Isolation and identification of urinary metabolites of tectoridin in rats

Tectoridin is an active isoflavone from the rhizome of Belamcanda chinensis and flower of Pueraria thomsonii Benth, possessing an anti-inflammation action and the protective effect against ethanol-induced intoxication and hepatic injury. The metabolism of tectoridin was investigated in rats. Nine metabolites were isolated by using repeated chromatographic methods and identified by spectroscopic methods including UV, IR, mass spectrometry, and NMR experiments. A new compound was determined as tectorigenin-7-O-beta-D-glucuronide (M-1), together with eight known compounds identified as irisolidone-7-O-beta-D-glucuronide (M-2), tectorigenin-7-O-sulfate (M-3), tectorigenin-4'-O-sulfate (M-4), tectorigenin (M-5), irisolidone (M-6), isotectorigenin (M-7), genistein (M-8), and daidzein (M-9), respectively. The metabolic pathway of tectoridin was proposed, which is important to understand its metabolic fate and disposition in humans.