In vitro inhibition of five traditional Chinese medicine injections on rat liver microsomal CYP3A

Abstract

Qingkailing injection (QKLI), Jinnaduo injection (JNDI), Shuxuetong injection (SXTI), Shenmai injection (SMI) and Kangai injection (KAI) are widely used in China. To predict the herb-drug interactions in clinical application, they were evaluated for their in vitro inhibition effect on CYP3A in rat liver microsomes. The rat liver microsomes were incubated with different doses of 5 kinds of traditional Chinese medicine injections (TCMIs) in the present of testosterone, a specific substrate of CYP3A. 6beta-hydroxytestosterone, the metabolite of testosterone, was monitored by HPLC to compare the inhibition effect of 5 TCMIs on CYP3A in rat liver microsomes. Ketoconazole was used as a positive control. 10% QKLI reduced the formation of 6beta-hydroxytestosterone by approximately 93.0%, which is more significant than other four TCMIs. The half maximal inhibitory concentration (IC50) and the enzyme-inhibitor constant K(i) were 1.0% and 0.7% respectively. QKLI showed much stronger inhibition activity against CYP3A, comparing to other 4 TCMIs. The results revealed that QKLI may be involved in herb-drug interactions by inhibition of CYP3A.