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Molecules, Volume 15, Issue 8 (August 2010), Pages 5066-5839

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Open AccessArticle The Protective Effects of the Active Fraction of Shaofu Zhuyu Decoction on Hydrogen Peroxide-Induced Oxidative Injury in Vascular Smooth Muscle Cells
Molecules 2010, 15(8), 5066-5078; doi:10.3390/molecules15085066
Received: 7 July 2010 / Revised: 15 July 2010 / Accepted: 19 July 2010 / Published: 26 July 2010
Cited by 7 | PDF Full-text (431 KB)
Abstract
In this paper, the protective effects of the active fraction (SF-7) from Shaofu Zhuyu decoction (SFZYD) were tested on a hydrogen peroxide (H2O2)-induced rat vascular smooth muscle cells (VSMCs) oxidative injury model. This active fraction (SF-7) shows potent antioxidant
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In this paper, the protective effects of the active fraction (SF-7) from Shaofu Zhuyu decoction (SFZYD) were tested on a hydrogen peroxide (H2O2)-induced rat vascular smooth muscle cells (VSMCs) oxidative injury model. This active fraction (SF-7) shows potent antioxidant properties. The cell viability and oxidative damage markers of VSMCs were determined after exposure to H2O2 for 16 hours. It was observed that SF-7 significantly increased cell survival and reduced apoptosis of H2O2-injured VSMCs. Moreover, SF-7 could markedly increase intracellular superoxide dismutase (SOD) activity and decrease the malondialdehyde (MDA) level in H2O2-injured VSMCs, and suppress the generation of intracellular reactive oxygen species (ROS), as well as intracellular Ca2+ concentration. Thus, SF-7 exhibits protective effects against H2O2-injury on VSMCs, which may be associated with its antioxidant properties. It is suggested that SF may be useful in the treatment of blood stasis syndrome in which oxidative injury is mainly implicated. Full article
Open AccessArticle Functionality Pattern Matching as an Efficient Complementary Structure/Reaction Search Tool: an Open-Source Approach
Molecules 2010, 15(8), 5079-5092; doi:10.3390/molecules15085079
Received: 9 July 2010 / Revised: 22 July 2010 / Accepted: 26 July 2010 / Published: 27 July 2010
Cited by 35 | PDF Full-text (248 KB)
Abstract An open-source software package for creating and operating web-based structure and/or reaction databases is presented. Besides standard search capabilities (text, structure/substructure/similarity), the system offers a fast additional search option, entirely based on binary pattern matching, which uses automatically assigned functional group descriptors. Full article
Open AccessArticle Identification of Two Polysaccharides from Prunella vulgaris L. and Evaluation on Their Anti-Lung Adenocarcinoma Activity
Molecules 2010, 15(8), 5093-5103; doi:10.3390/molecules15085093
Received: 12 May 2010 / Revised: 13 July 2010 / Accepted: 26 July 2010 / Published: 27 July 2010
Cited by 36 | PDF Full-text (161 KB)
Abstract
Prunella vulgaris L. (PV) has been used for tumor therapy in Traditional Chinese Medicine for centuries, however, systematic research on extracted PV polysaccharides believed to possess various biological activities, as well as their preventive and anti-tumor effects on lung cancer has not been
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Prunella vulgaris L. (PV) has been used for tumor therapy in Traditional Chinese Medicine for centuries, however, systematic research on extracted PV polysaccharides believed to possess various biological activities, as well as their preventive and anti-tumor effects on lung cancer has not been reported. In this study, two polysaccharides (P31 and P32) were isolated from the aqueous extract of PV and purified through ethanol precipitation, followed by deproteination using DEAE-52 gel-filtration chromatography. The main monosaccharide composition of polysaccharide P32 was analyzed by GC. It was found that polysaccharide P32 consisted of rhamnose, arabinose, xylose, mannose, glucose and galactose in a molar ratio of 3.46:49.32:58.91:0.43:2.64: 3.11, respectively. In order to evaluate polysaccharide P32’s anti-lung adenocarcinoma activities and immunomodulation effects, a C57BL/6 mouse-Lewis lung carcinoma (LLC) model was established and investigated. Our results showed that polysaccharides of PV had anti-lung cancer activity and could increase the thymus index and the spleen index in tumor-bearing mice, suggesting possible immunomodulation effects. Full article
Open AccessArticle Synthesis and Odor Evaluation of Five New Sulfur-Containing Ester Flavor Compounds from 4-Ethyloctanoic Acid
Molecules 2010, 15(8), 5104-5111; doi:10.3390/molecules15085104
Received: 5 June 2010 / Revised: 16 July 2010 / Accepted: 27 July 2010 / Published: 29 July 2010
Cited by 4 | PDF Full-text (72 KB)
Abstract
Five sulfur-containing flavor compounds were synthesized for the first time by the reaction of 4-ethyloctanoyl chloride with sulfur-containing alcohols or mercaptans. The synthesized compounds are 3-(methylthio)propyl 4-ethyloctanoate, 2-methyl-3-tetrahydro-furanthiol 4-ethyloctanoate, 4-methyl-5-thiazoleethanol 4-ethyloctanoate, 2-furan-methanethiol 4-ethyloctanoate and 2-methyl-3-furanthiol 4-ethyloctanoate. These five synthetic sulfur-containing ester flavor compounds
[...] Read more.
Five sulfur-containing flavor compounds were synthesized for the first time by the reaction of 4-ethyloctanoyl chloride with sulfur-containing alcohols or mercaptans. The synthesized compounds are 3-(methylthio)propyl 4-ethyloctanoate, 2-methyl-3-tetrahydro-furanthiol 4-ethyloctanoate, 4-methyl-5-thiazoleethanol 4-ethyloctanoate, 2-furan-methanethiol 4-ethyloctanoate and 2-methyl-3-furanthiol 4-ethyloctanoate. These five synthetic sulfur-containing ester flavor compounds all have meaty odor and might be used in foods if approved for this purpose in the future. Full article
Open AccessArticle Synthesis and Antiviral Bioactivity of Chiral Thioureas Containing Leucine and Phosphonate Moieties
Molecules 2010, 15(8), 5112-5123; doi:10.3390/molecules15085112
Received: 18 June 2010 / Revised: 26 July 2010 / Accepted: 27 July 2010 / Published: 29 July 2010
Cited by 18 | PDF Full-text (164 KB)
Abstract
A series of novel chiral thioureas 3a-n bearing leucine and phosphonate moieties were synthesized in excellent yields. The structures of the compounds were completely characterized by elemental analysis,IR, 1H-, 13C-, 31P- and 19F-NMR spectral data. A half-leaf
[...] Read more.
