Diterpene quinone tanshinone IIA selectively inhibits mouse and human cytochrome p4501A2.

1. Tanshinone IIA is the main active diterpene quinone in the herbal medicine Salvia miltiorrhiza. In untreated mouse liver microsomes, tanshinone IIA selectively inhibited 7-ethoxyresorufin O-deethylation (EROD) and 7-methoxyresorufin O-demethylation (MROD) activities without affecting the oxidation of benzo(a)pyrene, tolbutamide, N-nitrosodimethylamine and nifedipine.

Effects of Wu-chu-yu-tang and its component herbs on drug-metabolizing enzymes.

The compound herbal medicine Wu-chu-yu-tang is used for the treatment of migraine and vomiting accompanying a cold. To assess the interactions of herb and drug metabolism, effects of Wu-chu-yu-tang on hepatic and renal cytochrome P450 (CYP), UDP-glucuronosyl transferase (UGT) and glutathione S-transferase (GST) were studied in C57BL/6J mice. Treatment of mice with 5 g/kg per day Wu-chu-yu-tang for 3 days caused 2.