Metabolite identification and excretion of pinocembrin-7-O-β-D-glucoside in rats by UHPLC/MS

Pinocembrin-7-O-β-D-glucoside (PCBG) isolated from Penthorum chinense Pursh was proven to display a wide range of pharmacological effects including hepatoprotection, anti-hepatoma and antifungal activities, etc. The research aims to qualitatively analyze the metabolites of PCBG in rat plasma, urine, bile and feces, and further perform the excretion study of PCBG and its major metabolite pinocembrin (PCB). Fifteen rats were divided into three groups (n=5 for each group) for blood, bile, urine and feces collection, respectively. After PCBG suspension was intragastrically administered to rats at 50 mg/kg, biological samples were collected and processed. The metabolites in each matrix were detected by UHPLC-Q-Exactive-MS/MS. A total of 111 metabolites were observed in plasma, urine, bile and feces, which include hydroxylated, sulfated and glucuronized metabolites, etc. In addition, an UHPLC-MS/MS method was established and applied for the excretion quantification of PCBG and PCB in rat urine, bile, and feces samples. Studies on excretion have shown that PCBG is mainly excreted through feces. The cumulative excretion rates of PCBG and PCB in rat urine, bile and feces were (4.5±2.4)%, (0.2±0.1)% and (18.4±10.5)%, respectively. After hydrolysis by β-glucuronidase/sulfatase, the excretion rates of PCB in urine and bile were (5.7±2.8)% and (8.9±4.2)%. This study contributes to preclinical research on PCBG and explains its pharmacological effects.