A series of novel chiral thioureas 3a-n bearing leucine and phosphonate moieties were synthesized in excellent yields. The structures of the compounds were completely characterized by elemental analysis, IR, 1H-, 13C-, 31P- and 19F-NMR spectral data. A half-leaf method was used to determine the in vivo protective and curative efficacies of the title products against tobacco mosaic virus (TMV). The compounds 3l and 3n displayed good in vivo protection and curative effects against TMV with inhibitory rates of 60.1, 62.8% (protection) and 56.7, 53.6% (curative) at 0.5 mg/mL, respectively. To the best of our knowledge, this is the first report on the antiviral activity of chiral thioureas containing leucine and phosphonate moieties. Full article
Open AccessArticle Antiplatelet Aggregation and Platelet Activating Factor (PAF) Receptor Antagonistic Activities of the Essential Oils of Five Goniothalamus Species
Molecules 2010, 15(8), 5124-5138; doi:10.3390/molecules15085124
Received: 21 June 2010 / Revised: 22 July 2010 / Accepted: 23 July 2010 / Published: 29 July 2010
Cited by 7 | PDF Full-text (143 KB)
Abstract
Nine essential oils, hydrodistilled from different parts of five Goniothalamus species (G. velutinus Airy-Shaw, G. woodii Merr., G. clemensii Ban, G. tapis Miq. and G. tapisoides Mat Salleh) were evaluated for their ability to inhibit platelet aggregation in human whole
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Nine essential oils, hydrodistilled from different parts of five Goniothalamus species (G. velutinus Airy-Shaw, G. woodii Merr., G. clemensii Ban, G. tapis Miq. and G. tapisoides Mat Salleh) were evaluated for their ability to inhibit platelet aggregation in human whole blood using an electrical impedance method and their inhibitory effects on platelet activating factor (PAF) receptor binding with rabbit platelets using 3H-PAF as a ligand. The chemical composition of the oils was analyzed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The bark oil of G. velutinus was the most effective sample as it inhibited both arachidonic acid (AA) and ADP-induced platelet aggregation with IC50 values of 93.6 and 87.7 µg/mL, respectively. Among the studied oils, the bark oils of G. clemensii, G. woodii, G. velutinus and the root oil of G. tapis showed significant inhibitory effects on PAF receptor binding, with IC50 values ranging from 3.5 to 10.5 µg/mL. The strong PAF antagonistic activity of the active oils is related to their high contents of sesquiterpenes and sesquiterpenoids, and the individual components in the oils could possibly produce a synergistic effect in the overall antiplatelet activity of the oils. Full article
Open AccessArticle Hydrogenation of Ethyl Acetate to Ethanol over Ni-Based Catalysts Obtained from Ni/Al Hydrotalcite-Like Compounds
Molecules 2010, 15(8), 5139-5152; doi:10.3390/molecules15085139
Received: 18 June 2010 / Revised: 17 July 2010 / Accepted: 23 July 2010 / Published: 29 July 2010
Cited by 7 | PDF Full-text (544 KB)
Abstract
A series of Ni-based catalysts were prepared using hydrogen reduction of Ni/Al hydrotalcite-like compounds (Ni/Al HTlcs) synthesized by coprecipitation. The physico-chemical properties of Ni/Al hydrotalcite-like compounds and the corresponding Ni-based catalysts were characterized using inductively coupled plasma (ICP), BET surface areas, X-ray diffraction
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A series of Ni-based catalysts were prepared using hydrogen reduction of Ni/Al hydrotalcite-like compounds (Ni/Al HTlcs) synthesized by coprecipitation. The physico-chemical properties of Ni/Al hydrotalcite-like compounds and the corresponding Ni-based catalysts were characterized using inductively coupled plasma (ICP), BET surface areas, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. The results indicated that Ni/Al HTlcs with layered structures could be successfully prepared by the coprecipitation method, and the characteristic HTlcs reflections were also observed in the XRD analysis. The NiO and Ni0 phases were identified in all Ni-based catalysts, which displayed randomly interconnected pores and no layer structures. In addition, the studies also found the Ni/Al HTlcs and Ni-based catalysts had high specific surface areas, low pore volumes and low pore diameters. The catalytic hydrogenation of ethyl acetate to ethanol with Ni-based catalysts was also investigated. Among the studied catalysts, RE1NASH-110-3 showed the highest selectivity and yield of ethyl acetate to ethanol, which were 68.2% and 61.7%, respectively. At the same time, a major by-product, butyl acetate, was formed due to an ester-exchange reaction. A proposed hydrogenation pathway for ethyl acetate over Ni-based catalysts was suggested. Full article
Open AccessArticle Synthesis of β-Maltooligosaccharides of Glycitein and Daidzein and their Anti-Oxidant and Anti-Allergic Activities
Molecules 2010, 15(8), 5153-5161; doi:10.3390/molecules15085153
Received: 10 June 2010 / Revised: 25 July 2010 / Accepted: 27 July 2010 / Published: 29 July 2010
Cited by 9 | PDF Full-text (192 KB)
Abstract
The production of β-maltooligosaccharides of glycitein and daidzein using Lactobacillus delbrueckii and cyclodextrin glucanotransferase (CGTase) as biocatalysts was investigated. The cells of L. delbrueckii glucosylated glycitein and daidzein to give their corresponding 4'- and 7-O-β-glucosides. The β-glucosides of glycitein and daidzein
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The production of β-maltooligosaccharides of glycitein and daidzein using Lactobacillus delbrueckii and cyclodextrin glucanotransferase (CGTase) as biocatalysts was investigated. The cells of L. delbrueckii glucosylated glycitein and daidzein to give their corresponding 4'- and 7-O-β-glucosides. The β-glucosides of glycitein and daidzein were converted into the corresponding  β-maltooligosides by CGTase. The 7-O-β-glucosides of glycitein and daidzein and 7-O-β-maltoside of glycitein showed inhibitory effects on IgE antibody production. On the other hand, β-glucosides of glycitein and daidzein exerted 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity and supeoxide-radical scavenging activity. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Characterization of Destrins with Different Dextrose Equivalents
Molecules 2010, 15(8), 5162-5173; doi:10.3390/molecules15085162
Received: 18 June 2010 / Revised: 12 July 2010 / Accepted: 26 July 2010 / Published: 29 July 2010
Cited by 16 | PDF Full-text (763 KB)
Abstract
Dextrins are widely used for their functional properties and prepared by partial hydrolysis of starch using acid, enzymes, or combinations of both. The physiochemical properties of dextrins are dependent on their molecular distribution and oligosaccharide profiles. In this study, scanning electron microscopy (SEM),
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Dextrins are widely used for their functional properties and prepared by partial hydrolysis of starch using acid, enzymes, or combinations of both. The physiochemical properties of dextrins are dependent on their molecular distribution and oligosaccharide profiles. In this study, scanning electron microscopy (SEM), X-ray diffractometry (XRD), rapid viscoanalysis (RVA), high-performance Liquid Chromatography (HPLC) and gel permeation chromatography (GPC) were used to characterize dextrins prepared by common neutral and thermostable α-amylase hydrolysis. The dextrin granules displayed irregular surfaces and were badly damaged by the enzyme treatment. They displayed A-type X-ray diffraction patterns with a decrease of intensity of the characteristic diffraction peaks. The RVA profiles showed that the viscosity of dextrin decreased with the increase of its Dextrose Equivalent (DE) value. According to HPLC analysis, the molecular weight, degree of polymerization and the composition of oligosaccharides in dextrins were different. Full article
Open AccessArticle Pre-Ischemic Treadmill Training Induces Tolerance to Brain Ischemia: Involvement of Glutamate and ERK1/2
Molecules 2010, 15(8), 5246-5257; doi:10.3390/molecules15085246
Received: 14 July 2010 / Revised: 28 July 2010 / Accepted: 30 July 2010 / Published: 2 August 2010
Cited by 19 | PDF Full-text (237 KB)
Abstract
Physical exercise has been shown to be beneficial in stroke patients and animal stroke models. However, the exact mechanisms underlying this effect are not yet very clear. The present study investigated whether pre-ischemic treadmill training could induce brain ischemic tolerance (BIT) by inhibiting
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Physical exercise has been shown to be beneficial in stroke patients and animal stroke models. However, the exact mechanisms underlying this effect are not yet very clear. The present study investigated whether pre-ischemic treadmill training could induce brain ischemic tolerance (BIT) by inhibiting the excessive glutamate release and event-related kinase 1/2 (ERK1/2) activation observed in rats exposed to middle cerebral artery occlusion (MCAO). Sprague–Dawley rats were divided into three groups (n = 12/group): sham surgery without prior exercise, MCAO without prior exercise and MCAO following three weeks of exercise. Pre-MCAO exercise significantly reduced brain infarct size (103.1 ± 6.7 mm3) relative to MCAO without prior exercise (175.9 ± 13.5 mm3). Similarly, pre-MCAO exercise significantly reduced neurological defects (1.83 ± 0.75) relative to MCAO without exercise (3.00 ± 0.63). As expected, MCAO increased levels of phospho-ERK1/2 (69 ± 5%) relative to sham surgery (40 ± 5%), and phospho-ERK1/2 levels were normalized in rats exposed to pre-ischemic treadmill training (52 ± 6%) relative to MCAO without exercise (69% ± 5%). Parallel effects were observed on striatal glutamate overflow. This study suggests that pre-ischemic treadmill training might induce neuroprotection by inhibiting the phospho-ERK1/2 over-activation and reducing excessive glutamate release. Full article
(This article belongs to the Special Issue Neuroprotective Strategies)
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Open AccessArticle Catalytic Conversion of Cellulose to Levulinic Acid by Metal Chlorides
Molecules 2010, 15(8), 5258-5272; doi:10.3390/molecules15085258
Received: 18 June 2010 / Revised: 14 July 2010 / Accepted: 29 July 2010 / Published: 2 August 2010
Cited by 106 | PDF Full-text (299 KB)
Abstract
The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and
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The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3), exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed. Full article
Open AccessArticle 2-(Penta-1,3-diynyl)-5-(3,4-dihydroxybut-1-ynyl)thiophene, a Novel NQO1 Inducing Agent from Echinops grijsii Hance
Molecules 2010, 15(8), 5273-5281; doi:10.3390/molecules15085273
Received: 15 July 2010 / Revised: 27 July 2010 / Accepted: 2 August 2010 / Published: 3 August 2010
Cited by 6 | PDF Full-text (335 KB) | Supplementary Files
Abstract
A natural alkynol group-substituted thiophene, 2-(penta-1,3-diynyl)-5-(3,4-dihydroxybut-1-ynyl)-thiophene (PDDYT), was isolated from the roots of Echinops grijsii Hance. It possessed potent NAD(P)H: quinone oxidoreductase1 (NQO1) inducing activity and could activate Keap1-Nrf2 pathway effectively in murine hepatoma Hepa 1c1c7 cells. Further investigations indicated that the activation
[...] Read more.
