Effect of Bakumondo-to on cytochrome P450 activities in rat liver microsomes

Bakumondo-to is a traditional herbal medicine. It has been widely used for the treatment of chronic airway diseases. Recently, it was reported that several herbal medicines affected cytochrome P450 (CYP). However, there is little information about the effects of Bakumondo-to on CYP activities. In this study, we evaluated the effects of Bakumondo-to on CYP activities in rat liver microsomes. Rats were orally treated twice a day with Bakumondo-to at doses of 2.0 g/kg body weight/day for 4 days. CYP activities were determined in liver microsomes isolated from treated rats. CYP1A2, CYP2C, and CYP3A activities were measured using their specific substrates [7-methoxyresorufin, 7-methoxy-4-(trifluoromethyl)-coumarin, and 7-benzyloxyquinoline, respectively]. Bakumondo-to decreased CYP1A2 activity by 42.5 ± 7.8%, increased CYP2C activity by 158.0 ± 29.6%, and decreased CYP3A activity to 81.5 ± 7.8% of the control level. Activities were expressed as percentages of the control. Bakumondo-to induced CYP2C activity and decreased CYP1A2 activity; it may cause drug-herbal interactions. It is suggested that combinations of Bakumondo-to and drugs that are metabolized by CYP1A2 and CYP2C should be carefully used in clinical settings.