Metabolic profile of irisolidone in rats obtained by ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry.

Abstract Irisolidone, a major isoflavone found in Pueraria lobata flowers, exhibits a wide spectrum of bioactivities, while its metabolic pathway in vivo has not been investigated. In this study, an ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF MS) method was employed to investigate the in vivo metabolism of irisolidone in rats. Plasma, bile, urine, and feces were collected from rats after a single 100 mg/kg oral dose of irisolidone. Protein precipitation, solid phase extraction (SPE) and ultrasonic extraction were used to prepare samples of plasma, bile/urine, and feces, respectively. A total of 46 metabolites were detected and tentatively identified based on the mass spectral fragmentation patterns, elution order or confirmed using available reference standards. The metabolic pathways of irisolidone in rats included decarbonylation, reduction, demethylation, demethoxylation, dehydroxylation, hydroxylation, sulfation, and glucuronidation. The relative content of each metabolite was also determined to help understand the major metabolic pathways of irisolidone in rats.