Acute toxicity and sub-chronic toxicity of steroidal saponins from Dioscorea zingiberensis CHWright in rodents

Ethnopharmacological relevance: Steroidal saponins from Dioscorea zingiberensis are widely used in China for curing cardiovascular diseases. However, there was little toxicological information available on them. Aim of the study: The study evaluated potential toxicity of the steroidal saponins and analyzed the metabolites in rats. Materials and methods: For the acute study, the steroidal saponins were administered to kunming mice in single doses of 112.5-9000mg/kg given by gavage. General behavior adverse effects, mortality and liver histopathological changes were examined. For the sub-chronic toxicity study, Sprague-Dawley rats were gavaged at doses of 127.5, 255 and 510 mg/kg/day for 30 days, then examined the biochemical and hematological parameters. Metabolites in serum were analyzed by HPLC-MS. Results: The steroidal saponins caused dose-dependent general behavior adverse effects, mortality and liver histopathological changes in the acute toxicity study. In the sub-chronic toxicity study, 510 mg/kg/day of steroidal saponins increased total bilirubin (TBIL) in serum and decreased protein content in liver significantly. The metabolic process of TBIL in liver includes TBIL intaking, conjugated bilirubin forming, conjugated bilirubin excreting to biliary passage. Treatment with high dose of the steroidal saponins in vivo may lead to vacuolization of the cytoplasm of hepatocytes and canalicular cholestasis. In all doses used in the experiment, the steroidal saponins decreased aspartate aminotransferase (GOT), alanine aminotransferase (ALT) and alkaline phosphatase (AKP) in serum and increased reduced glutathione hormone (GSH), glutathione reductase (GR) and glutathione S-transferases (GST) in liver. Diosgenin was the main metabolite in serum. Conclusions:The steroidal saponins did not show any sign of toxicity up to oral dose of 562.5 mg/kg in mice. No significant changes of biochemical and hematological parameters in rats (except at 510 mg/kg/day). it was concluded that the steroidal saponins did not appear to have significant toxicity in their traditional uses. (C) 2009 Elsevier Ireland Ltd. All rights reserved.