- Quercetin analogs with high fetal hemoglobin-inducing activity
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β-Thalassemia is the major health problems in developing countries, when affected patients and healthy carriers are numerous, resulting a total absence or severe decrease in the production of β-globin chains. The use of chemical agents for increasing the production of fetal hemoglobin (HbF) by reactivating γ-globin gene to balance excess α-globin chains is an alternative therapeutic approach. Therefore, the search for molecules exhibiting the property of inducing γ-globin gene expression is of great interest. In this report, we discovered that quercetin (1), the major flavonoid isolated from the heartwoods of the medicinal plant Anaxagorea luzonensis promoted the expression of γ-globin gene. Chemical modification of 1 to fourteen methyl ether analogs (2?15) was conducted. The structures of these compounds were established on the basis of their spectroscopic data and by comparison with those of the reported values. The parent flavonoid and its chemically modified analogs were investigated for their γ-globin gene induction for the first time. The parent compound 1 exhibited less induced γ-globin gene expression than cisplatin and hemin, the positive controls. 3,4′-Di-O-methylquercetin (7), the modified analog, significantly enhanced γ-globin gene expression with 2.6-fold change at 8 μM, which was slightly higher than cisplatin and hemin. Moreover, compounds 1 and 7 displayed less cytotoxic activity against K562::ΔGγAγEGFP cells than cisplatin. Structure-activity relationship (SAR) study revealed that the methoxyl groups at the 3- and 4?-positions and the free hydroxyl group at the 7-position are required for strong HbF-inducing activity.
- Pabuprapap, Wachirachai,Wassanatip, Yanisa,Khetkam, Pichit,Chaichompoo, Waraluck,Kunkaewom, Sukanya,Senabud, Pongpan,Hata, Janejira,Chokchaisiri, Ratchanaporn,Svasti, Saovaros,Suksamrarn, Apichart
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p. 1755 - 1765
(2019/08/02)
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- Quercetin derivative and its preparation method and application
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The invention discloses a quercetin derivative and a preparation method and application thereof. The preparation method comprises the following steps: firstly using dichlorodiphenylmethane to protect quercetin o-diphenol hydroxyl, combining a benzyl protection group to obtain the selectively protected quercetin derivative, and then independently reacting with dimethyl sulfate, diethyl sulfate, allyl bromide, paratoluensulfonyl chloride and acetic anhydride respectively to generate corresponding quercetin derivatives. All of the prepared derivative compounds have NRK-49F proliferation activity inhibition superior to that of quercetin. The quercetin derivatives 20a-1, 14a-1 and 23d-1 compositely replaced by methyl and p-tosyl have higher inhibition NRK-49F proliferation activity, and the inhibition ratio respectively reaches 86.33%, 78.04% and 75.91%. Thus, the currently obtained quercetin derivative compounds have obvious inhibition effect on kidney fibroblast NRK-49F proliferation.
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Paragraph 0078
(2018/01/19)
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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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experimental part
p. 210 - 222
(2012/09/07)
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- Chemical constituents from cassia occidentalis Linn
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The present paper deals with the isolation and structural elucidation of three new compounds 1, 2 and 3 from the seeds of Cassia occidentalis Linn. These compounds have been characterized as 5, 7-dihydroxyflavone-5-O-β-D- xylopyranosyl-7-O-α-L-rhamnopyranosyl-(1→3)-O-α-L- arabinopyranoside (1), 3, 5, 7, 3′,4′-pentahydroxy flavone-3-O-α-L-rhamnopyranosyl-7-O-β-D-glucopyranosyl-(1→3) -O-β-D-xylopyranoside (2) and 5, 7, 3′, 4′-tetrahydroxy-6- methoxyflavone-5-O-α-L-ara-binopyranosyl-(1→4)-O-α-L- rhamnopyranosyl-(1→3)-O-β-D-galactopyranoside (3) respectively by various colour reactions, chemical degradations and spectral analysis. These compounds have been evaluated against various bacteria and fungi which showed good results.
- Yadava,Satnami
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experimental part
p. 1112 - 1118
(2011/10/09)
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