An integrated strategy to delineate the chemical and dynamic metabolic profile of Huachansu tablets in rat plasma based on UPLC-ESI-QTOF/MS^E

Metabolic research is a key method to understand the fate of traditional Chinese medicine (TCM) prescription in vivo and help to explain its pharmacological effects. Huachansu (HCS) tablets are prepared from the dried skin of Bufo gargarizans (Cantor, 1842), which have the effects of detumescence and analgesia, and used in the treatment of middle and advanced tumors. However, an in-depth understanding of the chemical components of HCS tablet and its metabolism in vivo is lacking. In this study, an integrated analytical strategy based on UPLC-ESI-QTOF/MS^E was developed to efficiently identify the chemical components, the absorbed prototype compounds and metabolites of HCS tablets given by gavage in rats, and track their dynamic changes. As a result, 77 chemical components of HCS tablets were characterized, including 46 bufadienolides, 11 alkaloids, 10 amino acids and organic acids, 9 nucleosides, and 1 other component. Further more, 16 prototype compounds and 47 metabolites (38 bufadienolides-related and 9 alkaloids-related) were identified in rat plasma. Through the dynamic detection of prototype compounds and metabolites of HCS tablets in vivo, the phenomenon that 3 prototype compounds and 16 metabolites reappeared after a period of disappearance from the plasma was found. Additionally, 8 prototype compounds with large intensity in HCS tablet samples were not detected in the plasma samples of rats given HCS tablets but had metabolites within 0-24 h after administration, indicating that these components were rapidly absorbed and metabolized into metabolites in vivo. It was also observed that 9 metabolites can be driven from various prototype compounds and reach high concentrations in a short time. This study comprehensively identified the xenobiotics and metabolites of HCS tablets in rat plasma sample, systematically discussed their dynamic metabolic process in vivo, which laid a foundation for studying the pharmacodynamic substances of HCS tablets.