties and their chemical composition. According to GC-FID and GC-MS, the principal compound of the stem, immature [...] Read more.
Essential oils obtained by hydrodistillation from the different parts (stems, adult leaves, immature flowers and fruits) of Eucalyptus oleosa were screened for their antioxidant and antimicrobial properties and their chemical composition. According to GC-FID and GC-MS, the principal compound of the stem, immature flowers and the fruit oils was 1,8-cineole, representing 31.5%, 47.0% and 29.1%, respectively. Spathulenol (16.1%) and γ-eudesmol (15.0%) were the two principal compounds of adult leaves oil. In the DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, the oils of the four parts showed moderate antioxidant activity. In the ABTS (2,2’-azinobis-3-ethylbenzothiazoline-6-sulphonate) assay, the most active part was the adult leaves, with a IC50 value 13.0 ± 0.6 mg/L, followed by stems (IC50 = 43.5 ± 1.4 mg/L). The essential oils showed a better antibacterial activity against Gram-positive and Gram-negative bacteria, and a significant antifungal activity also was observed against yeast-like fungi. A strong correlations between oxygenated monoterpenes and antimicrobial activity (especially 1,8-cineole) were noted (R2 = 0.99, 0.97 and 0.79 for B. subtilis, P. aeruginosa and C. albicans, respectively). Full article
(This article belongs to the Collection Bioactive Compounds)
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223 KiB  
Article
Identification of Calpain Substrates by ORF Phage Display
by Nora B. Caberoy, Gabriela Alvarado and Wei Li
Molecules 2011, 16(2), 1739-1748; https://doi.org/10.3390/molecules16021739 - 21 Feb 2011
Cited by 10 | Viewed by 7533
Abstract
Substrate identification is the key to defining molecular pathways or cellular processes regulated by proteases. Although phage display with random peptide libraries has been used to analyze substrate specificity of proteases, it is difficult to deduce endogenous substrates from mapped peptide motifs. Phage [...] Read more.
Substrate identification is the key to defining molecular pathways or cellular processes regulated by proteases. Although phage display with random peptide libraries has been used to analyze substrate specificity of proteases, it is difficult to deduce endogenous substrates from mapped peptide motifs. Phage display with conventional cDNA libraries identifies high percentage of non-open reading frame (non-ORF) clones, which encode short unnatural peptides, owing to uncontrollable reading frames of cellular proteins. We recently developed ORF phage display to identify endogenous proteins with specific binding or functional activity with minimal reading frame problem. Here we used calpain 2 as a protease to demonstrate that ORF phage display is capable of identifying endogenous substrates and showed its advantage to re-verify and characterize the identified substrates without requiring pure substrate proteins. An ORF phage display cDNA library with C-terminal biotin was bound to immobilized streptavidin and released by cleavage with calpain 2. After three rounds of phage selection, eleven substrates were identified, including calpastatin of endogenous calpain inhibitor. These results suggest that ORF phage display is a valuable technology to identify endogenous substrates for proteases. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
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326 KiB  
Article
Structure of Dihydrochalcones and Related Derivatives and Their Scavenging and Antioxidant Activity against Oxygen and Nitrogen Radical Species
by Alexandre L. A. Bentes, Rosivaldo S. Borges, Waldinei R. Monteiro, Luiz G. M. De Macedo and Cláudio N. Alves
Molecules 2011, 16(2), 1749-1760; https://doi.org/10.3390/molecules16021749 - 21 Feb 2011
Cited by 52 | Viewed by 11596
Abstract
Quantum mechanical calculations at B3LYP/6-31G** level of theory were employed to obtain energy (E), ionization potential (IP), bond dissociation enthalpy (O-H BDE) and stabilization energies (DEiso) in order to infer the scavenging activity of dihydrochalcones (DHC) and structurally related compounds. Spin [...] Read more.
