Emodin Studies on Pharmacokinetics and Distribution in Rat Liver after Polygonum cuspidatum Sieb. et Zucc. Extract Administration

A rapid, sensitive and selective high-performance liquid chromatography method (HPLC) has been developed and validated to investigate the pharmacokinetics and distribution profile of emodin in rats after taking Polygonum cuspidatum Sieb.et Zucc. and to reflect Polygonum cuspidatum Sieb.et Zucc.'s in-vivo changing rule in rats. The emodin in the biosamples was tested, and the plasma emodin concentration-time curve and liver emodin concentration-time curve were plotted. The pharmacokinetic model of emodin fitted to open two-compartment model in rat. The emodin was rapidly absorbed with peak plasma concentration occurring at 9 min after administration of the extract. The Cmax was 3.973±0.535 μg/mL, and its calculated elimination half life was 11 h. The emodin concentration-time curve in the liver showed that Tmax and Cmax were 10 min and 9.654±1.41 μg/g, respectively. The emodin concentrations both in the plasma and liver decreased notably, within 24 h after administration. The emodin in Polygonum cuspidatum Sieb.et Zucc. was absorbed rapidly into the blood and distributed quickly into the liver of the rat. The results of this study may provide reference to in-vivo pharmacokinetics study of anthraquinones, which are emodin analogs and help explain the material base of the pharmacologic effect of Polygonum cuspidatum Sieb.et Zucc.