Study On Extraction Of Diosgenin Through Stepwise Biocatalysis And Its Clean Process

Natural products are the significant source of new medicine nowadays. The chemical and biological properties of natural products are studied in order to find lead compounds with great prospect, which structure can be modified after separation and purification. It is an important means of developing new medicine.It is a new technology to extract and separate active constituents from natural plants with enzyme catalysis. Cell walls,pectin,starch and others are common impurities in plants, which do harm to the extraction of effective constituents. If proper enzymes are employed to act on natural plants, the impurities above can be decomposed, which is of great advantage to the extraction of effective ones.Dioscorea zingiberensis C. H. Wright, a typical medical plant, was chosen to be studied in the paper. The process conditions of stepwise enzyme catalysis as well as the influence of it on the yield and melting point of diosgenin were studied. Meanwhile, the reuse of waste liquor and residue in production process was discussed. In the paper, comparison of this method and others was also made according to the yield and melting point of product. The mechanism of enzyme catalysis was done some research on here.Cellulase and pectinase compound, amylase and diastatic enzyme were added in order in the method of stepwise enzyme catalysis, and their optimum conditions respectively were: dose 1‰, 1.5‰, 1‰, temperature 50℃, 75℃, 60℃, pH6.0, 5.5, 5.5. The reaction time of cellulase and pectinase compound and diastatic enzyme was 2h and 6h. But that of amylase was determined by color reaction of iodine, which meant end point when iodine didn't turn blue.Glucose could be extracted from waste liquor after treatment of neutralization, decolorization of activated carbon, condensation and crystallization. Coarse fabric of the plant could be made into CMC-an important chemical with wide use, after being alkalified and etherifed.Compared with other methods, it can improve the yield and quality with less energy consumption. 98% diosgenin from plants is extracted. IR spectrum of the product is in accordance with that of the standard, the purity of it is more than 95% according to its HPLC chromatogram, and its melting point is 202~204℃, which reaches the first - grade standard.