Preparationing Diosgenin From Dioscorea Zingiberensis

Dioscorea zingiberensis contains relatively high concentration of Diosgenin and has become very important raw material for the industrialized production of Diosgenin. Diosgenin is the ideal precursor for the synthesis of several steroid hormones and contraceptive steroids. The technique currently adopted is natural fermentation and acidolysis with discharge of large amount of acid water which causes serious environmental pollution. In this thesis, a new technique was established to prepare Diosgenin without the discharge of acid water and at the same time high yield could be achieved.The research work is as follows:In part one, new technique was established to prepare Diosgenin from dry Dioscorea zingiberensis after ethanol extraction and purification by the column. Water was replaced by 95% ethanol. Large amount of starch, cellulose and proteins etc. in ethanol extract were separated by the macroporous resin column. All saponins were acidolyzed in ethanol and hydrochloric acid (HCl). Subsequently Diosgenin was obtained after neutralization and recrystal. The yield of Diosgenin was 2.76% which was 3.88 times of 0.71% obtained by the traditional technique of natural fermentation. The consumption of HCl was greatly reduced with zero discharge of acid water.In part two, the yield of Diosgenin and consumption of HCl were studied when fresh Dioscorea zingiberensis took the place of dry Dioscorea zingiberensis. The yield was 0.83%.44.71 mL of HCl was used to obtain one gram of Diosgenin which was about 3.32 times of that used for dry raw material. Using dry raw material could overcome the disadvantage of seasoning production of the processing enterprises. Compared with fresh Dioscorea zingiberensis, dry Dioscorea zingiberensis had better cost performance.In part three, the yield of Diosgenin and consumption of HCl were compared between the new technique and the direct acidolysis technique. The yield for direct acidolysis was 2.13% and 17.42 mL of HCl was consumed for every gram of Diosgenin, which were closer to those of the new technique. However, the starch and the cellulose in Dioscorea zingiberensis could not be reulitlized.