Abstract

This study was aimed to investigate the disposition and pharmacokinetics of the total saponins of dioscorea (TSD) in rats. Male Sprague-Dawley rats were orallyadministrated with ³H labeled TSD at a single dose ratio of 80 mg TSD per 1 kg rat.Blood samples and feces were collected at different time points to measure the level of TSD activity. At the final time point, determination of the disposition of TSDin lung, kidney, heart, liver, adrenal, and small intestine were performed. From the blood samples’ emission of radioactivity, pharmacokinetic parameters were derived as T1/2 = 33.33 ± 4.48 h, T_max = 6.5 ± 0.71 h, AUC = 119400 ± 421097.67, and C_max = 2643.33 ± 192.26 dpm/ml. There was 51.609% of ³H labeled substance excreted in 24 h. These results suggested that blood concentration of ³H-TSD wasextremely low and the majority of TSD was excreted in the feces. The TSD wasextensively distributed to multi-tissues. The radioactivity level was measured to be the highest in the liver, adrenal gland, and wall of the gastrointestinal tract. The radioactivity of TSD was still being detected in blood after 96 h. This showed TSDwas excreted in vivo very slowly.

Key words: Total saponins of dioscorea, disposition, pharmacokinetics, ³H labeled.