The fate of Phellamurin in rats

Phellamurin is a flavonoid glycoside that is abundant in the leaves of Phellodendron wilsonii Hayata et Kanehira (Rutaceae). The metabolism and disposition of phellamurin were investigated in rats. Doses of 100 mg/kg and 200 mg/kg were orally administered to rats and blood samples were withdrawn by cardiopuncture at specific times. Serum concentrations of the aglycone were determined by an HPLC method prior to and after hydrolysis with β-glucuronidase. The mobile phase was acetonitrile: H₂O (containing 1% acetic acid, 38:62, v/v). The pharmacokinetic parameters were calculated by using the noncompartment model of WINNONLIN. Our results indicate that the parent compound was not absorbed. Hydrolysis to phellamuretin resulted in rapid absorption and subsequent conversion to glucuronides. The pharmacokinetic parameters after two doses were not significantly different. Phellamuretin and phellamuretin glucuronides accounted for 20 % and 80 % of the metabolites of phellamurin, respectively, for both doses.