- A Versatile Microbial System for Biosynthesis of Novel Polyphenols with Altered Estrogen Receptor Binding Activity
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Isoflavonoids possess enormous potential for human health with potential impact on heart disease and cancer, and some display striking affinities for steroid receptors. Synthesized primarily by legumes, isoflavonoids are present in low and variable abundance within complex mixtures, complicating efforts to assess their clinical potential. To satisfy the need for controlled, efficient, and flexible biosynthesis of isoflavonoids, a three-enzyme system has been constructed in yeast that can convert natural and synthetic flavanones into their corresponding isoflavones in practical quantities. Based on the determination of the substrate requirements of isoflavone synthase, a series of natural and nonnatural isoflavones were prepared and their binding affinities for the human estrogen receptors (ERα and ERβ) were determined. Structure activity relationships are suggested based on changes to binding affinities related to small variations on the isoflavone structure.
- Chemler, Joseph A.,Lim, Chin Giaw,Daiss, John L.,Koffas, Mattheos A.G.
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experimental part
p. 392 - 401
(2011/06/28)
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- Synthesis of various kinds of isoflavones, isoflavanes, and biphenyl- ketones and their 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activities
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Forty-eight kinds of isoflavones (8), thirty-one isoflavanes (9), and forty-seven biphenyl-ketones (10, 10') were synthesized from eleven kinds of substituted phenols (11) and six phenylacetic acids (12). Among them, seventy-five compounds are new. The radical scavenging activities of these compounds were evaluated using 1,1- diphenyl-2-picrylhydrazyl (DPPH) at pH 6.0. We found that thirty-nine out of forty-three compounds having a catechol moiety on either the A- or the B-ring exhibited a high activity (ED50=12-54 μM) similar to that of catechin. In these cases, the remaining part of their structure seemed to have little effect on their activity. Many 6- or 8-hydroxyisoflavanes (9E-I) and their biphenyl-ketone derivatives (10E-H) also showed a high activity (ED50=50=26-32 μM). This study suggests that natural isoflavones have the possibilities of exhibiting antioxidant activities through the hydroxylation at the C6-, C8-, or C3'-position or the formation of the isoflavanes (9) and/or the biphenyl-ketone derivatives (10') by metabolism or biotransformation.
- Goto, Hideyuki,Terao, Yoshiyasu,Akai, Shuji
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experimental part
p. 346 - 360
(2009/12/27)
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- Phenolic glucosides from the root of Pueraria lobata
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Six phenolic glucosides were isolated from the methanolic extract of the root of Pueraria lobata. Three of them were new compounds and their structures were proved to be kuzubutenolide A, 3'-hydroxy-4'-O-β-D- glucosylpuerarin and 3'-methoxydaidzin.
- Hirakura, Kazuhiro,Morita, Makoto,Nakajima, Kaoru,Sugama, Koh,Takagi, Koji,Niitsu, Kazuaki,Ikeya, Yukinobu,Maruno, Masao,Okada, Minoru
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p. 921 - 928
(2007/10/03)
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- Expedient Synthesis of Polyhydroxyisoflavones
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A general and direct synthesis of polyhydroxy isoflavones (3-phenyl-4H-1-benzopyran-4-ones) starting from the corresponding unprotected phenols and arylacetic acids is described.The aryl rings may carry additional alkyl, methoxy and/or halogeno groups.Intermediate polyhydroxydeoxybenzoins (1,2-diphenylethanones) can also be isolated in good yields.
- Waehaelae, Kristiina,Hase, Tapio A.
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p. 3005 - 3008
(2007/10/02)
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