A natural alkynol group-substituted thiophene, 2-(penta-1,3-diynyl)-5-(3,4-dihydroxybut-1-ynyl)-thiophene (PDDYT), was isolated from the roots of Echinops grijsii Hance. It possessed potent NAD(P)H: quinone oxidoreductase1 (NQO1) inducing activity and could activate Keap1-Nrf2 pathway effectively in murine hepatoma Hepa 1c1c7 cells. Further investigations indicated that the activation of Keap1-Nrf2 pathway by PDDYT might be attributed to the activation of Akt and depleting the cellular glutathione (GSH). Full article
Open AccessArticle Chalcones and Dihydrochalcones Augment TRAIL-Mediated Apoptosis in Prostate Cancer Cells
Molecules 2010, 15(8), 5336-5353; doi:10.3390/molecules15085336
Received: 19 May 2010 / Revised: 26 July 2010 / Accepted: 2 August 2010 / Published: 4 August 2010
Cited by 45 | PDF Full-text (1854 KB)
Abstract
Chalcones and dihydrochalcones exhibit chemopreventive and antitumor activity. TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is a natural endogenous anticancer agent. We examined the cytotoxic and apoptotic effect of chalcones and dihydrochalcones on TRAIL-mediated apoptosis in LNCaP prostate cancer cells. The cytotoxicity was evaluated
[...] Read more.
Chalcones and dihydrochalcones exhibit chemopreventive and antitumor activity. TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is a natural endogenous anticancer agent. We examined the cytotoxic and apoptotic effect of chalcones and dihydrochalcones on TRAIL-mediated apoptosis in LNCaP prostate cancer cells. The cytotoxicity was evaluated by the MTT and LDH assays. The apoptosis was detected using annexin V-FITC by flow cytometry and fluorescence microscopy. The ΔΨm was evaluated using DePsipher staining by fluorescence microscopy. Our study showed that two tested chalcones (chalcone and 2’,6’dihydroxy-4’-methoxychalcone) and three dihydrochalcones (2’,6’-dihydroxy-4’4-dimethoxydihydrochalcone, 2’,6’-dihydroxy-4’-methoxydihydro- chalcone,  and 2’,4’,6’-trihydroxydihydrochalcone, called phloretin) markedly augmented TRAIL-induced apoptosis and cytotoxicity in LNCaP cells and confirmed the significant role of chalcones in chemoprevention of prostate cancer. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Effects of Time Point Measurement on the Reconstruction of Gene Regulatory Networks
Molecules 2010, 15(8), 5354-5368; doi:10.3390/molecules15085354
Received: 5 July 2010 / Revised: 30 July 2010 / Accepted: 2 August 2010 / Published: 4 August 2010
Cited by 11 | PDF Full-text (595 KB)
Abstract
With the availability of high-throughput gene expression data in the post-genomic era, reconstruction of gene regulatory networks has become a hot topic. Regulatory networks have been intensively studied over the last decade and many software tools are currently available. However, the impact of
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With the availability of high-throughput gene expression data in the post-genomic era, reconstruction of gene regulatory networks has become a hot topic. Regulatory networks have been intensively studied over the last decade and many software tools are currently available. However, the impact of time point selection on network reconstruction is often underestimated. In this paper we apply the Dynamic Bayesian network (DBN) to construct the Arabidopsis gene regulatory networks by analyzing the time-series gene microarray data. In order to evaluate the impact of time point measurement on network reconstruction, we deleted time points one by one to yield 11 distinct groups of incomplete time series. Then the gene regulatory networks constructed based on complete and incomplete data series are compared in terms of statistics at different levels. Two time points are found to play a significant role in the Arabidopsis gene regulatory networks. Pathway analysis of significant nodes revealed three key regulatory genes. In addition, important regulations between genes, which were insensitive to the time point measurement, were also identified. Full article
(This article belongs to the Special Issue From Computational Chemistry to Complex Networks)
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Open AccessArticle Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid
Molecules 2010, 15(8), 5369-5377; doi:10.3390/molecules15085369
Received: 1 June 2010 / Revised: 21 July 2010 / Accepted: 26 July 2010 / Published: 5 August 2010
Cited by 2 | PDF Full-text (333 KB)
Abstract
The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high
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The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols and β-keto esters make this novel carbon based acid one of the best choices for the reaction. Full article
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Open AccessArticle Simultaneous Determination of Flavonoids in Different Parts of Citrus reticulata ‘Chachi’ Fruit by High Performance Liquid Chromatography—Photodiode Array Detection
Molecules 2010, 15(8), 5378-5388; doi:10.3390/molecules15085378
Received: 12 July 2010 / Revised: 27 July 2010 / Accepted: 2 August 2010 / Published: 5 August 2010
Cited by 25 | PDF Full-text (238 KB)
Abstract
Flavonoids are important polyphenolic secondary metabolites in plant. Citrus reticulata ‘Chachi’ fruit are rich in flavonoids and are being used as functional antioxidant ingredients for the treatment of atherosclerosis and cancer, etc. A high performance liquid chromatography-photodiode array detection system was used
[...] Read more.
Flavonoids are important polyphenolic secondary metabolites in plant. Citrus reticulata ‘Chachi’ fruit are rich in flavonoids and are being used as functional antioxidant ingredients for the treatment of atherosclerosis and cancer, etc. A high performance liquid chromatography-photodiode array detection system was used to analyze five flavonoids, namely, naringin, hesperidin, didymin, tangeretin and nobiletin, in different parts of C. reticulata ‘Chachi’ fruit. The chromatographic analysis was performed on a C18 column with a gradient elution of acetonitrile and water at a flow rate of 1.0 mL/min. Detection was carried out using a photodiode array detector at 280 nm. The calibration curves for the determination of all analytes showed good linearity over the investigated ranges (R2 > 0.9995). Precision and reproducibility were evaluated by six replicated analyses, and the R.S.D. values were less than 0.9% and 2.7%. The recoveries were between 98.37 and 103.89%. This method is promising to improve the quality control of different parts of C. reticulata ‘Chachi’ fruit. Full article
Open AccessArticle Using Topological Indices to Predict Anti-Alzheimer and Anti-Parasitic GSK-3 Inhibitors by Multi-Target QSAR in Silico Screening
Molecules 2010, 15(8), 5408-5422; doi:10.3390/molecules15085408
Received: 8 June 2010 / Revised: 27 July 2010 / Accepted: 2 August 2010 / Published: 9 August 2010
Cited by 11 | PDF Full-text (330 KB)
Abstract
Plasmodium falciparum, Leishmania, Trypanosomes, are the causers of diseases such as malaria, leishmaniasis and African trypanosomiasis that nowadays are the most serious parasitic health problems worldwide. The great number of deaths and the few drugs available against these parasites, make
[...] Read more.
Plasmodium falciparum, Leishmania, Trypanosomes, are the causers of diseases such as malaria, leishmaniasis and African trypanosomiasis that nowadays are the most serious parasitic health problems worldwide. The great number of deaths and the few drugs available against these parasites, make necessary the search for new drugs. Some of these antiparasitic drugs also are GSK-3 inhibitors. GSKI-3 are candidates to develop drugs for the treatment of Alzheimer’s disease. In this work topological descriptors for a large series of 3,370 active/non-active compounds were initially calculated with the ModesLab software. Linear Discriminant Analysis was used to fit the classification function and it predicts heterogeneous series of compounds like paullones, indirubins, meridians, etc. This study thus provided a general evaluation of these types of molecules. Full article
(This article belongs to the Special Issue From Computational Chemistry to Complex Networks)
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Open AccessArticle Antioxidant Activity of Butyl- and Phenylstannoxanes Derivedfrom 2-, 3- and 4-Pyridinecarboxylic Acids
Molecules 2010, 15(8), 5445-5459; doi:10.3390/molecules15085445
Received: 7 May 2010 / Revised: 31 May 2010 / Accepted: 15 July 2010 / Published: 9 August 2010
Cited by 18 | PDF Full-text (220 KB)
Abstract
In vitro antioxidant activity for 12 stannoxanes derived from Ph3SnCl (compounds 1-3), Ph2SnCl2 (compounds 4-6), Bu3SnCl (compounds 7-9), and Bu2SnCl2 (compounds 10-12
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In vitro antioxidant activity for 12 stannoxanes derived from Ph3SnCl (compounds 1-3), Ph2SnCl2 (compounds 4-6), Bu3SnCl (compounds 7-9), and Bu2SnCl2 (compounds 10-12), was assayed qualitatively by the chromatographic profile with 1,1-diphenyl-2-picrylhydrazil (DPPH) method and by two quantitative methods: the DPPH radical scavenging activity and Ferric-Reducing Antioxidant Power (FRAP) assays. The results were compared with those obtained with the starting materials 2-pyridine- carboxylic acid (I), 3-pyridinecarboxylic acid (II) and 4-pyridinecarboxylic acid (III), as well as with standard compounds, such as vitamin C and vitamin E, respectively. The in vitro antiradical activity with DPPH of diphenyltin derivative 5 showed a very similar behavior to vitamin C at a 20 µg/mL concentration, whereas according to the FRAP method, compound 8 was better. This difference is due to the mechanism of the antioxidant process. The Structure-Activity Relationships (SAR) for both methods is also reported. Full article
(This article belongs to the Special Issue Antioxidants)
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Open AccessArticle Seasonal Variation, Chemical Composition, and Analgesic and Antimicrobial Activities of the Essential Oil from Leaves of Tetradenia riparia (Hochst.) Codd in Southern Brazil
Molecules 2010, 15(8), 5509-5524; doi:10.3390/molecules15085509
