- THE FIRST IDENTIFICATION OF ISOFLAVONES FROM A BRYOPHYTE
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Bryum capillare is shown to accumulate the isoflavones orobol and pratensein as the 7-O-glucosides and predominantly, as the 7-(6''-malonylglucosides).This is the first finding of isoflavonoids in bryophytes.The phylogenetic relevance of this observation is briefly discussed.Key Word Index - Bryum capillare; Bryales; Musci; moss; isoflavones; orobol; pratensein; 7-O-glucosides; 6''-malonyl glucosides; NMR spectra.
- Anhut, Siegbert,Zinsmeister, H. Dietmar,Mues, Ruediger,Barz, Wolfgang,Mackenbrock, Klaus,et al.
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- Production and anti-melanoma activity of methoxyisoflavones from the biotransformation of genistein by two recombinant Escherichia coli strains
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Biotransformation of the soy isoflavone genistein by sequential 3′-hydroxylation using recombinant Escherichia coli expressing tyrosinase from Bacillus megaterium and then methylation using another recombinant E. coli expressing O-methyltransferase from S
- Chiang, Chien-Min,Chang, Yu-Jhe,Wu, Jiumn-Yih,Chang, Te-Sheng
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- Inhibition of extrahepatic human cytochromes P450 1A1 and 1B1 by metabolism of isoflavones found in Trifolium pratense (red clover)
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Biochanin A and formononetin are the predominant isoflavones in red clover. In a previous study (J. Agric. Food Chem. 2002, 50, 4783-4790), it was demonstrated that human liver microsomes converted biochanin A and formononetin to genistein and daidzein. This paper now shows CYP1B1-catalyzed O-demethylation of biochanin A and formononetin to produce genistein and daidzein, respectively, which inhibit CYP1B1. Recombinant human CYP1A1 or CYP1B1 was incubated with biochanin A or formononetin. CYP1A1 catalyzed isoflavone 4′-O-demethylation and hydroxylations with similar efficiency, whereas CYP1B1 favored 4′-O-demethylation over hydroxylations. Three of the biochanin A metabolites (5,7,3′-trihydroxy-4′-methoxyisoflavone, 5,7,8-trihydroxy-4′-methoxyisoflavone, and 5,6,7-trihydroxy-4′- methoxyisoflavone) were characterized by 1H NMR spectroscopy and mass spectrometry. Daidzein (Ki = 3.7 μM) exhibited competitive inhibition of CYP1B1 7-ethoxyresorufin O-deethylase activity, and genistein (Ki = 1.9 μM) exhibited mixed inhibition. Biochanin A and/or formononetin may exert anticarcinogenic effects directly by acting as competitive substrates for CYP1B1 or indirectly through their metabolites daidzein and genistein, which inhibit CYP1B1.
- Roberts, Dean W.,Doerge, Daniel R.,Churchwell, Mona I.,Da Costa, Goncalo Gamboa,Marques, M. Matilde,Tolleson, William H.
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p. 6623 - 6632
(2007/10/03)
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- Synthesis of Naturally Occuring Pratensein and 6,8-Di-C-prenylpratensein
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Pratensein (4a) has now been synthesized in two ways.The first route involves condensation of phloroacetophenone dibenzyl ether (1) with O-benzylisovanillin (2) and oxidative cyclization of the resulting chalcone (3) with Tl(NO3)3-MeOH followed by boiling with HCl.In the second route 2,4,6,3'-tetrahydroxy-4'-methoxydesoxybenzoin (5) is treated with DMF, CH3SO2Cl and BF3-Et2O.When pratensein is reacted with 3-hydroxy-3-methyl-1-butene in the presence of BF3-Et2O and dioxan, it gives the naturally occuring 6,8-di-C-prenylpratensein (6a).
- Jain, A. C.,Bambah, P. K.
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p. 488 - 490
(2007/10/02)
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