Quantum mechanical calculations at B3LYP/6-31G** level of theory were employed to obtain energy (E), ionization potential (IP), bond dissociation enthalpy (O-H BDE) and stabilization energies (DEiso) in order to infer the scavenging activity of dihydrochalcones (DHC) and structurally related compounds. Spin density calculations were also performed for the proposed antioxidant activity mechanism of 2,4,6-trihydroxyacetophenone (2,4,6-THA). The unpaired electron formed by the hydrogen abstraction from the phenolic hydroxyl group of 2,4,6-THA is localized on the phenolic oxygen at 2, 6, and 4 positions, the C3 and C6 carbon atoms at ortho positions, and the C5 carbon atom at para position. The lowest phenolic oxygen contribution corresponded to the highest scavenging activity value. It was found that antioxidant activity depends on the presence of a hydroxyl at the C2 and C4 positions and that there is a correlation between IP and O-H BDE and peroxynitrite scavenging activity and lipid peroxidation. These results identified the pharmacophore group for DHC. Full article
(This article belongs to the Special Issue Antioxidants)
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2741 KiB  
Article
Effects of Bentonite on p-Methoxybenzyl Acetate: A Theoretical Model for Oligomerization via an Electrophilic-Substitution Mechanism
by Manuel Salmón, Rene Miranda, Ines Nicolás-Vázquez, Yolanda Marina Vargas-Rodriguez, Julian Cruz-Borbolla, María Isabel Medrano and José Antonio Morales-Serna
Molecules 2011, 16(2), 1761-1775; https://doi.org/10.3390/molecules16021761 - 21 Feb 2011
Cited by 8 | Viewed by 10533
Abstract
Tonsil Actisil FF, a commercial bentonitic clay, promotes the formation of a series of electrophilic-aromatic-substitution products from para-methoxybenzyl acetate in carbon disulfide. The molecules obtained correspond to linear isomeric dimers, trimers, tetramers and a pentamer, according to their spectroscopic data. A clear [...] Read more.
Tonsil Actisil FF, a commercial bentonitic clay, promotes the formation of a series of electrophilic-aromatic-substitution products from para-methoxybenzyl acetate in carbon disulfide. The molecules obtained correspond to linear isomeric dimers, trimers, tetramers and a pentamer, according to their spectroscopic data. A clear indication of the title mechanistic pathway for the oligomerization growth was obtained from the analysis of a set of computational-chemistry calculations using the density-functional-theory level B3LYP/6-311++G(d,p). The corresponding conclusions were based on the computed dipole moments, the HOMO/LUMO distributions, and a natural-populations analysis of the studied molecules. Full article
(This article belongs to the Section Organic Chemistry)
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336 KiB  
Article
New Chiral P-N Ligands for the Regio- and Stereoselective Pd-Catalyzed Dimerization of Styrene
by Lidia Fanfoni, Angelo Meduri, Ennio Zangrando, Sergio Castillon, Fulvia Felluga and Barbara Milani
Molecules 2011, 16(2), 1804-1824; https://doi.org/10.3390/molecules16021804 - 22 Feb 2011
Cited by 16 | Viewed by 11202
Abstract
Two new chiral, enantiomerically pure, hybrid P-N ligands, namely (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octan-4-one (1) and (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octane (2), have been synthesized starting from L-proline. The two ligands differ in the presence or not of a [...] Read more.
Two new chiral, enantiomerically pure, hybrid P-N ligands, namely (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octan-4-one (1) and (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octane (2), have been synthesized starting from L-proline. The two ligands differ in the presence or not of a carbonyl group in the diazaphosphane ring. Their coordination chemistry towards Pd(II) was studied by reacting them with [Pd(CH3)Cl(cod)]. A different behaviour was observed: ligand 2 shows the expected bidentate chelating behaviour leading to the mononuclear Pd-complex, while ligand 1 acts as a terdentate ligand giving a dinuclear species. The corresponding cationic derivatives were obtained from the palladium neutral complexes, both as mono- and dinuclear derivatives, and tested as precatalysts for styrene dimerization, yielding E-1,3-diphenyl-1-butene regio- and stereoselectively as the sole product. A detailed analysis of the catalytic behaviour is reported. Full article
(This article belongs to the Special Issue Homogeneous Catalysis)
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123 KiB  
Article
Antileishmanial Activity of the Hydroalcoholic Extract of Miconia langsdorffii, Isolated Compounds, and Semi-Synthetic Derivatives
by Juliana A. Peixoto, Márcio Luis Andrade e Silva, Antônio E. M. Crotti, Rodrigo Cassio Sola Veneziani, Valéria M. M. Gimenez, Ana H. Januário, Milton Groppo, Lizandra G. Magalhães, Fransérgio F. Dos Santos, Sérgio Albuquerque, Ademar A. Da Silva Filho and Wilson R. Cunha
Molecules 2011, 16(2), 1825-1833; https://doi.org/10.3390/molecules16021825 - 22 Feb 2011
Cited by 43 | Viewed by 10010
Abstract
The in vitro activity of the crude hydroalcoholic extract of the aerial parts of Miconia langsdorffii Cogn. was evaluated against the promastigote forms of L. amazonensis, the causative agent of cutaneous leishmaniasis in humans. The bioassay-guided fractionation of this extract led to [...] Read more.