Received: 24 June 2010 / Revised: 4 August 2010 / Accepted: 6 August 2010 / Published: 10 August 2010
Cited by 29 | PDF Full-text (337 KB)
Abstract
The seasonal variation of the chemical composition of the essential oil from fresh leaves of Tetradenia riparia (Hochst.) Codd grown in southern Brazil was analyzed by GC-MS, and the analgesic and antimicrobial activities of this oil were assayed. The yield of essential oil
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The seasonal variation of the chemical composition of the essential oil from fresh leaves of Tetradenia riparia (Hochst.) Codd grown in southern Brazil was analyzed by GC-MS, and the analgesic and antimicrobial activities of this oil were assayed. The yield of essential oil ranged from 0.17% to 0.26%, with the maximum amount in winter and the minimum in spring. The results obtained from principal components analysis (PCA) revealed the existence of high chemical variability in the different seasons. The samples were clearly discriminated into three groups: winter, autumn, and spring-summer. Samples collected during winter contained the highest percentages of calyculone (24.70%), abietadiene (13.54%), and viridiflorol (4.20%). In autumn, the major constituents were ledol (8.74%) and cis-muurolol-5-en-4-α-ol (13.78%). Samples collected in spring-summer contained the highest percentages of fenchone (12.67%), 14-hydroxy-9-epi-caryophyllene (24.36%), and α-cadinol (8.33%). Oxygenated sesquiterpenes were predominant in all the samples analyzed. The observed chemovariation might be environmentally determined by a seasonal influence. The essential oil, when given orally at a dose of 200 mg/kg, exhibited good analgesic activity on acetic acid-induced writhing in mice, inhibiting the constrictions by 38.94% to 46.13%, and this effect was not affected by seasonal variation. The antimicrobial activity of the essential oil against the bacterial strains: Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Klebsiella pneumonia, Proteus mirabilis, Morganella morganii, and Enterobacter cloacae, and the pathogenic fungus Candida albicans was assessed by the disc diffusion method and determination of the minimum inhibitory concentration. The results obtained, followed by measurement of the minimum inhibitory concentration (MIC), indicated that S. aureus, B. subtilis, and Candida albicans were the most sensitive microorganisms, showing largest inhibition, and the lowest MIC values varied from 15.6 to 31.2 µg/mL, 7.8 to 15.6 µg/mL, and 31.2 to 62.5 µg/mL, respectively. Full article
Open AccessArticle Chemical Constituents with Free-Radical-Scavenging Activities from the Stem of Microcos paniculata
Molecules 2010, 15(8), 5547-5560; doi:10.3390/molecules15085547
Received: 15 July 2010 / Revised: 2 August 2010 / Accepted: 4 August 2010 / Published: 12 August 2010
Cited by 14 | PDF Full-text (339 KB)
Abstract
The free-radical-scavenging activities of various solvent extracts of Microcos paniculata were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and Co (II) EDTA-induced luminol chemiluminescence by flow injection. In all three of these systems the ethyl acetate (EtOAc) extract
[...] Read more.
The free-radical-scavenging activities of various solvent extracts of Microcos paniculata were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and Co (II) EDTA-induced luminol chemiluminescence by flow injection. In all three of these systems the ethyl acetate (EtOAc) extract showed the highest free-radical-scavenging activity compared with the other three (n-BuOH, water and petroleum ether) extracts. Free-radical-scavenging assay-guided chromatographic separation of the EtOAc extract, using a normal-phase and reverse-phase silica gel column chromatography yielded five compounds: a new triterpene named methyl 3b-O-p-hydroxy-E-cinnamoyloxy-2a,23-dihydroxyolean-12-en-28-oate (1), whose spectral data are presented for the first time, together with four known compounds, epicatechin (2), 3-trans-feruloyl maslinic acid (3), maslinic acid (4) and sucrose (5). All of the compounds were isolated from Microcos paniculata for the first time. The compounds were identified by spectroscopic methods. Among them, compound 2 displayed significant free-radical-scavenging activity which is similar to that of standard antioxidant ascorbic acid (VC) and therefore may be a promising natural antioxidant. Full article
Open AccessArticle A Simple, Safe and Efficient Synthesis of Tyrian Purple (6,6′-Dibromoindigo)
Molecules 2010, 15(8), 5561-5580; doi:10.3390/molecules15085561
Received: 18 June 2010 / Revised: 3 August 2010 / Accepted: 5 August 2010 / Published: 12 August 2010
Cited by 3 | PDF Full-text (229 KB)
Abstract
6,6’-Dibromoindigo is a major component of the historic pigment Tyrian purple, arguably the most famous dye of antiquity. Over the last century, chemists have been interested in developing practical syntheses of the compound We describe herein a new, reasonably simple and efficient synthesis
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6,6’-Dibromoindigo is a major component of the historic pigment Tyrian purple, arguably the most famous dye of antiquity. Over the last century, chemists have been interested in developing practical syntheses of the compound We describe herein a new, reasonably simple and efficient synthesis of Tyrian purple which opens the way to the production of large quantities of the dye with minimal hazards and at low cost. Full article
Open AccessArticle Enantioselctive Syntheses of Sulfur Analogues of Flavan-3-Ols
Molecules 2010, 15(8), 5595-5619; doi:10.3390/molecules15085595
Received: 26 July 2010 / Revised: 12 August 2010 / Accepted: 12 August 2010 / Published: 13 August 2010
Cited by 8 | PDF Full-text (194 KB)
Abstract
The first enantioselective syntheses of sulfur flavan-3-ol analogues 18 have been accomplished, whereby the oxygen atom of the pyran ring has been replaced by a sulfur atom. The key steps were: (a) Pd(0) catalyzed introduction of –St-butyl group, (b)
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The first enantioselective syntheses of sulfur flavan-3-ol analogues 18 have been accomplished, whereby the oxygen atom of the pyran ring has been replaced by a sulfur atom. The key steps were: (a) Pd(0) catalyzed introduction of –S t-butyl group, (b) Sharpless enantioselective dihydroxylation of the alkene, (c) acid catalyzed ring closure to produce the thiopyran ring, and (d) removal of benzyl groups using N,N-dimethylaniline and AlCl3. The compounds were isolated in high chemical and optical purity. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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Open AccessArticle Synthesis and Characterization of Azo Compounds and Study of the Effect of Substituents on Their Liquid Crystalline Behavior
Molecules 2010, 15(8), 5620-5628; doi:10.3390/molecules15085620
Received: 1 July 2010 / Revised: 4 August 2010 / Accepted: 12 August 2010 / Published: 13 August 2010
Cited by 15 | PDF Full-text (334 KB)
Abstract
In this paper we present six select mesomorphic azo compounds distinguished by the presence of diverse substituents on a central benzene nucleus. All the synthesized compounds exhibit enantiotropic mesophases. The mesomorphic properties of the substituted compounds were compared with those of the unsubstituted
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In this paper we present six select mesomorphic azo compounds distinguished by the presence of diverse substituents on a central benzene nucleus. All the synthesized compounds exhibit enantiotropic mesophases. The mesomorphic properties of the substituted compounds were compared with those of the unsubstituted parent compound to evaluate the effect of the nature and position of the substituents on mesomorphism. Full article
Open AccessArticle Synthesis and Biological Evaluation of 2,5-Bis(alkylamino)-1,4-benzoquinones
Molecules 2010, 15(8), 5629-5643; doi:10.3390/molecules15085629
Received: 14 June 2010 / Revised: 14 July 2010 / Accepted: 16 July 2010 / Published: 13 August 2010
Cited by 14 | PDF Full-text (169 KB)
Abstract
A series of twelve 2,5-bis(alkylamino)-1,4-benzoquinones were prepared in yields ranging from 9–58% via the reaction between p-benzoquinone and various amines. The structures of the synthesized compounds were confirmed by IR, 1H- and 13C-NMR and MS analyses. The phytotoxicity of the
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A series of twelve 2,5-bis(alkylamino)-1,4-benzoquinones were prepared in yields ranging from 9–58% via the reaction between p-benzoquinone and various amines. The structures of the synthesized compounds were confirmed by IR, 1H- and 13C-NMR and MS analyses. The phytotoxicity of the 2,5-bis(alkylamino)-1,4-benzoquinones was evaluated against two crop species, Cucumis sativus and Sorgum bicolor, at 1.0 × 10-3 mol/L. In general, the quinones displayed inhibitory effects on the dicotyledonous species C. sativus (7–74%). On the other hand stimulatory effects were observed on S. bicolor (monocotyledonous). Similar results were observed in the biological assays carried out with the weed species Ipomoea grandifolia (dicotyledonous) and Brachiaria decumbens (monocotyledonous). In addition, the cytotoxicity of the 2,5-bis(alkylamino)-1,4-benzoquinones was assayed against HL-60 (leukemia), MDA-MB-435 (melanoma), SF-295 (brain) and HCT-8 (colon) human cancer cell lines and human peripheral blood mononuclear cells (PBMC), as representatives of healthy cells, using a MTT and an Alamar Blue assay. Compound 12 was the most active, displaying cytotoxicity against all cancer cell lines tested. Full article
Open AccessArticle Study of Cyclic Quaternary Ammonium Bromides by B3LYP Calculations, NMR and FTIR Spectroscopies
Molecules 2010, 15(8), 5644-5657; doi:10.3390/molecules15085644
Received: 26 July 2010 / Revised: 11 August 2010 / Accepted: 13 August 2010 / Published: 16 August 2010
Cited by 6 | PDF Full-text (306 KB)
Abstract
N,N-dioctyl-azepanium, -piperidinium and -pyrrolidinium bromides 1-3, have been obtained and characterized by FTIR and NMR spectroscopy. DFT calculations have also been carried out. The optimized bond lengths, bond angles and torsion angles calculated by B3LYP/6-31G(d,p) approach have been presented.
