Metabolic studies on the total phenolic acids from the roots of Salvia miltiorrhiza in rats.

Phenolic acids are the main active constituents of Salvia miltiorrhiza Bunge. The metabolism of total phenolic acids from the roots of Salvia miltiorrhiza in rats was investigated. A sample preparation method combining the solid-phase extraction with liquid-liquid extraction was established to separate metabolites from the biological matrix. HPLC-UV and HPLC-MS methods were employed to analyze the metabolites. Five metabolites (M1-M5) were identified by HPLC-MS analysis and comparison with those of the reference standards. The fi ve metabolites were characterized as danshensu (M1), caffeic acid (M2), ferulic acid (M3), isoferulic acid (M4) and methylized ferulic acid (M5), respectively. The possible metabolic pathway of the phenolic acids is proposed.