The in vitro activity of the crude hydroalcoholic extract of the aerial parts of Miconia langsdorffii Cogn. was evaluated against the promastigote forms of L. amazonensis, the causative agent of cutaneous leishmaniasis in humans. The bioassay-guided fractionation of this extract led to identification of the triterpenes ursolic acid and oleanolic acid as the major compounds in the fraction that displayed the highest activity. Several ursolic acid semi-synthetic derivatives were prepared, to find out whether more active compounds could be obtained. Among these ursolic acid-derived substances, the C-28 methyl ester derivative exhibited the best antileishmanial activity. Full article
(This article belongs to the Section Natural Products Chemistry)
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396 KiB  
Article
Enaminones as Building Blocks for the Synthesis of Substituted Pyrazoles with Antitumor and Antimicrobial Activities
by Sayed M. Riyadh
Molecules 2011, 16(2), 1834-1853; https://doi.org/10.3390/molecules16021834 - 22 Feb 2011
Cited by 65 | Viewed by 8188
Abstract
Novel N-arylpyrazole-containing enaminones 2a,b were synthesized as key intermediates. Reactions of 2a,b with active methylene compounds in acetic acid in the presence of ammonium acetate afforded substituted pyridine derivatives 5a-d. Enaminones 2a,b also reacted with aliphatic amines such as hydrazine hydrate [...] Read more.
Novel N-arylpyrazole-containing enaminones 2a,b were synthesized as key intermediates. Reactions of 2a,b with active methylene compounds in acetic acid in the presence of ammonium acetate afforded substituted pyridine derivatives 5a-d. Enaminones 2a,b also reacted with aliphatic amines such as hydrazine hydrate and hydroxylamine hydrochloride to give bipyrazoles 8a,b and pyrazolylisoxazoles 9a,b, respectively. On the other hand, treatment of 2a,b with a heterocyclic amine and its diazonium salt yielded the respective [1,2,4]triazolo[4,3-a]pyrimidines 12a,b and pyrazolylcarbonyl[1,2,4]triazolo-[3,4-c][1,2,4]triazines 14a,b. Moreover, 2-thioxo-2,3-dihydro-1H-pyrido[2,3-d]pyrimidin-4-one (17) was prepared via reaction of enaminone 2a with aminothiouracil (15). Cyclocondensation of 17 with the appropriate hydrazonoyl chlorides 18a-c gave the corresponding pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones 21a-c. The cytotoxic effects of compounds 2b, 14a and 17 against human breast cell line (MCF-7) and liver carcinoma cell line (HEPG2) were screened and in both lines they showed inhibition effects comparable to those of 5-fluorouracil, used as a standard. The antimicrobial activity of some products chosen as representative examples was also evaluated. Full article
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157 KiB  
Article
Tin (IV) Chloride-Promoted One-Pot Synthesis of Novel Tacrine Analogues
by Huanan Hu, Liangfu Song, Qianqian Fang, Junjun Zheng, Zhiwei Meng and Yiting Luo
Molecules 2011, 16(2), 1878-1887; https://doi.org/10.3390/molecules16021878 - 22 Feb 2011
Cited by 13 | Viewed by 6098
Abstract
A facile synthesis of potential acetylcholinesterase (AChE) inhibitors, the tacrine analogues 3a-p, has been accomplished by direct cyclocondensation of 1-aryl-4-cyano-5-aminopyrazole with β-ketoesters using tin(IV) chloride as catalyst. The structures of all the compounds have been confirmed by IR, 1H- and 13C-NMR. Full article
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197 KiB  
Article
Synthesis, Characterization and Biological Evaluation of Succinate Prodrugs of Curcuminoids for Colon Cancer Treatment
by Wisut Wichitnithad, Ubonthip Nimmannit, Sumrit Wacharasindhu and Pornchai Rojsitthisak
Molecules 2011, 16(2), 1888-1900; https://doi.org/10.3390/molecules16021888 - 22 Feb 2011
Cited by 101 | Viewed by 12809
Abstract
A novel series of succinyl derivatives of three curcuminoids were synthesized as potential prodrugs. Symmetrical (curcumin and bisdesmethoxycurcumin) and unsymmetrical (desmethoxycurcumin) curcuminoids were prepared through aldol condensation of 2,4-pentanedione with different benzaldehydes. Esterification of these compounds with a methyl or ethyl ester of [...] Read more.
