Metabolic profiles of Xiao Chai Hu Tang in mouse plasma, bile and urine by the UHPLC–ESI-Q-TOF/MS technique

Xiao Chai Hu Tang (XCHT) is sold as traditional medicine or dietary supplement in worldwide. To understand metabolism profile of traditional medicine is key point in their logical pharmacological research and clinical application. Based on our previous research of the chemical and absorption signature of XCHT in vitro, we proposed a novel strategy to identify the bioactive components of XCHT in vivo. This strategy have two steps: firstly, based on the parents' database in vitro, built-in and editable biotransformations for phase I and phase II metabolism reactions with MassHunter Metabolite ID software (building metabolites database). Secondly, mouse plasma, bile and urine samples were analyzed by UHPLC–ESI-Q-TOF/MS technique, and the absorbed parents and metabolites were compared and identified with the XCHT's digital library using MassHunter Metabolite ID software. In total, 27 parent compounds and 26 metabolites of XCHT were identified in vivo, 2′-O-xylosyl saikosaponin b2 or b1 was reported for the first time. Saponins and their related metabolites were predominantly excreted into the bile, but flavonoids were excreted by both hepatic as well as renal excretion. Flavonoids, saponins, gingerol and their related metabolites were the absorbed components in cardiovascular system and bioactive components of XCHT. Phase I reactions (hydrolysis, hydroxylation and oxidation) and phase II reactions (glucuronidation) were identified and involved in the mouse metabolism of XCHT.