Extraction,Antioxidant,and Protective Effects On Alcoholic Hepatocyte Damage Of Polysaccharide From Ischnoderma Resinosum

Ischnoderma resinosum is a fungus of the genus Ischnoderma in the family Polyporaceae.Its taste is delicious and rich in nutritional value,mostly growing on broad-leaved trees,and sparse coniferous trees is one of the common food and medicine mushrooms in China.In order to better develop and utilize the resources of Ischnoderma resinosum,this paper optimizes the extraction technique of Ischnoderma resinosum polysaccharides.The purified polysaccharide was obtained by isolation and purification,and analyzed its structures were,examined its antioxidant activity and investigated its protective effect on alcoholic hepatocyte damage,with the following main findings.1.Using single factor and response surface experiments,the optimal ultrasonicmicrowave synergistic extraction process of polysaccharide from Ischnoderma resinosum was finally determined as the liquid-to-material ratio was 83 m L/g,the ultrasonic power was 260 W,the microwave power was 260 W,and the extraction time was 45 min.Under these conditions,the polysaccharide yield was(7.005 ± 0.381)%,which was in general agreement with the predicted value.2.Comparison of the effects of three different deproteinization methods using polysaccharide retention and protein removal rates as indicators.The papain-Sevag method was found to be the most effective for the deproteinization of the polysaccharides of Ischnoderma resinosum with a protein removal rate of(83.32 ±1.47)% and a polysaccharide retention rate of(94.90 ± 0.89)%.The IRP was subsequently isolated and purified.3.Structural analysis of the IRP.IRP is a single component with molecular weight of 35834 Da;composed of mannose,ribose,rhamnose,glucosamine,glucuronic acid,glucose,galactose,arabinose,L-fucose,with molar percentages of 3.496: 0.303: 0.017:0.056: 0.495: 73.224: 20.018: 0.204: 2.187;has functional group of polysaccharides,a typical polysaccharide;contains no or very small amount of protein and nucleic acid impurities;contains triple helix structure.4.In vitro antioxidant studies on IRP.IRP showed good ability to scavenge hydroxyl,ABTS· and DPPH· radicals in the concentration range of 0.25～8 mg/m L;it exhibited good intracellular antioxidant activity in oxidatively damaged erythrocytes and protected cells from oxidative damage by increasing the activity of intracellular enzymatic antioxidant defense system and the level of the non-enzymatic antioxidant system,thus alleviating AAPH-induced hemolysis.5.The preventive protective effect of IRP on alcoholic hepatocyte injury was investigated.IRP intervention increased the activity of intracellular antioxidant enzymes(SOD,GSH-Px,and CAT),improved GSH content and resistance to superoxide anion radicals,and reduced MDA and ROS content,thus improving the antioxidant protective effect of the organism.IRP downregulated the expression of proinflammatory cytokines(TNF-α,IL-6).Annexin V-FITC/PI double staining showed that IRP inhibited early apoptosis and late apoptosis of cells.Second,the apoptotic morphology of the cells was observed by inverted light microscopy.the intervention of IRP increased the membrane potential of mitochondria.In addition,IRP inhibited ethanol-induced apoptosis from both extrinsic and intrinsic pathways by downregulating the expression of Caspase-3,9,and 8 proteins.