Studies On Purification,Structure And Biological Activities Of Polysaccharides From Oudemansiella Radicata And Russula Vinosa

Many kinds of mushrooms are delicious and edible,and at the same time possess valuable tonic and medicinal attributes.According to previous reports,natural polysaccharides from mushrooms manifest a diversity of biological properties,including antioxidant,antitumor,immunomodulatory,antihyperglycemic,antihypercholesterolemic and hepatoprotective activities.These activities endow fungal polysaccharides with a tremendous potential as a source of medicine and functional food.In this study,the water-soluble and alkali-soluble polysaccharides from the mushroom Oudemansiella radicata and Russula vinosa(named ORWP,ORAP,RVLWP and RVLAP,respectively)were isolated and purified by employing a procedure involving ethanol precipitation,dialysis,anion-exchange and gel filtration chromatography.Then,the structure and biological activities of these polysaccharides were investigated.The average molecular weight(Mw),number average molecular weight(Mn)and D value(Mw/Mn)of ORWP determined by HP-GPC were 12.1 kDa,9.03 kDa and 1.34,respectively.The Mw,Mn and D value of ORAP were 11.5 kDa,8.94 kDa and 1.29,respectively.ORWP and ORAP were composed of ribose:rhamnose:arabinose:xylose:mannose:glucose:galactose at the molar ratios of 0.15:0.32:1.02:2.45:15.74:65.85:14.47 and 0.16:0.51:1.02:3.31:18.41:72.35:4.24,respectively.The monosaccharide composition of ORWP was identical to that of ORAP,while the molar ratio shows much difference.Infrared spectrum analysis indicated that ORWP and ORAP have a typical ?-pyranoid form of polysaccharide structure.Regarding the antioxidant activities,ORWP and ORAP showed effective DPPH radical scavenging activity,hydrogen peroxide scavenging activity and lipid peroxidation inhibitory effect,and moderate reducing power and Fe2+ chelating activity.For the hepatoprotective activity,administration of ORWP and ORAP prevented the increase in serum alanine aminotransferase(ALT)and aspartate aminotransferase activities(AST)in carbon tetrachloride(CCl4)-induced acute liver damage,suppressed hepatic malondialdehyde(MDA)formation and elevated activities of hepatic superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px).Thus,we speculate that ORWP and ORAP protect the liver from CCl4-induced hepatic damage via antioxidant mechanisms.The growth inhibitory effects of ORWP and ORAP against Sarcoma 180(S180)tumor cells in vitro were examined.At 500 ?g/mL,the inhibition ratios of ORWP and ORAP were lower than 10%,which indicated that ORWP and ORAP exhibited indirect cytotoxic activity against tumor cells.While the growth of S180 tumor in mice was inhibited when mice was fed by ORWP/ORAP.In addition,ORWP and ORAP could not only improve the weight of the immune organs in tumor-bearing mice,but also remarkably enhance IL-2 and IFN-? production and reduce IL-10 expression.The results indicated that antitumor properties of polysaccharides from Oudemansiella radicata might be achieved by boosting the immune response.The HP-GPC analysis showed that the Mw,Mn and D value of RVLWP were 12.9 kDa,9.20 kDa and 1.40,respectively.It was composed of rhamnose:arabinose:xylose:mannose:glucose:galactose in a molar ratio of 0.28:0.91:1.71:12.50:67.77:16.80.Infrared spectrum analysis indicated that RVLWP has a typical ?-pyranoid form of polysaccharide structure.While,the Mw,Mn and D value of RVLAP were determined to be 4.00 kDa,3.27 kDa and 1.22,respectively.Monosaccharide composition analysis indicated that RVLAP was made up of ribose:rhamnose:arabinose:xylose:mannose:glucose:galactose,with a molar ratio of 0.30:0.79:2.70:4.54:29.07:57.79:4.81.The absorption band at around 840 cm-1 in the FT-IR spectra indicated that a-glycosidic bonds were present in RVLAP.For the in vitro antioxidant activities,RVLWP and RVLAP showed effective DPPH radical scavenging activity,hydrogen peroxide scavenging activity,lipid peroxidation inhibitory effect,Fe2+ chelating activity and moderate reducing power.Ascorbic acid was employed as the standard antioxidant in the present study.For the in vivo hepatoprotective activity,administration of RVLWP and RVLAP significantly prevented the increase in serum ALT and AST activities in acute liver damage induced by CCl4,suppressed hepatic MDA formation.Mice treated with RVLWP and RVLAP showed a better profile of antioxidant system with augmented activities of SOD and GSH-Px in the liver.The antitumor and immunomodulatory activities of RVLWP and RVLAP were evaluated in S180 tumor-bearing mice by oral administration.The results indicated that RVLWP/RVLAP exhibited significant antitumor activitin vivo,and a synergistic antitumor effect of RVLWP/RVLAP was also observed when they were combined with CTX to treat the mice.Moreover,oral administration of RVLWP/RVLAP could obviously increase the thymus and spleen indices,the levels of IL-2 and IFN-? and decrease the production of serum IL-10 in S180-bearing mice.And,the results indicated that RVLWP/RVLAP could reverse the immunosuppression in CTX-treated mice to some extent.