| This paper studied the extraction of the steroid saponin from Dioscorea zingiberensis C.H.Wright and Dioscorea nipponica Makion,and the separation of monomer saponins,bioconversion of total saponins and the separation of the hydrolysate.Firstly,the total saponin was extracted from Dioscorea zingiberensis C.H.Wright and Dioscorea nipponica Makion using ethanol.107g of total saponins was obtained from 3.15 g of Dioscorea zingiberensis C.H.Wright,the yield was 3.39%;250 g of total saponins was obtained from 4 kg of Dioscorea nipponica Makion,and the yield was 6.25%.The content of saponins in Dioscorea nipponica Makion was 1.8 times of that of Dioscorea zingiberensis..It is shown from the comparison of the two total saponins,the main ingredient in Dioscorea zingiberensis C.H.Wright were protodioscin,Dioscin and Protogracillin,their content was 40%,25%and 20%,respectively.In contrast,the main unknown water-soluble saponin was about 76%,and little Diosgenin and Trillin.But there are no protodioscin and dioscin in Dioscorea zingiberensis C.H.Wright.Sillica gel chromatography was used to separate the total saponin,four pure saponins including Trillin,Protogracillin and two unknown saponins were obtained from Dioscorea zingiberensis C.H.Wright,and its purity was more than 90%;Dioscin and protodioscin were separated from Dioscorea nipponica Makion total saponins,and its purity was 95%and 98%.After biotransformation of the two total saponins,the main hydrolysate from Dioscorea zingiberensis C.H.Wright were diosgenin,Trillin and Gracillin;the main hydrolysate from Dioscorea nipponica Makion were anemoside A,Trillin and diosgenin.The hydrolysate from 24.0 g of total saponins from Dioscorea nipponica Makion was desugar and decolorated to obtain 15.8 g product,its yield was 65.8%.After separated by silica gel,8.25 g anemoside A and 0.18 g Gracillin were obtained.Crystallization was used to further purified anemoside A,6.27 g anemoside A was obtained,and its purity was 98%. |
