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Analysis of Biliary Excretion of Icariin in Rats
- Wu, Yu-Tse, Lin, Chia-Wen, Lin, Lie-Chwen, Chiu, Allen W., Chen, Kuang-Kuo, Tsai, Tung-Hu
- Journal of agricultural and food chemistry 2010 v.58 no.18 pp. 9905–9911
- biliary tract, excretion, rats, animal models, bioactive properties, Epimedium, high performance liquid chromatography, Oriental traditional medicine, herbal medicines, bioavailability
- Icariin is a bioactive herbal ingredient isolated from Epimedii Herba. This study evaluates the distribution of icariin in rats by microdialysis sampling and high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Microdialysis probes were simultaneously placed in the jugular vein, brain striatum, and bile duct of each anesthetized rat for sampling after the administration of icariin (dose = 10 or 20 mg/kg) via the femoral vein. The role of P-glycoprotein (P-gp) on icariin distribution was assessed by pretreatment with cyclosporine (CsA, dose = 20 mg/kg). This study is the first report of the biliary excretion of icarin in rats, defined as the blood-to-bile distribution (k value), calculated by dividing the area under the concentration−time curve (AUC) of icariin in bile by that in blood (k = AUC(bile)/AUC(blood)). The k values were 19.0 ± 5.9 and 18.8 ± 3.8 at the doses of 10 and 20 mg/kg, respectively. The decreased biliary excretion of icariin due to pretreatment with CsA was evidenced by the reduced k values (18.8 ± 3.8 vs 9.9 ± 1.9, p = 0.005). This work demonstrates that biliary excretion is the major elimination pathway for icariin disposition and that transporters, such as P-gp, might be related to icariin’s biliary excretion.