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N,N-dioctyl-azepanium, -piperidinium and -pyrrolidinium bromides 1-3, have been obtained and characterized by FTIR and NMR spectroscopy. DFT calculations have also been carried out. The optimized bond lengths, bond angles and torsion angles calculated by B3LYP/6-31G(d,p) approach have been presented. Both FTIR and Raman spectra of 1-3 are consistent with the calculated structures in the gas phase. The screening constants for 13C and 1H atoms have been calculated by the GIAO/B3LYP/6-31G(d,p) approach and analyzed. Linear correlations between the experimental 1H and 13C chemical shifts and the computed screening constants confirm the optimized geometry. Full article
(This article belongs to the Section Organic Synthesis)
Open AccessArticle Antioxidant Tannins from Stem Bark and Fine Root of Casuarina equisetifolia
Molecules 2010, 15(8), 5658-5670; doi:10.3390/molecules15085658
Received: 21 July 2010 / Revised: 10 August 2010 / Accepted: 13 August 2010 / Published: 16 August 2010
Cited by 8 | PDF Full-text (360 KB)
Abstract
Structures of condensed tannins from the stem bark and fine root of Casuarina equisetifolia were identified using MALDI-TOF MS and HPLC analyses. The condensed tannins from stem bark and fine root consist predominantly of procyanidin combined with prodelphinidin and propelargonidin, and epicatechin is
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Structures of condensed tannins from the stem bark and fine root of Casuarina equisetifolia were identified using MALDI-TOF MS and HPLC analyses. The condensed tannins from stem bark and fine root consist predominantly of procyanidin combined with prodelphinidin and propelargonidin, and epicatechin is the main extension unit. The condensed tannins had different polymer chain lengths, varying from trimers to tridecamer for stem bark and to pentadecamer for fine root. The antioxidant activities were measured by two models: 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing/ antioxidant power  (FRAP). The condensed tannins extracted from C. equisetifolia showed very good DPPH radical scavenging activity and ferric reducing/ antioxidant power, suggesting that these extracts may be considered as new sources of natural antioxidants for food and nutraceutical products. Full article
(This article belongs to the Special Issue Tannins)
Open AccessCommunication Synthesis, Identification and Anti-Cancer Activity of 1-(4-Methylpent-2-enyl)-2-(4-phenylbut-2-enyl)disulfane
Molecules 2010, 15(8), 5671-5679; doi:10.3390/molecules15085671
Received: 8 July 2010 / Revised: 5 August 2010 / Accepted: 9 August 2010 / Published: 16 August 2010
Cited by 1 | PDF Full-text (348 KB)
Abstract
In this study, we synthesized 1-(4-methylpent-2-enyl)-2-(4-phenylbut-2- enyl)disulfane using sodium sulfide, 1-bromine-4-methyl-2-amylene and 1-(4-bromine-2- butylene)benzene as raw materials. The yield rate of target product was 84%. The structure of the target product was confirmed by GC-MS, 1H-NMR and elemental analysis. The results of
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In this study, we synthesized 1-(4-methylpent-2-enyl)-2-(4-phenylbut-2- enyl)disulfane using sodium sulfide, 1-bromine-4-methyl-2-amylene and 1-(4-bromine-2- butylene)benzene as raw materials. The yield rate of target product was 84%. The structure of the target product was confirmed by GC-MS, 1H-NMR and elemental analysis. The results of anti-cancer activity experiments showed that 1-(4-methylpent-2-enyl)-2-(4- phenylbut-2-enyl)disul-fane could significantly inhibit the proliferation, induce the apoptosis of CNE2 cells in a dose dependent manner, and could significantly enhance the activity of XIAP. Full article
Open AccessArticle A Facile Synthesis of 3-Substituted 9H-Pyrido[3,4-b]indol-1(2H)-one Derivatives from 3-Substituted β-Carbolines
Molecules 2010, 15(8), 5680-5691; doi:10.3390/molecules15085680
Received: 2 August 2010 / Revised: 10 August 2010 / Accepted: 11 August 2010 / Published: 17 August 2010
Cited by 5 | PDF Full-text (369 KB)
Abstract
A mild and efficient two-step synthesis of 3-substituted β-carbolinone derivatives from 3-substituted β-carboline in good yields is described. A possible reaction mechanism for the formation of the skeleton of β-carbolin-1-one is proposed. The structures of these compounds were established by IR, 1H-NMR,
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A mild and efficient two-step synthesis of 3-substituted β-carbolinone derivatives from 3-substituted β-carboline in good yields is described. A possible reaction mechanism for the formation of the skeleton of β-carbolin-1-one is proposed. The structures of these compounds were established by IR, 1H-NMR, 13C-NMR, mass spectrometry and elemental analysis, as well as X-ray crystallographic analysis of 4-2 and 6-2. Full article
Open AccessArticle Solid-Phase Synthesis of Oligodeoxynucleotides Containing N4-[2-(t-butyldisulfanyl)ethyl]-5-methylcytosine Moieties
Molecules 2010, 15(8), 5692-5707; doi:10.3390/molecules15085692
Received: 28 May 2010 / Revised: 28 July 2010 / Accepted: 5 August 2010 / Published: 18 August 2010
Cited by 5 | PDF Full-text (253 KB) | Supplementary Files
Abstract
An efficient route for the synthesis of the phosphoramidite derivative of 5-methylcytosine bearing a tert-butylsulfanyl group protected thiol is described. This building block is used for the preparation of oligonucleotides carrying a thiol group at the nucleobase at the internal position of
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An efficient route for the synthesis of the phosphoramidite derivative of 5-methylcytosine bearing a tert-butylsulfanyl group protected thiol is described. This building block is used for the preparation of oligonucleotides carrying a thiol group at the nucleobase at the internal position of a DNA sequence. The resulting thiolated oligonucleotides are useful intermediates to generate oligonucleotide conjugates carrying molecules of interest at internal positions of a DNA sequence. Full article
(This article belongs to the Special Issue Solid Phase Synthesis)
Open AccessArticle Synthesis and Application of a 2-[(4-Fluorophenyl)-sulfonyl]ethoxy Carbonyl(Fsec) Protected Glycosyl Donor in Carbohydrate Chemistry
Molecules 2010, 15(8), 5708-5720; doi:10.3390/molecules15085708
Received: 9 June 2010 / Revised: 10 August 2010 / Accepted: 18 August 2010 / Published: 19 August 2010
PDF Full-text (493 KB)
Abstract
The 2-[(4-fluorophenyl)sulfonyl]ethoxy carbonyl (Fsec) group for protection of hydroxyl groups has been designed, synthesized, and evaluated. Fsec-Cl was readily prepared in 91% yield over three steps and subsequently used to protect 4-fluorobenzyl alcohol in high yield. The Fsec group was cleaved from the
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The 2-[(4-fluorophenyl)sulfonyl]ethoxy carbonyl (Fsec) group for protection of hydroxyl groups has been designed, synthesized, and evaluated. Fsec-Cl was readily prepared in 91% yield over three steps and subsequently used to protect 4-fluorobenzyl alcohol in high yield. The Fsec group was cleaved from the resulting model compound under mild basic conditions e.g., 20% piperidine in DMF and was stable under acidic conditions, e.g., neat acetic acid. The Fsec group was used to protect the unreactive 4-OH in a galactose building block that was later used in the synthesis of 6-aminohexyl galabioside. Full article
(This article belongs to the Special Issue Protecting Group in Organic Synthesis)
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Open AccessArticle Design, Synthesis, and Biological Evaluation of Benzylamino-Methanone Based Cholesteryl Ester Transfer Protein Inhibitors
Molecules 2010, 15(8), 5721-5733; doi:10.3390/molecules15085721
Received: 18 June 2010 / Revised: 10 August 2010 / Accepted: 13 August 2010 / Published: 19 August 2010
Cited by 6 | PDF Full-text (331 KB)
Abstract
Cholesteryl ester transfer protein (CETP) is a glycoprotein involved in transporting lipoprotein particles and neutral lipids between high-density lipoprotein (HDL) and low density lipoproteins (LDL) and therefore its a proper target for treating dyslipidemia and related disorders. Guided by our previosuly-reported pharmacophore and
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Cholesteryl ester transfer protein (CETP) is a glycoprotein involved in transporting lipoprotein particles and neutral lipids between high-density lipoprotein (HDL) and low density lipoproteins (LDL) and therefore its a proper target for treating dyslipidemia and related disorders. Guided by our previosuly-reported pharmacophore and QSAR models for CETP inhibition, we synthesized and bioassayed a series of benzylamino-methanones. The most potent illustrated 30% CETP inhibition at 10 μM. Full article
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Open AccessArticle Chemical Composition and Larvicidal Activity against Aedes aegypti Larvae of Essential Oils from Four Guarea Species
Molecules 2010, 15(8), 5734-5741; doi:10.3390/molecules15085734
Received: 6 July 2010 / Revised: 31 July 2010 / Accepted: 5 August 2010 / Published: 19 August 2010
Cited by 17 | PDF Full-text (165 KB)
Abstract
The essential oils of four Guarea species collected at Manaus (Amazonas, Brazil) were obtained by hydrodistillation and analyzed by GC-MS. Except for one diterpene detected, the compounds identified in the essential oils were hydrocarbons and oxygenated sesquiterpenes. The major sesquiterpenes were α-santalene (26.26%)
