Isolation And Purification Of Polysaccharides From Poria Cocos

In this dissertation,the extraction,separation and purification of soluble polysaccharides from Poria cocos were systematically studied.1 It is the first time to use the hot water as the solvent to extract the polysaccharides from P.cocos power which was defatted with organic solve-nt.And the most rational technology conditions of defatting method were obtained with the aid of orthogonal tests.The ratio of ethanol and diethyl ether in the solvent system was 1 to 9(V/V).The ratio of material weight and solvent volume was 1 to 25(g/ml).And the extraction time was 5 hours.According to the orthogonal tests,the best extraction conditions with hot water were obtained.The crude extract mentioned above was extracted at the temperature of 50’C for 7 hours.And the ratio of material weight and water volume was 1 to 40(g/ml).The yield of total polysaccharides was rised from 3.08%to 4.13%.2 Sevag method and peroxide hydroge oxidation method were carried out to remove the protein and pigments before the purification of crude poysaccharides,respectively.The optimum conditions of Sevag method and peroxide hydroge oxidation method were obtained with the help of orthogon-al tests.The ratio of chloroform and n-butyl alcohol was 2 to 1(V/V).And the ratio of sample and reagent was 1 to 1(V/V).The pH was 5.The deproteiniz-ation rate of the crude poysaccharides was 75.32%.In the peroxide hydroge oxidation experiment,the concentration of hydrogen peroxide in the polysaccarides solution was 1.5%.And the reaction temperature and time were 30℃ and 5 hours,respectively.The decolorizati-on rate of the crude poysaccharides was 63.57%.3 By means of microfiltration and ultrafiltration,three fractions of poly-saccharides named as PCP1,PCP2 and PCP3 were obtained.These fractions were further purified by gel-filteration chromatography(Sephacryl S100-400)and five polysaccharides were obtained named as PCP1-A,PCP1-B,PCP2-A,PCP3-A,and PCP3-B.As no absorption at 260nm and 280 nm in the UV spectra,there were no nucleic acid and protein in these polysacchari-des.PCP-A,PCP2-A and PCP3-B were proved to be the homogenyeous polysaccharide on the basis of single and symmetrical peak in the HPGPC chromatography.