Identification of inhibitory component in cinnamon -O-methoxycinnamaldehyde inhibits CYP1A2 and CYP2E1

摘要

The Cinnamomi Cortex and Ephedra Herba were found to more strongly inhibit aminopyrine N-demethylation in rat liver microsomes compared to other constitutents included in Sho-seiryu-to.The component inhibiting drug oxidations catalyzed by CYP1A2 and CYP2E1 was isolated from Cinnamomi Cortex,and was identified as o-methoxycinnamaldehyde (OMCA).When phenacetin and4-nitrophenol were used as probe substrates for CYP1A2 and CYP2E1,respectively,the OMCA was shownto be a competitive inhibitor against CYP1A2 while it was a mixed type inhibitor against CYP2E1.The inhibitory effect of OMCA on 4-nitrophenol 2-hydroxylation(K_i=6.3 muM) was somewhat potent compared to that observed on phenacetin O-deethylation (K_i=13.7muM) in rat liver microsomes.