The disposition and pharmacokinetics of Dioscorea nipponica Makino extract in rats

This study was aimed to investigate the disposition and pharmacokinetics of the total saponins of dioscorea (TSD) in rats. Male Sprague-Dawley rats were orally administrated with super(3)H 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 TSD in 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 plus or minus 4.48 h, T sub(max)= 6.5 plus or minus 0.71 h, AUC = 119400 plus or minus 421097.67, and C sub(max) = 2643.33 plus or minus 192.26 dpm/ml. There was 51.609% of super(3)H labeled substance excreted in 24 h. These results suggested that blood concentration of super(3)H-TSD was extremely low and the majority of TSD was excreted in the feces. The TSD was extensively 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 TSD was excreted in vivo very slowly.