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The essential oils of four Guarea species collected at Manaus (Amazonas, Brazil) were obtained by hydrodistillation and analyzed by GC-MS. Except for one diterpene detected, the compounds identified in the essential oils were hydrocarbons and oxygenated sesquiterpenes. The major sesquiterpenes were α-santalene (26.26%) and α-copaene (14.61%) from G. convergens branches; caryophyllene epoxide (40.91%) and humulene epoxide II (14.43%) from G. humaitensis branches; cis-caryophyllene (33.37%) and α-trans-bergamotene (11.88%) from G. scabra leaves; caryophyllene epoxide (36.54%) in leaves and spathulenol (14.34%) in branches from G. silvatica. The diterpene kaurene (15.61%) was found in G. silvatica leaves. Larvicidal activity assay of essential oils against third-instar Aedes aegypti larvae revealed that at higher concentrations (500 and 250 μg/mL), all the essential oils caused 100% mortality after 24 h of exposure. The most active essential oils were those of G. humaitensis branches (LC50 48.6 μg/mL), G. scabra leaves (LC50 98.6 μg/mL) and G. silvatica (LC50 117.9 μg/mL). The differences in the toxicity of essential oils of Guarea species on A. aegypti are due to qualitative and quantitative variations of the components, therefore the larvicidal effect may be due to higher amount of the sesquiterpenes with caryophyllane skeleton. Full article
(This article belongs to the Special Issue Phytochemicals with Signaling, Medicinal and Therapeutic Properties)
Open AccessArticle Development of a Sphingosylphosphorylcholine Detection System Using RNA Aptamers
Molecules 2010, 15(8), 5742-5755; doi:10.3390/molecules15085742
Received: 27 July 2010 / Revised: 16 August 2010 / Accepted: 17 August 2010 / Published: 20 August 2010
Cited by 5 | PDF Full-text (309 KB)
Abstract
Sphingosylphosphorylcholine (SPC) is a lysosphingolipid that exerts multiple functions, including acting as a spasmogen, as a mitogenic factor for various types of cells, and sometimes as an inflammatory mediator. Currently, liquid chromatography/tandem mass spectrometry (LC/MS/MS) is used for the quantitation of SPC. However,
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Sphingosylphosphorylcholine (SPC) is a lysosphingolipid that exerts multiple functions, including acting as a spasmogen, as a mitogenic factor for various types of cells, and sometimes as an inflammatory mediator. Currently, liquid chromatography/tandem mass spectrometry (LC/MS/MS) is used for the quantitation of SPC. However, because of the complicated procedures required it may not be cost effective, hampering its regular usage in a routine practical SPC monitoring. In this report, we have generated RNA aptamers that bind to SPC with high affinity using an in vitro selection procedure and developed an enzyme-linked aptamer assay system using the minimized SPC aptamer that can successfully distinguish SPC from the structurally related sphingosine 1-phosphate (S1P). This is the first case of the Systematic Evolution of Ligands by EXponential enrichment (SELEX) process being performed with a lysosphingolipid. The SPC aptamers would be valuable tools for the development of aptamer-based medical diagnosis and for elucidating the biological role of SPC. Full article
Open AccessArticle Organic-Inorganic Hybrid Silica Material Derived from a Monosilylated Grubbs-Hoveyda Ruthenium Carbene as a Recyclable Metathesis Catalyst
Molecules 2010, 15(8), 5756-5767; doi:10.3390/molecules15085756
Received: 28 June 2010 / Revised: 10 August 2010 / Accepted: 18 August 2010 / Published: 23 August 2010
Cited by 11 | PDF Full-text (289 KB)
Abstract
The synthesis of a monosilylated Grubbs-Hoveyda ruthenium alkylidene complex is described, as well as the preparation and characterization of the corresponding material by sol-gel cogelification with tetraethoxysilane (TEOS) and the assay of this recyclable supported catalyst in ring-closing diene and enyne metathesis reactions
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The synthesis of a monosilylated Grubbs-Hoveyda ruthenium alkylidene complex is described, as well as the preparation and characterization of the corresponding material by sol-gel cogelification with tetraethoxysilane (TEOS) and the assay of this recyclable supported catalyst in ring-closing diene and enyne metathesis reactions under thermal and microwave conditions. Full article
(This article belongs to the Special Issue Ring-Closing Metathesis)
Open AccessArticle Asymmetric Synthesis of α-Aminophosphonates Using the Inexpensive Chiral Catalyst 1,1’-Binaphthol Phosphate
Molecules 2010, 15(8), 5782-5796; doi:10.3390/molecules15085782
Received: 19 June 2010 / Revised: 18 August 2010 / Accepted: 20 August 2010 / Published: 24 August 2010
Cited by 13 | PDF Full-text (267 KB)
Abstract Asymmetric addition under mild conditions of dialkyl phosphites on aldimines derived from cinnamaldehyde catalyzed by the inexpensive chiral organocatalyst (R)-3,3’-[4-fluorophenyl]2-1,1’-binaphthol phosphate has been found effective to give new α-amino-phosphonates 9 in moderate yields (30–65%) and enantiomeric excess (8.4%–61.9%). Full article
Open AccessArticle Yields and Constituents of Essential Oil from Cones of Pinaceae spp. Natively Grown in Turkey
Molecules 2010, 15(8), 5797-5806; doi:10.3390/molecules15085797
Received: 15 July 2010 / Revised: 17 August 2010 / Accepted: 23 August 2010 / Published: 24 August 2010
Cited by 22 | PDF Full-text (156 KB)
Abstract
In this study, the yields and composition of essential oils obtained from the cones of Pinaceae family species natively grown in Turkey were investigated. Essential oils were obtained by hydrodistillation. Oil yields were 0.13-0.48 mL/100 g in pine cones, 0.42-0.59 mL/100g in fir,
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In this study, the yields and composition of essential oils obtained from the cones of Pinaceae family species natively grown in Turkey were investigated. Essential oils were obtained by hydrodistillation. Oil yields were 0.13-0.48 mL/100 g in pine cones, 0.42-0.59 mL/100g in fir, 0.36 mL/100g in spruce and 0.37 mL/100g in cedar. While a-pinene (47.1-14.8%) was the main constituent of P. slyvestris, P. nigra and P. halepensis, limonene (62.8%) in P. pinea and b-pinene (39.6%) in P. brutia were found in higher amounts. Like in P. pinea, limonene was the main compound in Cedrus libani (22.7%). In fir species the major compounds were a-pinene (70.6-53.0%) and b-pinene (10.9-8.2%). Contrary to other species b-pinene (32.7%) was found as a major compound in Picea orientalis. Full article
(This article belongs to the Section Natural Products)
Open AccessArticle Antimicrobial and Antioxidant Activities of the Root Bark Essential Oil of Periploca sepium and Its Main Component 2-Hydroxy-4-methoxybenzaldehyde
Molecules 2010, 15(8), 5807-5817; doi:10.3390/molecules15085807
Received: 5 August 2010 / Revised: 16 August 2010 / Accepted: 23 August 2010 / Published: 24 August 2010
Cited by 34 | PDF Full-text (216 KB)
Abstract
The root bark essential oil of Periploca sepium Bunge (Asclepiadaceae/ Apocynaceae) obtained by hydrodistillation was investigated by GC and GC-MS. 2-Hydroxy-4-methoxybenzaldehyde was found to be the main component (78.8% of the total) among 17 identified compounds. 2-Hydroxy-4-methoxybenzaldehyde was separated and purified by preparative
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The root bark essential oil of Periploca sepium Bunge (Asclepiadaceae/ Apocynaceae) obtained by hydrodistillation was investigated by GC and GC-MS. 2-Hydroxy-4-methoxybenzaldehyde was found to be the main component (78.8% of the total) among 17 identified compounds. 2-Hydroxy-4-methoxybenzaldehyde was separated and purified by preparative thin layer chromatography, and was further identified by means of physicochemical and spectrometric analysis. Both the essential oil and 2-hydroxy-4-methoxybenzaldehyde exhibited antimicrobial activities on all test bacteria and fungi, with MBC/MFC values ranging from 125 μg/mL to 300 μg/mL, MIC values from 80 μg/mL to 300 μg/mL, and IC50 values from 63.29 μg/mL to 167.30 μg/mL. They also showed moderate antioxidant activity in the DPPH free radical scavenging, β-carotene bleaching and ferrozine-ferrous ions assays. The results indicated that the major portion of these antimicrobial and antioxidant activities was due to the presence of 2-hydroxy-4-methoxy-benzaldehyde in the oil, which could potentially be developed as an antimicrobial and antioxidant agent in the future. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle High Molecular Weight Glucan of the Culinary Medicinal Mushroom Agaricus bisporus is an α-Glucan that Forms Complexes with Low Molecular Weight Galactan
Molecules 2010, 15(8), 5818-5830; doi:10.3390/molecules15085818
Received: 16 July 2010 / Revised: 20 August 2010 / Accepted: 24 August 2010 / Published: 25 August 2010
Cited by 13 | PDF Full-text (247 KB)
Abstract
An a-glucan was isolated from the culinary medicinal mushroom A. bisporus by hot water extraction, ethanol precipitation and DEAE-cellulose chromatography. The resulting material showed a single HMW peak excluded from a Sephadex G50 column that could completely be degraded by α-amylase treatment. After
[...] Read more.
