Abstract: AIM: To study the enzyme kinetics of genistein metabolism and the effects of selective CYP450 inhibitors on the metabolism of genistein in rat liver microsomes. METHODS: Rat liver microsome was used to perform enzyme kinetic studies.Various selective CYP inhibitors were used to investigate their inhibitory effects on the metabolism of genistein and the principal CYP isoform involved in genistein metabolicly ring.RESULTS: The metabolism of genistein was significantly inhibited by furafylline while quinidine, sulfaphenazole, tranylcypromine diethyldithiocarbamate and ketoconazole showed little inhibitory effect on the metabolism of genistein.CONCLUSION: CYP1A2 is involved in genistein metabolism.CYP1A2 inhibitors and genistein may interact metabolicly, thereby reduced the rate of genistein metabolism.

Key words: genistein, microsome, pharmacokinetics, enzyme kinetics, CYP450, phytoestrogens