title: Identification of inhibitory component in cinnamon--O-methoxycinnamaldehyde inhibits CYP1A2 and CYP2E1-.
abstract: The Cinnamomi Cortex and Ephedra Herba were found to more strongly inhibit aminopyrine N-demethylation in rat liver microsomes compared to other constituents 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 and 4-nitrophenol were used as probe substrates for CYP1A2 and CYP2E1, respectively, the OMCA was shown to 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 microM) was somewhat potent compared to that observed on phenacetin O-deethylation (K(i)=13.7 microM) in rat liver microsomes.
authors.affiliation: Division of Pharmacy, Chiba University Hospital, Faculty of Medicine, Chiba University, Japan. a-hasegawa@umin.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hasegawa
authors.forename: Masaki
authors.initials: M
authors.lastname: Yoshino
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Nakamura
authors.forename: Itsuko
authors.initials: I
authors.lastname: Ishii
authors.forename: Toshiko
authors.initials: T
authors.lastname: Watanabe
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kiuchi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ohmori
authors.forename: Mitsukazu
authors.initials: M
authors.lastname: Kitada