An a-glucan was isolated from the culinary medicinal mushroom A. bisporus by hot water extraction, ethanol precipitation and DEAE-cellulose chromatography. The resulting material showed a single HMW peak excluded from a Sephadex G50 column that could completely be degraded by α-amylase treatment. After heating in 1% SDS a small additional peak of low MW eluted from the G50 column. The monosaccharide composition of the main peak was evaluated by HPLC, and was found to consist of a majority of glucose (97.6%), and a minor proportion of galactose (2.4%). Methylation analysis and degradation by a-amylase indicated the presence of an a-glucan with a main chain consisting of (1®4)-linked units, substituted at O-6 by α-D-glucopyranose single-units in the relation 1:8. Mono- (13C-, 1H-NMR) and bidimensional [1H (obs.),13C-HSQC] spectroscopy analysis confirmed the a-configuration of the Glcp residues by low frequency resonances of C-1 at d 100.6, 100.2, and 98.8 ppm and H-1 high field ones at d 5.06, 5.11, and 4.74 ppm. The DEPT-13C-NMR allowed assigning the non-substituted and O-substituted –CH2 signals at d 60.3/60.8 and 66.2 ppm, respectively. Other assignments were attributed to C-2, C-3, C-4, C-5 and C-6 of the non-reducing ends at d 71.8; 72.8; 70.0; 71.3 and 60.3/60.8 ppm, respectively. The minor proportion of galactose that was demonstrated was probably derived from a complex between the a-glucan and a low molecular weight galactan. Full article
Open AccessArticle Chemical Composition and Toxicity against Sitophilus zeamais and Tribolium castaneum of the Essential Oil of Murraya exotica Aerial Parts
Molecules 2010, 15(8), 5831-5839; doi:10.3390/molecules15085831
Received: 10 June 2010 / Revised: 17 August 2010 / Accepted: 19 August 2010 / Published: 25 August 2010
Cited by 53 | PDF Full-text (123 KB)
Abstract
In our screening program for new agrochemicals from Chinese medicinal herbs, Murraya exotica was found to possess insecticidal activity against the maize weevil, Sitophilus zeamais and red flour beetle, Tribolium castaneum. The essential oil of aerial parts of M. exotica was obtained
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In our screening program for new agrochemicals from Chinese medicinal herbs, Murraya exotica was found to possess insecticidal activity against the maize weevil, Sitophilus zeamais and red flour beetle, Tribolium castaneum. The essential oil of aerial parts of M. exotica was obtained by hydrodistillation and investigated by GC and GC-MS. The main components of M. exotica essential oil were spathulenol (17.7%), a-pinene (13.3%), caryophyllene oxide (8.6%), and a-caryophyllene (7.3%). Essential oil of M. exotica possessed fumigant toxicity against S. zeamais and T. castaneum adults with LC50 values of 8.29 and 6.84 mg/L, respectively. The essential oils also show contact toxicity against S. zeamais and T. castaneum adults with LD50 values of 11.41 and 20.94 mg/adult, respectively. Full article

Review

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Open AccessReview Chemistry of Nitroquinolones and Synthetic Application to Unnatural 1-Methyl-2-quinolone Derivatives
Molecules 2010, 15(8), 5174-5195; doi:10.3390/molecules15085174
Received: 14 July 2010 / Revised: 28 July 2010 / Accepted: 30 July 2010 / Published: 30 July 2010
Cited by 7 | PDF Full-text (1784 KB)
Abstract
The 1-methyl-2-quinolone (MeQone) framework is often found in alkaloids and recently attention was drawn to unnatural MeQone derivatives with the aim of finding new biologically active compounds, however, low reactivity of the MeQone framework prevents the syntheses of versatile derivatives. A nitro group is one
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The 1-methyl-2-quinolone (MeQone) framework is often found in alkaloids and recently attention was drawn to unnatural MeQone derivatives with the aim of finding new biologically active compounds, however, low reactivity of the MeQone framework prevents the syntheses of versatile derivatives. A nitro group is one of the useful activating groups for this framework that enables a concise chemical transformation. Among nitroquinolones, 1-methyl-3,6,8-trinitro-2-quinolone (TNQ) exhibits unusual reactivity favoring region-selective cine-substitutions that afford 4-substituted 1-methyl-6,8-dinitro-2-quinolones upon treatment with nucleophilic reagents. Contrary to this, 1-methyl-3,6-dinitro-2-quinolone (3,6-DNQ) does not undergo any reaction under the same conditions. The unusual reactivity of TNQ is caused by steric repulsion between the methyl group at the 1-position and the nitro group at the 8-position, which distorts the MeQone framework. As a result, the pyridone ring of TNQ loses aromaticity and acts rather as an activated nitroalkene. Indeed, the pyridone moiety of TNQ undergoes cycloaddition with electron-rich alkenes or dienes under mild conditions, whereby a new fused ring is constructed on the [c]-face of the MeQone. Consequently, TNQ can be used as a new scaffold leading to versatile unnatural MeQone derivatives. Full article
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
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Open AccessReview Photochemistry of Flavonoids
Molecules 2010, 15(8), 5196-5245; doi:10.3390/molecules15085196
Received: 19 May 2010 / Revised: 15 July 2010 / Accepted: 29 July 2010 / Published: 2 August 2010
Cited by 34 | PDF Full-text (461 KB)
Abstract
Flavonoids and their photochemical transformations play an important role in biological processes in nature. Synthetic photochemistry allows access to molecules that cannot be obtained via more conventional methods. This review covers all published synthetic photochemical transformations of the different classes of flavonoids. It
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Flavonoids and their photochemical transformations play an important role in biological processes in nature. Synthetic photochemistry allows access to molecules that cannot be obtained via more conventional methods. This review covers all published synthetic photochemical transformations of the different classes of flavonoids. It is first comprehensive review on the photochemistry of flavonoids. Full article
(This article belongs to the Special Issue Photochemistry in Organic Synthesis)
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Open AccessReview Solid-Phase Synthesis of N-Substituted Glycine Oligomers (α‑Peptoids) and Derivatives
Molecules 2010, 15(8), 5282-5335; doi:10.3390/molecules15085282
Received: 4 June 2010 / Revised: 14 July 2010 / Accepted: 2 August 2010 / Published: 4 August 2010
Cited by 68 | PDF Full-text (437 KB) | Supplementary Files
Abstract
Peptoids (N-substituted polyglycines and extended peptoids with variant backbone amino-acid monomer units) are oligomeric synthetic polymers that are becoming a valuable molecular tool in the biosciences. Of particular interest are their applications to the exploration of peptoid secondary structures and drug
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Peptoids (N-substituted polyglycines and extended peptoids with variant backbone amino-acid monomer units) are oligomeric synthetic polymers that are becoming a valuable molecular tool in the biosciences. Of particular interest are their applications to the exploration of peptoid secondary structures and drug design. Major advantages of peptoids as research and pharmaceutical tools include the ease and economy of synthesis, highly variable backbone and side-chain chemistry possibilities. At the same time, peptoids have been demonstrated as highly active in biological systems while resistant to proteolytic decay. This review with 227 references considers the solid-phase synthetic aspects of peptoid preparation and utilization up to 2010 from the instigation, by R. N. Zuckermann et al., of peptoid chemistry in 1992. Full article
(This article belongs to the Special Issue Solid Phase Synthesis)
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Open AccessReview Hammerhead Ribozymes: True Metal or Nucleobase Catalysis? Where Is the Catalytic Power from?
