Identification of the constituents and metabolites in rat plasma after oral administration of HuanglianShangqing pills by ultra high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry.

An ultra high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry method was established to detect and identify the chemical constituents and metabolites of HuanglianShangqing pill (HLSQ) in vitro and in vivo. A total of 96 compounds were characterized in HLSQ extracts. In vivo, 45 prototype components and 53 metabolites of HLSQ were detected in rat plasma and tentatively identified, three of which are new. The novel metabolic pathways of rhein and hesperetin were revealed. The bioactive compounds of HLSQ undergo phase I metabolic routes of hydrogenation, hydroxylation, hydrolysis, demethylation and phase II metabolic routes of glucuronide, sulfation, acetylation and methylation. Among these, glucuronide conjugation is the main metabolic pathway of the active compounds of HLSQ in rat plasma.