A novel series of succinyl derivatives of three curcuminoids were synthesized as potential prodrugs. Symmetrical (curcumin and bisdesmethoxycurcumin) and unsymmetrical (desmethoxycurcumin) curcuminoids were prepared through aldol condensation of 2,4-pentanedione with different benzaldehydes. Esterification of these compounds with a methyl or ethyl ester of succinyl chloride gave the corresponding succinate prodrugs in excellent yields. Anticolon cancer activity of the compounds was evaluated using Caco-2 cells. The succinate prodrugs had IC50 values in the 1.8–9.6 μM range, compared to IC50 values of 3.3–4.9 μM for the parent compounds. Curcumin diethyl disuccinate exhibited the highest potency and was chosen for stability studies. Hydrolysis of this compound in phosphate buffer at pH 7.4 and in human plasma followed pseudo first-order kinetics. In phosphate buffer, the kobs and t1/2 for hydrolysis indicated that the compound was much more stable than curcumin. In human plasma, this compound was able to release curcumin, therefore our results suggest that succinate prodrugs of curcuminoids are stable in phosphate buffer, release the parent curcumin derivatives readily in human plasma, and show anti-colon cancer activity. Full article
(This article belongs to the Special Issue Prodrugs)
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192 KiB  
Article
Three New Steroidal Glycosides from the Roots of Cynanchum auriculatum
by Yu Lu, Hong-Li Teng, Guang-Zhong Yang and Zhi-Nan Mei
Molecules 2011, 16(2), 1901-1909; https://doi.org/10.3390/molecules16021901 - 23 Feb 2011
Cited by 16 | Viewed by 8390
Abstract
Three new steroidal glycosides, cyanoauriculosides F, G and H (1-3), were isolated from the roots of Cynanchum auriculatum (Asclepiadaceae) along with two known steroidal derivatives. On the basis of spectroscopic analysis and chemical methods, their structures were identified as [...] Read more.
Three new steroidal glycosides, cyanoauriculosides F, G and H (1-3), were isolated from the roots of Cynanchum auriculatum (Asclepiadaceae) along with two known steroidal derivatives. On the basis of spectroscopic analysis and chemical methods, their structures were identified as 20-O-acetyl-8,14-seco-penupogenin-8-one 3-O-α-L-cymaropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-α-L-diginopyranosyl-(1→4)-β-D-cymaropyranoside (1), 2′,3′-Z-gagaminine 3-O-α-L-cymaropyranosyl-(1→4)-β-D-cymaro-pyranosyl-(1→4)-α-L-diginopyranosyl-(1→4)-β-D-cymaropyranoside (2), 17-O-acetyl-kidjoranin 3-O-α-L-cymaropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-α-L-cymaro-pyranosyl-(1→4)-β-D-digitoxopyranosyl-(1→4)-β-D-digitoxopyranoside (3), gagaminine 3-O-α-L-cymaropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-α-L-digino-pyranosyl-(1→4)-β-D-cymaropyranoside (4) and wilfoside D1N (5). Full article
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231 KiB  
Article
Dihydroberkleasmin A: A New Eremophilane Sesquiterpenoid from the Fermentation Broth of the Plant Endophytic Fungus Pestalotiopsis photiniae
by Xiao-Long Yang, Su Zhang, Hua-Jie Zhu and Du-Qiang Luo
Molecules 2011, 16(2), 1910-1916; https://doi.org/10.3390/molecules16021910 - 23 Feb 2011
Cited by 18 | Viewed by 6663
Abstract
Dihydroberkleasmin A (1), a new ester-substituted sesquiterpenoid related to the eremophilane class, together with the known compound berkleasmin C (2), were isolated from the fermentation broth of the plant endophytic fungus Pestalotiopsis photiniae. The structure of dihydroberkleasmin A [...] Read more.
Dihydroberkleasmin A (1), a new ester-substituted sesquiterpenoid related to the eremophilane class, together with the known compound berkleasmin C (2), were isolated from the fermentation broth of the plant endophytic fungus Pestalotiopsis photiniae. The structure of dihydroberkleasmin A (1) was elucidated by extensive spectroscopic analysis. The stereochemistry was assigned by comparison of the NMR spectroscopic data with those of berkleasmin A. Full article
(This article belongs to the Collection Bioactive Compounds)
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Review

Jump to: Editorial, Research

1008 KiB  
Review
Inhibitors of Microglial Neurotoxicity: Focus on Natural Products
by Dong Kug Choi, Sushruta Koppula and Kyoungho Suk
Molecules 2011, 16(2), 1021-1043; https://doi.org/10.3390/molecules16021021 - 25 Jan 2011
Cited by 115 | Viewed by 19831
Abstract
Microglial cells play a dual role in the central nervous system as they have both neurotoxic and neuroprotective effects. Uncontrolled and excessive activation of microglia often contributes to inflammation-mediated neurodegeneration. Recently, much attention has been paid to therapeutic strategies aimed at inhibiting neurotoxic [...] Read more.
