Preparation And Bioactivity Of Three Kinds Of Wild Boletus Edulis Polysaccharides In Yunnan Province

In this study, crude polysaccharides were isolated from the fruiting bodies of Boletus speciosus Frost, Boletus bicolor Peck and Boletus sinicus W.F.Chiu. The antioxidant activity of crude polysaccharides was evaluated by the scavenging capacities of the hydroxyl.The inhibitory effects of crude polysaccharides on the non-enzymatic glycosylation of proteins were studied by an in vitro model for non-enzymatic glycosylation reaction system consisting of bovine serum albumin and glucose. Also the protective effects of the BSIP80 and BSIP95 on H2O2 induced oxidative stress in HepG2 cells were analyzed. BSIP95 was conducted by further isolation and purification. The main results are as follows:1.The polysaccharides were obtained from processes of extraction by hot water, deproteinization, decoloration and precipitation by 40%,60%,80%,95% ethanol. The monosaccharide compositions of crude polysaccharides were analyzed by HPLC. Results showed that BSPP40, BBIP40 and BSIP95 had the highest yields of polysaccharides and polysaccharide (2.31%,3.31% and 2.51%, respectively). According to the monosaccharide composition analysis, the content of glucose was relatively high in polysaccharides which subsided by 40% and 95% ethanol. The content of galactose was relatively high in BSPP60, BBIP60 and BSIP60. For the polysaccharides subsided by 80% ethanol, the contents of glucose and galactose were significantly higher than other monosaccharides.2. All of the crude polysaccharides from three Boletes had significant effects on scavenging hydroxyl radicals. BSPP80, BBIP95 and BSIP95 exhibited relatively high level of radical-scavenging activities at the same concentration comparaed to other polysaccharides. The values of IC50 for three polysaccharides were 0.47,0.45 and 0.42mg/mL, respecitively. Simulation system of protein non-enzymatic glycation was applied to evaluate antiglycation acitivity of the concentration of lmg/mL BSPP80, BBIP95 and BSIP95 in different stages. The results showed that polysaccharide samples have certain inhibitory effects on the dicarbonyl compounds and advanced glycation end products (AGEs). After 7 days’ incubation, the inhibition rates of BSPP80, BBIP95 and BSIP95 for dicarbonyl compounds were 81.82%,83.30% and 88.82% and the inhibition rates for AGEs were 80.75%、 81.38%、87.75%, respectively.3.The antioxidant activity of BSIP95 was studied by using the H2O2-induced oxidative stress model of HepG2 cells inhanced on the level of cell in virto. The survival rate of oxidatibe damage cell was detected through MTT method. Compared with the blank control group, the treatment of HepG2 cells with BSIP80 and BSIP95 (50,100,200 μg/mL) for 24 h was without significant effect on cell viability. But the polysaccharides exhibited a dose-dependent growth-inhibition activity on HepG2 cells within the range of 0.2-3mg/mL. The results showed that the optimal H2O2 concentration determined was 0.9mmol/L. The BSIP95 can effectively restrain H2O2 induced damage of HepG2 cells, increased SOD activity and inhibit cell apoptosis.4.BSIP95 was separated and purified by DEAE-52 ion-exchange cellulose and SephadexG-100 column chromatography, yielding two main subfractions BSIP95-1b and BSIP95-2b.Lack of absorption at 280nm and 260nm by UV scanning showed that both BSIP95-1b and BSIP95-2b contained no protein and nuclear acid. According to the monosaccharide composition analysis, BSIP95-1b is a heteropolysaccharide with a large number of glucose and a small amount of mannose,glucosamine hydrochloride and arabinose.The monosaccharide composition of BSIP95-2b contain glucose, mannose, glucosamine hydrochloride, galactose, xylose, arabinose. FETR spectra and NMR analysis demonstrated that pyranose ring structure were present in the BSIP95-1b and BSIP95-2b.