Two sulfonate metabolites of physalin A in rats.

1. Physalin A is a bioactive withanolide isolated from the natural plantPhysalis alkekengivar.franchetii(Solanaceae), a common traditional Chinese herbal medicine. This study aims to investigate the metabolites of physalin Ain vivo. 2. Two metabolites (M1andM2) were characterized as sulfonate metabolites in the feces obtained from rats treated with physalin A orally at a dose of 15 mg/kg/day for 3 days, by application of a UPLC-Q/TOF-MS method. Furthermore, formation of the two sulfonate metabolites was verified by chemical synthesis and NMR, including1H NMR,13C NMR and two-dimensional NMR. The structures ofM1andM2were identified to be 3α-sulfo-2,25β,27-trihydrophysalin A and 3α,27-disulfo-2,25α-dihydrophysalin A, respectively. 3. In summary, this study indicated that physalin A could be biotransformed to sulfonate metabolites with strong polarity, which contributed to the elimination of physalin A. A rare metabolic pathway has been revealed in this study. [ABSTRACT FROM AUTHOR]