Publications by authors named "Mohsen Daneshtalab"

Various species of berries have been reported to contain several polyphenolic compounds, such as anthocyanins and flavonols, which are known to possess high antioxidant activity and may be beneficial for human health. To our knowledge, a thorough chemical analysis of polyphenolics in species of these plants native to Newfoundland, Canada has not been conducted. The primary objective of this study was to determine the polyphenolic compounds present in commercial extracts from Newfoundland berries, which included blueberries (), lingonberries () and black currant ().

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Chlorogenic acid is a well known natural product with important bioactivities. It contains an ester bond formed between the COOH of caffeic acid and the 3-OH of quinic acid. We synthesized a chlorogenic acid analogue, 3α-caffeoylquinic acid amide, using caffeic and quinic acids as starting materials.

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Quinolones are considered as a big family of multi-faceted drugs; their chemical synthesis is flexible and can be easily adapted to prepare new congeners with rationally devised structures. This is shown by the description of many thousands of derivatives in the literature. Scientists could accurately describe their QSAR, which is essential for effective drug design.

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In the title mol-ecule, C(16)H(9)NO(5)S, there is an intra-molecular O-H⋯O hydrogen bond involving the quinolone carbonyl O atom and a carboxyl OH group. In the crystal, inter-molecular O-H⋯O hydrogen bonds between the carbonyl group of the quinolone carboxyl group, and a second carboxyl group on the thia-zeto moiety lead to the formation of chains propagating along [201] and perpendicular to the π-stacks of mol-ecules.

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New derivatives of caffeic acid and quinic acid were synthesized and their anti-fungal and inhibitory activities on fungal 1,3-β-glucan synthase were determined in comparison with those of the corresponding chlorogenic acid derivatives. All the chlorogenic, quinic and caffeic acid derivatives that were coupled with an H(2)N-orn-4-(octyloxy) aniline group (1, 1b and 1c) displayed potent activities in both anti-fungal and inhibition of 1,3-glucan synthase assays. Compounds 1 and 1c inhibited the fungal membrane enzyme with the potency comparable to that of a known 1,3-β-D-glucan synthase inhibitor, aculeacin A.

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In our continued research on chlorogenic acid analogues and derivatives with improved bioactivity, we have synthesized some caffeoyl 5,6-anhydroquinic acid derivatives. The 1,7 acetonides of chlorogenic acid (15), and of the mono-caffeoyl 5,6-anhydroquinic acids (7-8) showed appreciable anti-HIV activity. The 3,4-dicaffeoyl 5,6-anhydroquinic acid (12) exhibited an anti-HIV activity twice as that of 3,5-dicaffeoylquinic acid (22).

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Life-threatening fungal infections have increased dramatically in recent decades in immunocompromised patients. An estimated 40% of all deaths from hospital-acquired infections are due to infections caused by opportunistic fungi. The current treatment options are either causing serious toxicity, or becoming inactive against the drug-resistant fungal strains.

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Alpha-glucosidases play important roles in the digestion of carbohydrates and biosynthesis of viral envelope glycoproteins. Inhibitors of alpha-glucosidase are promising candidates for the development of antitype II diabetics and anti-AIDS drugs. Here, we report the synthesis and alpha-glucosidase inhibitory activity of mono- and diketal/acetal derivatives of chlorogenic acid.

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An HPLC-PAD-MS(n) method was employed to profile the phenolic compounds of the aerial part of Artemisia pectinata (Neopallasia pectinata), a plant with no previous reports concerning its phenolic constituents. Three isomers of trans-caffeoylquinic acid accompanied by cis-5-caffeoylquinic acid, six isomers of trans-dicaffeoylquinic acid, two isomers of methyl trans-dicaffeoylquinate (including one new isomer), a trans-caffeoylferuloylquinic acid and three flavanoids were identified unambiguously by analysis of their UV and MS(n) spectra in comparison with standard compounds that were isolated from natural sources, or synthesised, or were surrogate standards (green coffee extract). Other compounds were identified by analysis of their UV and MSn data in comparison with those reported in the literature.

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Derivatives of chlorogenic acid or its analogues were synthesized by coupling protected chlorogenic acid or its analogues with p-octyloxyaniline and selected amino acids. Most of the compounds exhibited significant potency against Cryptococcus neoformans and Candida species with low toxicity to brine shrimps. The 4,5-dihydroxyl groups in the quinic acid moiety were necessary for the activity and introduction of a free amino group increased the inhibitory activity against Aspergillus fumigatus.

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A simple HPLC-PAD-MS method was established to quantitatively analyse two spiroether isomers (cis-en-yn-dicycloether and trans-en-yn-dicycloether) and the main coumarin, herniarin, in chamomile herbs, simultaneously. By using this method, the contents of these three compounds in the flowers of two chamomile species, Roman chamomile (Chamaemelum nobile) and pineapple weed (Matricaria matricarioides), as well as in different parts of pineapple weed, were investigated. It was found that the flowers of both herbs contained large amounts of cis-en-yn-dicycloether and trans-en-yn-dicycloether, with the trans-form being more abundant than the cis-form.

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Azolylalkylquinolines (AAQs) are a family of quinolines with varying degrees of cytotoxic activity (comparable or moderately superior to adriamycin in some cases) developed in the past decade in our group where their exact mode of action is still unclear. In this study the most probable DNA binding mode of AAQs was investigated employing a novel flexible ligand docking approach by using AutoDock 3.0.

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Ursolic acid and 2alpha-hydroxyursolic acid isolated from apple peels were found to show growth inhibitory activity against four tumor cell lines, HL-60, BGC, Bel-7402 and Hela. Structural modifications were performed on the C-3, C-28 and C-11 positions of ursolic acid and the cytotoxicity of the derivatives was evaluated. The SAR revealed that the triterpenes possessing two hydrogen-bond forming groups (an H-donor and a carbonyl group) at positions 3 and 28 exhibit cytotoxic activity.

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Several new and known 2-(4-substituted phenyl)-3(2H)-isothiazolone derivatives with or without chloro substituent at C-5 position were synthesized and their in vitro antibacterial activity against selected Gram-negative and Gram-positive bacteria were evaluated using agar dilution method. Most of compounds exhibited moderate to high activities against tested microorganisms, and in comparison with the reference drugs some compounds showed comparable or higher activities. In contrast to results of the previous studies, some 5-chloro derivatives showed lower or comparable activities against some tested microorganism, in comparison with analogues without C-5 substitution.

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