Study on metabolism of scutellarin in rats by HPLC-MS and HPLC-NMR.

Scutellarin is the major active constituent of Scutellaria barbata D. The metabolism of scutellarin has been investigated in rats. The solid-phase extraction and HPLC-DAD methods were established to separate and analyse metabolites. Five metabolites (M1-M5) were identified by enzymatic hydrolysis, HPLC-DAD, HPLC-MS and HPLC-NMR. M1 and M3 were conjugates of scutellarin with two sulfate groups, which have not been reported in natural plants. M2 was scutellarin; M4 was 6-methyl-scutellarin; and M5 was 6-methyl-scutellarein. The metabolic pathway was proposed.