Microglial cells play a dual role in the central nervous system as they have both neurotoxic and neuroprotective effects. Uncontrolled and excessive activation of microglia often contributes to inflammation-mediated neurodegeneration. Recently, much attention has been paid to therapeutic strategies aimed at inhibiting neurotoxic microglial activation. Pharmacological inhibitors of microglial activation are emerging as a result of such endeavors. In this review, natural products-based inhibitors of microglial activation will be reviewed. Potential neuroprotective activity of these compounds will also be discussed. Future works should focus on the discovery of novel drug targets that specifically mediate microglial neurotoxicity rather than neuroprotection. Development of new drugs based on these targets may require a better understanding of microglial biology and neuroinflammation at the molecular, cellular, and systems levels. Full article
(This article belongs to the Section Natural Products Chemistry)
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361 KiB  
Review
Compilation of Secondary Metabolites from Bidens pilosa L.
by Fabiana Lima Silva, Dominique Corinne Hermine Fischer, Josean Fechine Tavares, Marcelo Sobral Silva, Petronio Filgueiras de Athayde-Filho and Jose Maria Barbosa-Filho
Molecules 2011, 16(2), 1070-1102; https://doi.org/10.3390/molecules16021070 - 26 Jan 2011
Cited by 105 | Viewed by 21922
Abstract
Bidens pilosa L. is a cosmopolitan annual herb, known for its traditional use in treating various diseases and thus much studied for the biological activity of its extracts, fractions and isolated compounds. Polyacetylenes and flavonoids, typical metabolite classes in the Bidens genus, predominate [...] Read more.
Bidens pilosa L. is a cosmopolitan annual herb, known for its traditional use in treating various diseases and thus much studied for the biological activity of its extracts, fractions and isolated compounds. Polyacetylenes and flavonoids, typical metabolite classes in the Bidens genus, predominate in the phytochemistry of B. pilosa. These classes of compounds have great taxonomic significance. In the Asteraceae family, the acetylene moiety is widely distributed in the Heliantheae tribe and some representatives, such as 1-phenylhepta-1,3,5-triyne, are noted for their biological activity and strong long-wave UV radiation absorbance. The flavonoids, specifically aurones and chalcones, have been reported as good sub-tribal level markers. Natural products from several other classes have also been isolated from different parts of B. pilosa. This review summarizes the available information on the 198 natural products isolated to date from B. pilosa. Full article
(This article belongs to the Section Natural Products Chemistry)
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949 KiB  
Review
Cross-Coupling Reactions as Valuable Tool for the Preparation of PET Radiotracers
by Marc Pretze, Philipp Große-Gehling and Constantin Mamat
Molecules 2011, 16(2), 1129-1165; https://doi.org/10.3390/molecules16021129 - 26 Jan 2011
Cited by 44 | Viewed by 13357
Abstract
The increasing application of positron emission tomography (PET) in nuclear medicine has stimulated the extensive development of a multitude of new radiotracers and novel radiolabeling procedures with the most prominent short-lived positron emitters carbon-11 and fluorine-18. Radiolabeling with these radionuclides represents a remarkable [...] Read more.
The increasing application of positron emission tomography (PET) in nuclear medicine has stimulated the extensive development of a multitude of new radiotracers and novel radiolabeling procedures with the most prominent short-lived positron emitters carbon-11 and fluorine-18. Radiolabeling with these radionuclides represents a remarkable challenge. Special attention has to be paid to synthesis time and specific labeling techniques due to the short physical half life of the respective radionuclides 11C (t1/2 = 20.4 min) and 18F (t1/2 = 109.8 min). In the past, numerous transition metal-catalyzed reactions were employed in organic chemistry, even though only a handful of these coupling reactions were adopted in radiochemical practice. Thus, the implementation of modern synthesis methods like cross-coupling reactions offers the possibility to develop a wide variety of novel radiotracers. The introduction of catalysts based on transition metal complexes bears a high potential for rapid, efficient, highly selective and functional group-tolerating incorporation of carbon-11 and fluorine-18 into target molecules. This review deals with design, application and improvement of transition metal-mediated carbon-carbon as well as carbon-heteroatom cross-coupling reactions as a labeling feature with the focus on the preparation of radiolabeled compounds for molecular imaging. Full article
(This article belongs to the Special Issue Cross-Coupling Reactions in Organic Synthesis)
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264 KiB  
Review
Chemical and Pharmacological Aspects of Capsaicin
by Maria De Lourdes Reyes-Escogido, Edith G. Gonzalez-Mondragon and Erika Vazquez-Tzompantzi
Molecules 2011, 16(2), 1253-1270; https://doi.org/10.3390/molecules16021253 - 28 Jan 2011
Cited by 349 | Viewed by 34660
Abstract
Capsaicin is a unique alkaloid found primarily in the fruit of the Capsicum genus and is what provides its spicy flavor. Generally extracted directly from fruit, high demand has driven the use of established methods to increase production through extraction and characterization. Over [...] Read more.
