Degradation And Antitumor Activities Of Low Molecular Weight Polysaccharide From Grifola Frondosa

This paper systematically studied on polysaccharide is extracted by submerged fermentation from the strains of Grifola frondosa. In this paper, the efforts of the nutrition factors and fermentation conditions are studied on the fermentation of Grifola frondosa. After a preliminary optimization, a large number of mycelium are produced and optimized composition of the medium is obtained, glucose 2%, sucrose 2%, peptone 0.6%, soybean oil 0.1%, KH2PO4 0.05%, MgSO4 0.05%, pH6.0.The crude polysaccharide of Grifola frondosa is acquired through hot water extraction, concentrated and 3 times volume of alcohol precipitation extraction. The optimum extraction conditions: extraction temperature 80℃, the ratio of material-water 1:30, extraction time 4h. Then deproteinization by sevag method and impurity removal by grade alcohol precipitation (first-level concentration of alcohol precipitation50%; second-level concentration of alcohol precipitation80%), as a result, the polysaccharides of Grifola frondosa have been purified.After preliminary purified polysaccharide of Grifola frondosa through DEAE-52 ion exchange chromatography, two components PGF-a and PGF-b are produced. After desalting by SephadexG-25 and concentration, eluate is purified by SepheracylS-400 and SepheracylS-200 gel chromatography. Then the molecular weight distribution of PGF-a and PGF-b is analyzed by using GPC. The result show that PGF-a is a kind of mixture with the inhomogeneous relative average molecular weight and PGF-b is a kind of mixture with the homogeneous relative average molecular weight.In this study the method of free radical is used in the degradation of polysaccharides. After the polysaccharide which has been degraded is purified by SephadexG-75 gel chromatography, two components PGF-bⅠand PGF-bⅡare produced. The concentrated dried PGF-bⅠand PGF-bⅡand PGF-b are used in anti-tumor and antioxidant experiments. The results showed that PGF-b, PGF-bⅠand PGF-bⅡshowed some effect in inhibition of tumor. In the comparative test, PGF-bⅡhas stronger ability in tumor inhibition and free radical scavenging than PGF-bⅠ.