- Anti‐melanogenic properties of velutin and its analogs?
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Velutin, one of the flavones contained in natural plants, has various beneficial activities, such as skin whitening, as well as anti‐inflammatory, anti‐allergic, antioxidant, and antimicrobial activities. However, the relationship between the structure of velutin and its anti‐melanogenesis activity is not yet investigated. In this study, we obtained 12 velutin derivatives substituted at C5, C7, C3′, and C4′ of the flavone backbone with hydrogen, hydroxyl, and methoxy functionalities by chemical synthesis, to perform SAR analysis of velutin structural analogues. The SAR study revealed that the substitution of functional groups at C5, C7, C3′, and C4′ of the flavone backbone affects biological activities related to melanin synthesis. The coexistence of hydroxyl and methoxy at the C5 and C7 position is essential for inhibiting tyrosinase activity. However, 1,2‐diol compounds substituted at C3′ and C4′ of flavone backbone induce apoptosis of melanoma cells. Further, substitution at C3′ and C4′ with methoxy or hydrogen is essential for inhibiting melanogenesis. Thus, this study would be helpful for the development of natural‐derived functional materials to regulate melanin synthesis.
- Choe, Jung-Won,Heo, Hee-Young,Jung, Se-Hui,Kim, Jaehyun,Lee, Kooyeon
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- Process for preparing flavonoid derivatives and the intermediate thereof
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The present invention provides: a method for manufacturing a flavonoid derivative using a reaction for synthesizing a chalcone derivative by a protection/deprotection reaction of a hydroxyl group and an aldol condensation reaction; and an intermediate thereof. By the method for manufacturing the flavonoid derivative of the present invention can manufacture the flavonoid derivative such as velutin and homoeriodictyol, the present invention can be usefully used in industrial fields such as cosmetics requiring mass production of flavonoid derivatives.
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- Acidic rearrangement of benzyl group in flavone benzyl ethers and its regioselectivity
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Abstract The benzyl-substituted flavone compounds are rare in nature, while some of which have interesting biological activities. The total synthesis of benzyl-substituted flavone derivatives via the acidic rearrangement of benzyl groups in flavone benzyl ethers, and the complicated regioselectivity of the rearrangement were reported. The regioselectivity was proposed to be determined by the steric hindrance as well as the ease of electrophilic substitution reaction for benzyl cations at different positions of corresponding debenzylated flavone compounds.
- Wang, Chong-Qing,Chen, Xin,Jiang, Jun-Hang,Tang, Hui,Zhu, Kong-Kai,Zhou, You-Jun,Zheng, Can-Hui,Zhu, Ju
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supporting information
p. 793 - 796
(2015/08/03)
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- New chemical constituents from oryza sativa straw and their algicidal activities against blue-green algae
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Five new constituents, 5,4′-dihydroxy-7,3′-dimethoxyflavone- 4′-O-β-d-xylopyranosyl-(2a→1b)-2a-O-β-d-xylopyranosyl- (2b→1c)-2b-O-β-d-xylopyranosyl-2c-octadecanoate (1), 5,4′-dihydroxy-7,3′-dimethoxyflavone-4′-O-α-d- xylopyranosyl-(2a→1b)-2a-O-α-d-xylopyranosyl-(2b→1c) -2b-O-α-d-xylopyranosyl-(2c→1d)-2c-O-α-d-xylopyranosyl-2d- octadecanoate (2), kaempferol-3-O-α-d-xylopyranosyl-(2a→1b)-2a-O- α-d-xylopyranosyl-(2b→1c)-2b-O-α-d-xylopyranosyl-(2c→1d) -2c-O-α-d-xylopyranosyl-2d-hexadecanoate (3), methyl salicylate-2-O- α-d-xylopyranosyl-(2a→1b)-2a-O-α-d-xylopyranosyl-(2b→1c) -2b-O-α-d-xylopyranosyl-(2c→1d)-2c-O-α-d-xylopyranosyl- (2d→1e)-2d-O-α-d-xylopyranosyl-(2e→1f)-2e-O-α-d- xylopyranosyl-(2f→1g)-2f-O-α-d-xylopyranosyl-(2g→1h) -2g-O-α-d-xylopyranosyl-2h-geranilan-8′,10′-dioic acid-1′-oate (4), and oleioyl-β-d-arabinoside (5), along with eight known compounds, were isolated from a methanol extract of Oryza sativa straw. The structures of the new compounds were elucidated using one- and two-dimensional NMR spectroscopies in combination with IR, ESI/MS, and HR-ESI/FTMS. In bioassays with blue-green algae, the efficacies of the algicidal activities of the five new compounds (1-5) were evaluated at concentrations of 1, 10, and 100 mg/L. Compound 5 had the highest growth inhibition (92.6 ± 0.3%) for Microcystis aeruginosa UTEX 2388 at a concentration of 100 ppm (mg/L). Compound 5 has high potential for the ecofriendly control of weeds and algae harmful to water-logged rice.
- Ahmad, Ateeque,Kim, Seung-Hyun,Ali, Mohd,Park, Inmyoung,Kim, Jin-Seog,Kim, Eun-Hye,Lim, Ju-Jin,Kim, Seul-Ki,Chung, Ill-Min
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p. 8039 - 8048
(2013/09/23)
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- On a Thermal Transmethylation Reaction with Flavon-5-methylethers
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Upon heating to 300 deg C partial luteolinemethylethers undergo transmethylation.A reaction mechanism is put foreward. - Key words: Flavonemethylethers, Thermal Transmethylation, TLC, HPLC, Reaction Mechanism
- Geiger, Hans,Casteele, Karel Vande,Sumere, Christiaan F. Van
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p. 393 - 396
(2007/10/02)
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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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