Capsaicin is a unique alkaloid found primarily in the fruit of the Capsicum genus and is what provides its spicy flavor. Generally extracted directly from fruit, high demand has driven the use of established methods to increase production through extraction and characterization. Over time these methods have improved, usually be applying existing techniques in conjunction. An increasingly wide range of potential applications has increased interest in capsaicin. Especially compelling are the promising results of medical studies showing possible beneficial effects in many diseases. Capsaicin’s pungency has limited its use in clinical trials to support its biological activity. Characterization and extraction/ synthesis of non-pungent analogues is in progress. A review is made of capsaicin research focusing mainly on its production, synthesis, characterization and pharmacology, including some of its main potential clinical uses in humans. Full article
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338 KiB  
Review
Oligomeric Nucleic Acids as Antivirals
by Alessandra Mescalchin and Tobias Restle
Molecules 2011, 16(2), 1271-1296; https://doi.org/10.3390/molecules16021271 - 28 Jan 2011
Cited by 34 | Viewed by 9204
Abstract
Based on the natural functions and chemical characteristics of nucleic acids, a variety of novel synthetic drugs and tools to explore biological systems have become available in recent years. To date, a great number of antisense oligonucleotides, RNA interference-based tools, CpG‑containing oligonucleotides, catalytic [...] Read more.
Based on the natural functions and chemical characteristics of nucleic acids, a variety of novel synthetic drugs and tools to explore biological systems have become available in recent years. To date, a great number of antisense oligonucleotides, RNA interference-based tools, CpG‑containing oligonucleotides, catalytic oligonucleotides, decoys and aptamers has been produced synthetically and applied successfully for understanding and manipulating biological processes and in clinical trials to treat a variety of diseases. Their versatility and potency make them equally suited candidates for fighting viral infections. Here, we describe the different types of nucleic acid-based antivirals, their mechanism of action, their advantages and limitations, and their future prospects. Full article
(This article belongs to the Special Issue Antivirals)
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3416 KiB  
Review
Material Binding Peptides for Nanotechnology
by Urartu Ozgur Safak Seker and Hilmi Volkan Demir
Molecules 2011, 16(2), 1426-1451; https://doi.org/10.3390/molecules16021426 - 09 Feb 2011
Cited by 160 | Viewed by 17422
Abstract
Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. [...] Read more.
Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. This combinatorial approach has also been adapted over the past decade to select material-specific peptides. Screening and selection of such phage displayed material binding peptides has attracted great interest, in particular because of their use in nanotechnology. Phage display selected peptides are either synthesized independently or expressed on phage coat protein. Selected phage particles are subsequently utilized in the synthesis of nanoparticles, in the assembly of nanostructures on inorganic surfaces, and oriented protein immobilization as fusion partners of proteins. In this paper, we present an overview on the research conducted on this area. In this review we not only focus on the selection process, but also on molecular binding characterization and utilization of peptides as molecular linkers, molecular assemblers and material synthesizers. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
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140 KiB  
Review
Flavonoids and the CNS
by Anna K. Jäger and Lasse Saaby
Molecules 2011, 16(2), 1471-1485; https://doi.org/10.3390/molecules16021471 - 10 Feb 2011
Cited by 273 | Viewed by 20380
Abstract
Flavonoids are present in almost all terrestrial plants, where they provide UV-protection and colour. Flavonoids have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. The flavonoids can be divided into several classes depending on [...] Read more.
Flavonoids are present in almost all terrestrial plants, where they provide UV-protection and colour. Flavonoids have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. The flavonoids can be divided into several classes depending on their structure. Flavonoids are present in food and medicinal plants and are thus consumed by humans. They are found in plants as glycosides. Before oral absorption, flavonoids undergo deglycosylation either by lactase phloridzin hydrolase or cytosolic β-glucocidase. The absorbed aglycone is then conjugated by methylation, sulphatation or glucuronidation. Both the aglycones and the conjugates can pass the blood-brain barrier. In the CNS several flavones bind to the benzodiazepine site on the GABAA-receptor resulting in sedation, anxiolytic or anti-convulsive effects. Flavonoids of several classes are inhibitors of monoamine oxidase A or B, thereby working as anti-depressants or to improve the conditions of Parkinson’s patients. Flavanols, flavanones and anthocyanidins have protective effects preventing inflammatory processes leading to nerve injury. Flavonoids seem capable of influencing health and mood. Full article
(This article belongs to the Special Issue Neuroactive Compounds)
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675 KiB  
Review
Plant Polyphenols and Their Anti-Cariogenic Properties: A Review
by Gianmaria F. Ferrazzano, Ivana Amato, Aniello Ingenito, Armando Zarrelli, Gabriele Pinto and Antonino Pollio
Molecules 2011, 16(2), 1486-1507; https://doi.org/10.3390/molecules16021486 - 11 Feb 2011
Cited by 262 | Viewed by 21398
Abstract
Polyphenols constitute one of the most common groups of substances in plants. Polyphenolic compounds have been reported to have a wide range of biological activities, many of which are related to their conventional antioxidant action; however, increasing scientific knowledge has highlighted their potential [...] Read more.
