Exploration of the profiles of steroidal saponins from Rhizoma Paridis and their metabolites in rats by UPLC‐Q‐TOF‐MS/MS

Abstract Introduction Steroidal saponins characterised by intricate chemical structures are the main active components of a well‐known traditional Chinese medicine (TCM) Rhizoma Paridis. The metabolic profiles of steroidal saponins in vivo remain largely unexplored, despite their renowned antitumor, immunostimulating, and haemostatic activity. Objective To perform a comprehensive analysis of the chemical constituents of Rhizoma Paridis total saponins (RPTS) and their metabolites in rats after oral administration. Method The chemical constituents of RPTS and their metabolites were analysed using ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry (UPLC‐Q‐TOF‐MS/MS). Results A reliable UPLC‐Q‐TOF‐MS/MS method was established, and a total of 142 compounds were identified in RPTS. Specifically, diosgenin‐type saponins showed the diagnostic ions at m/z 415.32, 397.31, 283.25, 271.21, and 253.20, whereas pennogenin‐type saponins exhibited the diagnostic ions at m/z 413.31, 395.30, and 251.20. Based on the characteristic fragments and standard substances, 15 specific metabolites were further identified in the faeces, urine, plasma, and bile of rats. The metabolic pathways of RPTS, including phase I reactions (de‐glycosylation and oxidation) and phase II reactions (glucuronidation), were explored and summarised, and the enrichment of metabolites was characterised by multivariate statistical analysis. Conclusion The intricate RPTS could be transformed into relatively simple metabolites in rats through de‐glycosylation, which provides a reference for further metabolic studies and screening of active ingredients for TCM.