Effects of Danhong injection,a traditional Chinese medicine,on nine cytochrome P450 isoforms in vitro

Danhong injection (DHI) is made from Salvia miltiorrhiza Bunge. and Carthamus tinctorius L. extract and is widely used in the clinical treatment of cardiovascular and cerebrovascular diseases. This study aimed to evaluate the effect of DHI on cytochrome P450 (CYP450) enzymes in vitro to predict drug–drug interactions based on CYP450 as combination therapy. To assess the inhibitory effect of DHI on CYP450, we detected the IC₅₀ value of DHI on CYP450 in vitro by liquid chromatography/tandem mass spectrometry (LC–MS/MS). Simultaneously, the induction effect of DHI on CYP450s was also evaluated. The relative induction ratios of DHI on CYP1A2, CYP2B6 and CYP3A4 activity were calculated by LC–MS/MS. The expression level of CYP3A4 mRNA was determined by reverse transcription PCR (RT‐PCR). The LC–MS/MS data showed DHI intensively inhibit CYP2A6 activity and the intensity of inhibition was followed by CYP2C8, CYP3A4, CYP2C19, CYP2B6, CYP2D6, CYP1A2, CYP2E1 and CYP2C9 in vitro. The results of RT‐PCR showed that there is a certain induction of DHI on CYP3A4 mRNA in human primary hepatocytes in vitro. The study suggested that drug–drug interactions might occur in clinical co‐administration of drugs owing to the CYP2A6 inhibition and CYP3A4 induction.