Polyphenols constitute one of the most common groups of substances in plants. Polyphenolic compounds have been reported to have a wide range of biological activities, many of which are related to their conventional antioxidant action; however, increasing scientific knowledge has highlighted their potential activity in preventing oral disease, including the prevention of tooth decay. The aim of this review is to show the emerging findings on the anti-cariogenic properties of polyphenols, which have been obtained from several in vitro studies investigating the effects of these bioactive molecules against Streptococcus mutans, as well as in vivo studies. The analysis of the literature supports the anti-bacterial role of polyphenols on cariogenic streptococci, suggesting (1) a direct effect against S. mutans; (2) an interaction with microbial membrane proteins inhibiting the adherence of bacterial cells to the tooth surface; and (3) the inhibition of glucosyl transferase and amylase. However, more studies, particularly in vivo and in situ, are necessary to establish conclusive evidence for the effectiveness and the clinical applications of these compounds in the prevention of dental caries. It is essential to better determine the nature and distribution of these compounds in our diet and to identify which of the hundreds of existing polyphenols are likely to provide the greatest effects. Full article
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1115 KiB  
Review
Synthesis and Conformation of Substituted Chiral Binaphthyl-Azobenzene Cyclic Dyads with Chiroptical Switching Capabilities
by Kazuto Takaishi and Masuki Kawamoto
Molecules 2011, 16(2), 1603-1624; https://doi.org/10.3390/molecules16021603 - 14 Feb 2011
Cited by 23 | Viewed by 10390
Abstract
Optically active binaphthyl-azobenezene cyclic dyads were synthesized to develop a photochromic switching molecule. Azobenezene moieties were cis-trans isomerized by photoirradiation. As a reflection of the structural change, the specific optical rotation and circular dichroism underwent significant shifts. Under certain conditions, the [...] Read more.
Optically active binaphthyl-azobenezene cyclic dyads were synthesized to develop a photochromic switching molecule. Azobenezene moieties were cis-trans isomerized by photoirradiation. As a reflection of the structural change, the specific optical rotation and circular dichroism underwent significant shifts. Under certain conditions, the positive-negative and zero-positive (or zero-negative) signals were reversed. Optical rotation may potentially be applied in noise-cancelling nondestructive photoswiches. The conformations were studied by experimental and theoretical methods. The results revealed that the helical chirality, (P) or (M), of the cis-azobenzene moiety was induced by intramolecular axial chirality. The twist direction depended on the axial chirality as well as the azobenzene linkage position to the binaphthyls, but was independent of the identity of substituted groups. 2,2’-Linked-(R)-binaphthyl was found to induce cis-(P)-azobenzene, whereas symmetrically 7,7’-linked-(R)-binaphthyl was found to induce cis-(M)-azobenzene. Full article
(This article belongs to the Special Issue Chiroptical Techniques)
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261 KiB  
Review
DNA Libraries for the Construction of Phage Libraries: Statistical and Structural Requirements and Synthetic Methods
by Thomas Lindner, Harald Kolmar, Uwe Haberkorn and Walter Mier
Molecules 2011, 16(2), 1625-1641; https://doi.org/10.3390/molecules16021625 - 15 Feb 2011
Cited by 23 | Viewed by 11545
Abstract
Peptide-based molecular probes identified by bacteriophage (phage) display technology expand the peptide repertoire for in vivo diagnosis and therapy of cancer. Numerous peptides that bind cancer-associated antigens have been discovered by panning phage libraries. However, until now only few of the peptides selected [...] Read more.
Peptide-based molecular probes identified by bacteriophage (phage) display technology expand the peptide repertoire for in vivo diagnosis and therapy of cancer. Numerous peptides that bind cancer-associated antigens have been discovered by panning phage libraries. However, until now only few of the peptides selected by phage display have entered clinical applications. The success of phage derived peptides essentially depends on the quality of the library screened. This review summarizes the methods to achieve highly homogenous libraries that cover a maximal sequence space. Biochemical and chemical strategies for the synthesis of DNA libraries and the techniques for their integration into the viral genome are discussed in detail. A focus is set on the methods that enable the exclusion of disturbing sequences. In addition, the parameters that define the variability, the minimal numbers of copies per library and the use of alternating panning cycles to avoid the loss of selected hits are evaluated. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
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359 KiB  
Review
Design and Screening of M13 Phage Display cDNA Libraries
by Yuliya Georgieva and Zoltán Konthur
Molecules 2011, 16(2), 1667-1681; https://doi.org/10.3390/molecules16021667 - 17 Feb 2011
Cited by 40 | Viewed by 13642
Abstract
The last decade has seen a steady increase in screening of cDNA expression product libraries displayed on the surface of filamentous bacteriophage. At the same time, the range of applications extended from the identification of novel allergens over disease markers to protein-protein interaction [...] Read more.
