Metabolism of Oleracone K from Portulaca oleracea L. in Rat Plasma by Ultra-high-performance Liquid Chromatography/ Electrospray Ionization Quadrupole Time-of-flight Tandem Mass Spectrometry

Oleracone K is a typical homoisoflavone isolated from the medicinal herb Portulaca oleracea L. which was widely used in which the compound had been found to possess various activities such as antioxi-dant, analgesic, antitumor, and anti-aging. However, few studies have been carried out on its in vivo. In this study, the pharmacokinetic study of the oleracone K in rats was initially performed using ultra -high-perfor-mance liquid chromatography (UHPLC), which showed significant and uncommon metabolic phenomena in the assay. Therefore, the identification of metabolites of oleracone K in rat plasma after a single intravenous dose (2.2 mg/kg) was further investigated by a rapid, sensitive, and specific ultra-high-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-Q-TOF/MS) method, and seven metabolites were identified and the possible metabolic pathways were hypoth-esized to be oxidation, hydroxylation, methylation, glucuronidation, and sulfation.