Multiple Component Pharmacokinetics after Oral Administration of Gnaphalium affine Extract in Rats

Gnaphalium affine is traditionally used to treat hyperuricemia and gout in China. Recently, the hypouricemic and renal protective effects of G. affine extract (GAD) have been deeply evaluated. However, little is known about the pharmacokinetics (PKs) of bioactive constituents in GAD. This study is aimed at investigating the individual and holistic pharmacokinetics of 10 bioactive components (including caffeic acid, caffeoylquinic acids, and flavonoids) in rats after single and multiple administrations of GAD. GAD is orally dosed to normal male rats at doses of 225, 450, or 900 mg/kg/day for 10 consecutive days and also orally administrated to uric acid nephropathy (UAN) rats at a dose of 900 mg/kg/day for 28 consecutive days. Integrated PKs of multiple components are calculated by area under the curve (AUC)-based weighting approach. All the components show a double-peak phenomenon in terms of their plasma concentration-time curves, suggesting that the components undergo enterohepatic circulation. The integrated AUC increases in a good dose-proportional manner with GAD dose. Compared with that in normal rats, the plasma exposure of caffeic acid and caffeoylquinic acids increases by 2.3- to 4.3-fold after 10-day chronic treatment of 900 mg/kg GAD in UAN rats. Modest drug accumulation is observed after 28-day chronic treatment.