The last decade has seen a steady increase in screening of cDNA expression product libraries displayed on the surface of filamentous bacteriophage. At the same time, the range of applications extended from the identification of novel allergens over disease markers to protein-protein interaction studies. However, the generation and selection of cDNA phage display libraries is subjected to intrinsic biological limitations due to their complex nature and heterogeneity, as well as technical difficulties regarding protein presentation on the phage surface. Here, we review the latest developments in this field, discuss a number of strategies and improvements anticipated to overcome these challenges making cDNA and open reading frame (ORF) libraries more readily accessible for phage display. Furthermore, future trends combining phage display with next generation sequencing (NGS) will be presented. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
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329 KiB  
Review
Carotenoids and Their Isomers: Color Pigments in Fruits and Vegetables
by Hock-Eng Khoo, K. Nagendra Prasad, Kin-Weng Kong, Yueming Jiang and Amin Ismail
Molecules 2011, 16(2), 1710-1738; https://doi.org/10.3390/molecules16021710 - 18 Feb 2011
Cited by 402 | Viewed by 28451
Abstract
Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as ‘functional food ingredients’. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant [...] Read more.
Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as ‘functional food ingredients’. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables depends on their growth maturity, concentration of carotenoid isomers, and food processing methods. This article focuses more on several carotenoids and their isomers present in different fruits and vegetables along with their concentrations. Carotenoids and their geometric isomers also play an important role in protecting cells from oxidation and cellular damages. Full article
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1815 KiB  
Review
Diversity of Phage-Displayed Libraries of Peptides during Panning and Amplification
by Ratmir Derda, Sindy K.Y. Tang, S. Cory Li, Simon Ng, Wadim Matochko and Mohammad R. Jafari
Molecules 2011, 16(2), 1776-1803; https://doi.org/10.3390/molecules16021776 - 21 Feb 2011
Cited by 153 | Viewed by 20272
Abstract
The amplification of phage-displayed libraries is an essential step in the selection of ligands from these libraries. The amplification of libraries, however, decreases their diversity and limits the number of binding clones that a screen can identify. While this decrease might not be [...] Read more.
The amplification of phage-displayed libraries is an essential step in the selection of ligands from these libraries. The amplification of libraries, however, decreases their diversity and limits the number of binding clones that a screen can identify. While this decrease might not be a problem for screens against targets with a single binding site (e.g., proteins), it can severely hinder the identification of useful ligands for targets with multiple binding sites (e.g., cells). This review aims to characterize the loss in the diversity of libraries during amplification. Analysis of the peptide sequences obtained in several hundred screens of peptide libraries shows explicitly that there is a significant decrease in library diversity that occurs during the amplification of phage in bacteria. This loss during amplification is not unique to specific libraries: it is observed in many of the phage display systems we have surveyed. The loss in library diversity originates from competition among phage clones in a common pool of bacteria. Based on growth data from the literature and models of phage growth, we show that this competition originates from growth rate differences of only a few percent for different phage clones. We summarize the findings using a simple two-dimensional “phage phase diagram”, which describes how the collapse of libraries, due to panning and amplification, leads to the identification of only a subset of the available ligands. This review also highlights techniques that allow elimination of amplification-induced losses of diversity, and how these techniques can be used to improve phage-display selection and enable the identification of novel ligands. Full article
(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)
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1312 KiB  
Review
The Ups and Downs of Tannins as Inhibitors of Poly(ADP-Ribose)glycohydrolase
by Christian Blenn, Philippe Wyrsch and Felix R. Althaus
Molecules 2011, 16(2), 1854-1877; https://doi.org/10.3390/molecules16021854 - 22 Feb 2011
Cited by 30 | Viewed by 8188
Abstract
DNA damage to cells activates nuclear poly(ADP-ribose)polymerases (PARPs) and the poly(ADP-ribose) (PAR) synthesized is rapidly cleaved into ADP-ribose (ADPR) by PAR glycohydrolase (PARG) action. Naturally appearing tannin-like molecules have been implicated in specific inhibition of the PARG enzyme. This review deals with the [...] Read more.
DNA damage to cells activates nuclear poly(ADP-ribose)polymerases (PARPs) and the poly(ADP-ribose) (PAR) synthesized is rapidly cleaved into ADP-ribose (ADPR) by PAR glycohydrolase (PARG) action. Naturally appearing tannin-like molecules have been implicated in specific inhibition of the PARG enzyme. This review deals with the in vitro and in vivo effects of tannins on PAR metabolism and their downstream actions in DNA damage signaling. Full article
(This article belongs to the Special Issue Tannins)
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