Study on metabolic pathways and metabolites of Diosbulbin B in vitro / 中草药

ABSTRACT

Objective: To investigate the metabolic stability, the main CYP450 enzymes phenotypes and metabolites of Diosbulbin B based on in vitro metabolism model. Methods: For metabolic stability study, UPLC-MS/MS was used to detect the remaining Diosbulbin B content in the incubation solution after being incubated with human and rat liver microsomes, respectively. Ten recombinant human CYP450 enzymes (1A1, 1A2, 1B1, 2A13, 2A6, 2B6, 2D6, 2C9, 2C19, 3A4) were used for identifying the metabolic enzyme phenotypes of Diosbulbin B. Moreover, the major metabolic enzyme phenotype for the metabolism of Diosbulbin B was confirmed and verified by the rat isolated hepatic perfusion model. The metabolites of Diosbulbin B in human and rat liver microsomes were determined by LC-MS/MS. Results: The metabolic percentage of Diosbulbin B in human and rat liver microsomes were 37% and 59%, respectively. Its half-lives t1/2 in human and rat liver microsomes were 97.4 and 52.3 min, respectively. The intrinsic clearance rates CLint in human and rat livers were 8.23 and 23.9 mL/(min•kg), and liver clearance CLh in human and rat livers were 5.89 and 16.8 mL/(min•kg). It can be found that the metabolic rate of Diosbulbin B in rat liver microsomes was faster than in human liver microsomes. There were five CYP enzymes, including 3A4, 2C19, 2C9, 1A13 and 1A1, related to the metabolism of Diosbulbin B, especially CYP3A4. The hepatic perfusion experimental results showed that the metabolism of Diosbulbin B was inhibited by ketoconazole, and the inhibitory effect was enhanced along with the increasing dosage of ketoconazole, which confirmed that CYP3A4 played an important role in metabolism of Diosbulbin B. There was one metabolite (M1) of Diosbulbin B has been found in both human and rat liver microsomes incubation. Conclusion: The metabolic rate of Diosbulbin B in rat liver microsomes was faster than human liver microsomes. The CYP3A4 plays a leading role in the metabolism of Diosbulbin B. And a demethylated metabolite of Diosbulbin B was appeared in both human and rat liver microsomes incubation.