- Natural and Synthetic Flavonoids as Potent Mycobacterium tuberculosis UGM Inhibitors
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This study reports a novel class of inhibitors of uridine 5′-diphosphate (UDP) galactopyranose mutase (UGM) derived from a screening of natural products. This enzyme is an essential biocatalyst involved in the cell wall biosynthesis of Mycobacterium tuberculosis. Flavonoids are potent inhibitors of UGM. The synthesis of novel methylated flavonoids allowed a structure–activity relationship analysis to be performed and which functional groups and structural elements were required for UGM inhibition could be determined. The binding mode of one of the best inhibitors was found to be noncompetitive. Docking simulations indicated that this molecule was likely to bind UGM in its open conformation, in a cavity recently identified as a “druggable” pocket. Importantly, two of the best inhibitors of the M. tuberculosis UGM displayed moderate activity against whole M. tuberculosis cells. This study reports the first natural products that act as inhibitor of UGM. Given the importance of natural products in medicinal chemistry, these results create new opportunities for the discovery of new antitubercular agents.
- Villaume, Sydney A.,Fu, Jian,N'Go, Inès,Liang, Hui,Lou, Huayong,Kremer, Laurent,Pan, Weidong,Vincent, Stéphane P.
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supporting information
p. 10423 - 10429
(2017/08/07)
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- Effects of Functional Groups and Sugar Composition of Quercetin Derivatives on Their Radical Scavenging Properties
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Quercetin derivatives are widespread in the plant kingdom and exhibit various biological actions. The aim of this study was to investigate the structure-activity relationships of quercetin derivatives, with a focus on the influence of functional groups and sugar composition on their antioxidant capacity. A series of quercetin derivatives were therefore prepared and assessed for their DPPH radical scavenging properties. Isoquercetin O-gallates were more potent radical scavengers than quercetin. The systematic analysis highlights the importance of the distribution of hydroxy substituents in isoquercetin O-gallates to their potency.
- Kato, Komei,Ninomiya, Masayuki,Tanaka, Kaori,Koketsu, Mamoru
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supporting information
p. 1808 - 1814
(2016/08/02)
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- Flavonoids of carthamus tinctorius flowers
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The known flavonoids luteolin, cinaroside, 5-O-methylluteolin, azaleatin (3,7,3′,4′-tetrahydroxy-5-methoxyflavone), and the new natural product 3,7,3′,4′-tetrahydroxy-5-methoxyflavone 7-O-β- Dglucopyranoside (safloroside) were isolated from Carthamus tinctorius flowers and characterized by PMR and UV spectroscopy and mass spectrometry.
- Kurkin,Kharisova
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p. 446 - 448
(2014/08/18)
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- Biological evaluation and SAR analysis of O-methylated analogs of quercetin as inhibitors of cancer cell proliferation
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Preclinical Research Using a high-throughout screening approach, the anticancer activities of 16 O-methylated (OMe) analogs of quercetin were assessed. The structure-activity relationships showed that OMe moieties at the 4′ and/or 7 positions were important for maintaining inhibitory activities against the 16 cancer cell lines. Furthermore, when the OH groups at the 3′ and 4′ positions were both replaced by OMe moieties, anticancer activity was enhanced.
- Shi, Zhi-Hao,Li, Nian-Guang,Tang, Yu-Ping,Shi, Qian-Ping,Tang, Hao,Li, Wei,Zhang, Xu,Fu, Hai-An,Duan, Jin-Ao
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p. 455 - 462
(2015/04/14)
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- Metabolism-based synthesis, biologic evaluation and SARs analysis of O-methylated analogs of quercetin as thrombin inhibitors
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In blood, quercetin is mainly found in metabolized forms. In order to study the activities of these quercetin metabolites in cardiovascular disease, 17 methylquercetin derivatives were synthesized based on metabolism in vivo, their thrombin inhibition activity were evaluated through the analyzation of prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen (FIB). The results showed that 6 methylquercetin derivatives had stronger inhibitory activities than that of quercetin. Preliminary SARs analysis showed that hydroxyl groups at C-3′ and C-4′ position in the B-ring and hydroxyl group at C-3 position in the C-ring played key roles in the thrombin inhibitory activity. The findings of this study would provide information for the exploitation and utilization of quercetin as thrombin inhibitor for thrombotic disease treatment.
- Shi, Zhi-Hao,Li, Nian-Guang,Tang, Yu-Ping,Wei-Li,Lian-Yin,Yang, Jian-Ping,Hao-Tang,Duan, Jin-Ao
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p. 210 - 222
(2012/09/07)
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- Selective monomethylation of quercetin
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Quercetin was monomethylated under mild conditions in moderate yields through selective deprotection. The combined effects of the protecting group and the heating mode on the reactivity were investigated. The presence of borax and the use of microwave irradiation significantly improved the yield and selectivity of alkylation. Georg Thieme Verlag Stuttgart - New York.
- Zhou, Zhong-Hua,Fang, Zhuan,Jin, Hui,Chen, Yue,He, Ling
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experimental part
p. 3980 - 3986
(2011/02/22)
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- Hemisynthesis of all the O-monomethylated analogues of quercetin including the major metabolites, through selective protection of phenolic functions
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A new methodology for the hemisynthesis of all the five O-monomethylated analogues of quercetin (3′-O-methylquercetin (isorhamnetin), 4′-O-methylquercetin (tamarixetin), 3-O-methylquercetin, 5-O-methylquercetin (azaleatin) and 7-O-methylquercetin (rhamnetin)) through sequential protection of the different phenolic functions of quercetin is reported.
- Bouktaib, Mohamed,Lebrun, Stéphane,Atmani, Aziz,Rolando, Christian
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p. 10001 - 10009
(2007/10/03)
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- O-methylation of flavonoids by cell-free extracts of calamondin orange
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Cell-free extracts of calamondin orange (Citrus mitis) catalysed the O-methylation of almost all hydroxyls of a number of flavonoids, indicating the existence in citrus tissues of ortho, meta, para and 3-O-methyltransferases. The latter, hitherto unreported enzyme, catalysed the formation of 3-O-methyl ethers of galangin and quercetin. The stepwise O-methylation of a number of compounds, especially quercetin and quercetagetin, tends to suggest a coordinated sequence of O-methylations on the surface of a multienzyme complex. The methyl acceptor abilities of the flavonoid substrates used are discussed in relation to their hydroxyl substitution patterns and their negative electron density distribution.
- Brunet, Gunter,Ibrahim, Ragai K.
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p. 741 - 746
(2007/10/02)
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