Extraction Optimization,Structural Characterization And Biological Activity Of Polysaccharide From Trametes Suaveolens

Trametes suaveolens belongs to Basidiomycota,Agaricomycetes,Polyporales,Polyporaceae,Trametes,is a medicinal fungus,widely distributed in all provinces of China.Polysaccharide is an important active ingredient in the medicinal fungus,which has anti-tumor,antifungal,antioxidant effects.At present,studies on the extraction process,physicochemical properties and biological activity of T.suaveolens polysaccharides have not yet been reported.In this study,the extraction process of T.suaveolens substrate polysaccharide was optimized,the active polysaccharide fraction of T.suaveolens was obtained by chromatography,its physicochemical properties were initially clarified,and the in vitro antioxidant activity and antibacterial activity of the polysaccharide were determined.Details of the study are as follows:（1）Morphological and molecular biological methods were used to identify the test material purchased from Delai agricultural specialties store in Huadian,Jilin City,Jilin Province,and the purchased sample was identified as T.suaveolens.（2）Based on the single-factor test,Box-Behnken response surface analysis was used to optimize the polysaccharide extraction process of T.suaveolens substrates,and the multiple quadratic regression equation with polysaccharide yield as the objective function was obtained:Y=10.626+0.3525A+0.19625B+0.00875C+0.26AB-0.595AC+0.3075BC-1.6325A²-1.90175B²-1.26175C².The best extraction conditions were obtained by regression analysis of the mathematical model:liquid to material ratio of 29.83 m L·g^-1,extraction time of 243.52 min,extraction temperature of 81.16℃.The expected polysaccharide yield under this condition was10.65%,which was verified to be 10.34%,which was a good fit and suitable for T.suaveolens polysaccharide extraction study.Under the above optimal extraction process conditions,the crude polysaccharide obtained by hot water extraction was named as CTSP（Crude Trametes suaveolens polysaccharide）.（3）After removing the protein,small molecules and inorganic salt impurities from CTSP by dialysis,the preliminary purified polysaccharide TSP（Trametes suaveolens polysaccharide）was obtained by DEAE-cellulose anion exchange chromatography and Sephadex G-100 The polysaccharide fraction TSP2-1 was obtained by DEAE-cellulose anion exchange chromatography and Sephadex G-100 dextran gel column chromatography,and the polysaccharide content was 68.82%by phenol-sulfuric acid method.The monosaccharide composition and relative molecular weight of TSP2-1 were determined,and the results showed that the molecular weight of the polysaccharide was 2.9×10⁶Da,the glyoxylate content was0.03%,and there were eight monosaccharide fractions,namely glucose（75.55%）,galactose（13.00%）,mannose（5.83%）,fucose（4.37%）,xylose（0.53%）,rhamnose（0.40%）,arabinose（0.28%）,and ribose（0.03%）,indicating that TSP2-1 is a heteropolysaccharide.The results of infrared spectroscopy showed that TSP2-1 has a pyran ring structure.（4）TSP2-1 was tested for its ability to scavenge ABTS radicals with kit,DPPH radicals,hydroxyl radicals and superoxide radicals.The results showed that the scavenging ability of TSP2-1 on ABTS radicals and hydroxyl radicals was strong and showed a concentration-dependent effect.At the concentration of 5 mg·m L^-1,the scavenging rates of hydroxyl radicals and ABTS radicals reached 84.02%and 62.14%,and the scavenging rates of DPPH radicals and superoxide radicals were 31.43%and 37.22%,respectively,indicating that TSP2-1 has strong in vitro antioxidant activity.（5）The mycelial growth rate method was used to determine the inhibitory activity of TSP against Fulvia fulva,Fusarium verticillioides,Curvularia lunata,Fusarium graminearum and Monilinia fructigena.The results showed that TSP was most effective in inhibiting F.fulva,with the highest inhibition rate at a polysaccharide concentration of 10 mg·m L^-1,the highest inhibition rate was 33.42±4.20%;Further determination of the inhibitory activity of TSP against F.fulva was obtained from the virulence regression equation Y=3.4645x+0.4845,and the medium inhibition concentration was 14.29 mg·m L^-1.The results of this study indicate that T.suaveolens polysaccharide has antioxidant activity and some inhibitory activity against phytopathogenic fungi,and has potential exploitation value.