Studies on In Vitro Metabolites and Cytochrome P450 Isoforms Involved in Microsomal Metabolism of Isofraxidin by LC-MS n and Specific Inhibitor Probes

Isofraxidin (IF) is a coumarin compound that can be isolated from some medicinal plants, such as Acanthopanax senticosus, Sarcandra glabra etc. It has many bio-activities such as anti. fatigue, anti-bacterial, anti-tumour activity and immuno-accommondating action. In this study, LC-MSn method was developed for analyzing isofraxidin and its metabolites in rat liver microsomes. The results showed that the optimum incubations time for the isofraxidin in rat liver microsomal was 2 h. Five metabolites were found and characterized in rat liver microsomal incubations by LC-MSn analysis. Various specific inhibitors of cytochrome P450 (CYP450) as probes were used to identify the isoforms of CYP450. Our research results suggested that isofraxidin metabolism by rat liver microsomes was significantly correlated with CYP 3A, CYP 2C and CYP 2E1 isoforms related activity.