Molecules 2010, 15(8), 5389-5407; doi:10.3390/molecules15085389
Received: 1 June 2010 / Revised: 29 July 2010 / Accepted: 4 August 2010 / Published: 6 August 2010
Cited by 10 | PDF Full-text (591 KB)
Abstract
The hammerhead ribozyme was first considered as a metalloenzyme despite persistent inconsistencies between structural and functional data. In the last decade, metal ions were confirmed as catalysts in self-splicing ribozymes but displaced by nucleobases in self-cleaving ribozymes. However, a model of catalysis just
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The hammerhead ribozyme was first considered as a metalloenzyme despite persistent inconsistencies between structural and functional data. In the last decade, metal ions were confirmed as catalysts in self-splicing ribozymes but displaced by nucleobases in self-cleaving ribozymes. However, a model of catalysis just relying on nucleobases as catalysts does not fully fit some recent data. Gathering and comparing data on metal ions in self-cleaving and self-splicing ribozymes, the roles of divalent metal ions and nucleobases are revisited. Hypothetical models based on cooperation between metal ions and nucleobases are proposed for the catalysis and evolution of this prototype in RNA catalysis. Full article
(This article belongs to the Special Issue Catalytic Nucleic Acids)
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Open AccessReview Molecular Evolution of Functional Nucleic Acids with Chemical Modifications
Molecules 2010, 15(8), 5423-5444; doi:10.3390/molecules15085423
Received: 18 June 2010 / Revised: 14 July 2010 / Accepted: 6 August 2010 / Published: 9 August 2010
Cited by 49 | PDF Full-text (856 KB)
Abstract
Nucleic acids are attractive materials for creating functional molecules that have applications as catalysts, specific binders, and molecular switches. Nucleic acids having such functions can be obtained by random screening, typically using in vitro selection methods. These methods have helped explore the potential
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Nucleic acids are attractive materials for creating functional molecules that have applications as catalysts, specific binders, and molecular switches. Nucleic acids having such functions can be obtained by random screening, typically using in vitro selection methods. These methods have helped explore the potential abilities of nucleic acids and steadily contributed to their evolution, i.e., creation of RNA/DNA enzymes, aptamers, and aptazymes. Chemical modification would be a key means to further increase their performance, e.g., expansion of function diversity, enhancement of activity, and improvement of biostability for biological use. Indeed, in the past two decades, random screening involving chemical modification, post-SELEX chemical modification, and rational design methods have been advanced, and combining and integrating these methods may produce a new class of functional nucleic acids. This review focuses on the effectiveness of chemical modifications on the evolution of nucleic acids as functional molecules and the outlook for related technologies. Full article
(This article belongs to the Special Issue Catalytic Nucleic Acids)
Open AccessReview The Application of Ribozymes and DNAzymes in Muscle and Brain
Molecules 2010, 15(8), 5460-5472; doi:10.3390/molecules15085460
Received: 18 June 2010 / Revised: 3 August 2010 / Accepted: 5 August 2010 / Published: 9 August 2010
Cited by 7 | PDF Full-text (113 KB)
Abstract
The discovery of catalytic nucleic acids (CNAs) has provided scientists with valuable tools for the identification of new therapies for several untreated diseases through down regulation or modulation of endogenous gene expression involved in these ailments. These CNAs aim either towards the elimination
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The discovery of catalytic nucleic acids (CNAs) has provided scientists with valuable tools for the identification of new therapies for several untreated diseases through down regulation or modulation of endogenous gene expression involved in these ailments. These CNAs aim either towards the elimination or repair of pathological gene expression. Ribozymes, a class of CNAs, can be mostly used to down-regulate (by RNA cleavage) or repair (by RNA trans-splicing) unwanted gene expression involved in disease. DNAzymes, derived by in vitro selection processes are also able to bind and cleave RNA targets and therefore down-regulate gene expression. The purpose of this review is to present and discuss several applications of ribozymes and DNAzymes in muscle and brain. There are several diseases which affect muscle and brain and catalytic nucleic acids have been used as tools to target specific cellular transcripts involved in these groups of diseases. Full article
(This article belongs to the Special Issue Catalytic Nucleic Acids)
Open AccessReview Preparation of Tyrian Purple (6,6′-Dibromoindigo): Past and Present
Molecules 2010, 15(8), 5473-5508; doi:10.3390/molecules15085473
Received: 18 June 2010 / Revised: 29 July 2010 / Accepted: 2 August 2010 / Published: 10 August 2010
Cited by 8 | PDF Full-text (302 KB)
Abstract Over the past century, various synthetic approaches have been suggested to the most famous dye of antiquity, Tyrian purple (6,6′-dibromoindigo). These synthetic routes have been exhaustively surveyed and critically evaluated from the perspective of convenience, cost, safety and yield. Full article
Open AccessReview Nanofabrication of Nonfouling Surfaces for Micropatterning of Cell and Microtissue
Molecules 2010, 15(8), 5525-5546; doi:10.3390/molecules15085525
Received: 11 June 2010 / Revised: 20 July 2010 / Accepted: 4 August 2010 / Published: 10 August 2010
Cited by 19 | PDF Full-text (846 KB)
Abstract
Surface engineering techniques for cellular micropatterning are emerging as important tools to clarify the effects of the microenvironment on cellular behavior, as cells usually integrate and respond the microscale environment, such as chemical and mechanical properties of the surrounding fluid and extracellular matrix,
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Surface engineering techniques for cellular micropatterning are emerging as important tools to clarify the effects of the microenvironment on cellular behavior, as cells usually integrate and respond the microscale environment, such as chemical and mechanical properties of the surrounding fluid and extracellular matrix, soluble protein factors, small signal molecules, and contacts with neighboring cells. Furthermore, recent progress in cellular micropatterning has contributed to the development of cell-based biosensors for the functional characterization and detection of drugs, pathogens, toxicants, and odorants. In this regards, the ability to control shape and spreading of attached cells and cell-cell contacts through the form and dimension of the cell-adhesive patches with high precision is important. Commitment of stem cells to different specific lineages depends strongly on cell shape, implying that controlled microenvironments through engineered surfaces may not only be a valuable approach towards fundamental cell-biological studies, but also of great importance for the design of cell culture substrates for tissue engineering. To develop this kind of cellular microarray composed of a cell-resistant surface and cell attachment region, micropatterning a protein-repellent surface is important because cellular adhesion and proliferation are regulated by protein adsorption. The focus of this review is on the surface engineering aspects of biologically motivated micropatterning of two-dimensional surfaces with the aim to provide an introductory overview described in the literature. In particular, the importance of non-fouling surface chemistries is discussed. Full article
(This article belongs to the Special Issue High-throughput Screening)
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Open AccessReview Emerging Biological Importance of Central Nervous System Lanthionines
Molecules 2010, 15(8), 5581-5594; doi:10.3390/molecules15085581
Received: 27 July 2010 / Revised: 10 August 2010 / Accepted: 12 August 2010 / Published: 13 August 2010
Cited by 28 | PDF Full-text (166 KB)
Abstract
Lanthionine (Lan), the thioether analog of cystine, is a natural but nonproteogenic amino acid thought to form naturally in mammals through promiscuous reactivity of the transsulfuration enzyme cystathionine-b-synthase (CbS). Lanthionine exists at appreciable concentrations in mammalian brain, where it undergoes aminotransferase conversion to
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Lanthionine (Lan), the thioether analog of cystine, is a natural but nonproteogenic amino acid thought to form naturally in mammals through promiscuous reactivity of the transsulfuration enzyme cystathionine-b-synthase (CbS). Lanthionine exists at appreciable concentrations in mammalian brain, where it undergoes aminotransferase conversion to yield an unusual cyclic thioether, lanthionine ketimine (LK; 2H-1,4-thiazine-5,6-dihydro-3,5-dicarboxylic acid). Recently, LK was discovered to possess neuroprotective, neuritigenic and anti-inflammatory activities. Moreover, both LK and the ubiquitous redox regulator glutathione (g-glutamyl-cysteine-glycine) bind to mammalian lanthionine synthetase-like protein-1 (LanCL1) protein which, along with its homolog LanCL2, has been associated with important physiological processes including signal transduction and insulin sensitization. These findings begin to suggest that Lan and its downstream metabolites may be physiologically important substances rather than mere metabolic waste. This review summarizes the current state of knowledge about lanthionyl metabolites with emphasis on their possible relationships to LanCL1/2 proteins and glutathione. The potential significance of lanthionines in paracrine signaling is discussed with reference to opportunities for utilizing bioavailable pro-drug derivatives of these compounds as novel pharmacophores. Full article
(This article belongs to the Special Issue Neuroactive Compounds)
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Open AccessReview Click Reactions and Boronic Acids: Applications, Issues, and Potential Solutions
Molecules 2010, 15(8), 5768-5781; doi:10.3390/molecules15085768
Received: 30 June 2010 / Revised: 27 July 2010 / Accepted: 4 August 2010 / Published: 23 August 2010
Cited by 22 | PDF Full-text (156 KB)
Abstract
Boronic acids have been widely used in a wide range of organic reactions, in the preparation of sensors for carbohydrates, and as potential pharmaceutical agents. With the growing importance of click reactions, inevitably they are also applied to the synthesis of compounds containing
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Boronic acids have been widely used in a wide range of organic reactions, in the preparation of sensors for carbohydrates, and as potential pharmaceutical agents. With the growing importance of click reactions, inevitably they are also applied to the synthesis of compounds containing the boronic acid moiety. However, such applications have unique problems. Chief among them is the issue of copper-mediated boronic acid degradation in copper-assisted [2,3]-cycloadditions involving an alkyne and an azido compound as the starting materials. This review summarizes recent developments, analyzes potential issues, and discusses known as well as possible solutions. Full article
(This article belongs to the Special Issue Click Chemistry)

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