INHIBITION OF METHOXYRESORUFIN DEMETHYLASE ACTIVITY BY FLAVONOIDS IN HUMAN LIVER-MICROSOMES

Flavonoids are a class of dietary phytochemicals with anticarcinogenic properties. A series of ten structurally related flavonoids were eval uated for their effect on methoxyresorufin O-demethylase (MROD) activi ty in human liver microsomes. Ail compounds inhibited this cytochrome P450 1A2 (CYP1A2) mediated activity. 3,5,7-Trihydoxyflavone (galangin) was the most potent inhibitor, followed by 3-hydroxyflavone and flavo ne. The relative inhibitory potency of flavonoids is related to their structures. The results suggest that flavonoids may modulate pharmacol ogical and toxicological effects mediated by CYP1A2. Published by Else vier Science Inc.