title: Metabolism of dietary flavonoids in liver microsomes.
abstract: Flavonoids undergo substantial hepatic metabolism and the metabolites might significantly contribute to the effects of these dietary constituents. The metabolites of flavonoids in liver can be summarized as follows: 1) For flavones, the hydroxylation appears to occur at the C-4'-, C-3', C-6 and C-8- position when there is a single or no hydroxy group on the B-ring. The methoxyl groups positioned at the C-7, C-6 or C-4'- position of flavones are demethylated. The glucuronidation occurs at the 6, 7, 4' or 3'- hydroxyl moiety. Flavone glycosides and aglycones appear to undergo similar metabolic pathways. 2) For flavonols, the hydroxylation appears at the 3' and 4'- position and flavonols with a 4'-methoxy group are easily O-demethylated to their corresponding hydroxylated analogs. The glucuronidation takes place at the 7, 3, 3' and 4'- hydroxyl moiety. 3) For isoflavones, the microsomal hydroxylation is observed at the C-3'-, C-6 and C-8- position when there is a single or no hydroxy group on the B-ring. The demethylation takes place at the C-6- or C-4'- position when there is one methoxy group on C-4' or C-6-position, respectively. The glucuronidation occurs at the 4, or 5- hydroxyl moiety. 4) For chalcones, the C-3'-, and C-8- positions undergo hydroxylation. The C-8- position is a very active site for metabolism of chalcones.
authors: Department of Biology, Shanghai Normal University, Shanghai, P.R. China. jianboxiao@yahoo.com
authors: Jianbo
authors: J
authors: Xiao
authors: Petra
authors: P
authors: Högger
mesh_terms: D000818:Animals; D004032:Diet; D005419:Flavonoids / Q000494:pharmacology*; D006801:Humans; D008862:Microsomes, Liver / Q000378:metabolism*
chemical_list: D005419:Flavonoids