Metabolic Profiling of Alpinetin in Rat Plasma, Urine, Bile and Feces after Intragastric Administration

Alpinetin, a bioactive flavonoid, has been known to have a diverse therapeutic effect, with namely anti-inflammatory, anticancer and antioxidant effects with low systemic toxicity. This study aimed to obtain metabolic profiles of alpinetin in orally administrated rats. The metabolites of alpinetin were systematically analyzed and identified by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). The chromatographic separation was achieved on a High Strength Silica (HSS) T3 (1.8 mu m, 2.1 x 100 mm) column with the mobile phase consisting of water containing 0.1% formic acid and acetonitrile with 0.1% formic acid via gradient elution. An extracted ion chromatogram strategy based on multiple prototype/metabolite intermediate templates and 71 typical metabolic reactions was proposed to comprehensively profile the metabolites of alpinetin. With the metabolite profiling strategy, altogether 15 compounds were recognized from urine, plasma, bile and feces of rats after intragastric administration of alpinetin for the first time. The prototype, glucuronide conjugates and phenolic acids metabolites were the probable predominant form of alpinetin in rats. This work showed a comprehensive study of the probable metabolic pathways of alpinetin in vivo, which could provide meaningful information for future pharmacological studies.