Characterization and antioxidant activity analysis on the crude Hericium erinaceus polysaccharides extracted by different methods

To investigate the effects of various extraction methods on the crude polysaccharides from Hericium erinaceus and their antioxidant activities,three different methods,including hot water extraction,ultrasonic extraction and alkali extraction,were applied to extract polysaccharides from the fruiting body of Hericium erinaceus and three crude polysaccharides( W-HeP,U-HeP and A-HeP,respectively) were obtained.The yield,physicochemical characteristics and antioxidant activity of the three crude polysaccharides were investigated and compared.The results showed that 4.66% of the yield was obtained for A-HeP,while only 3.92% for U-HeP and 3.29% for W-HeP.IR spectrum analysis indicated that the three polysaccharides had typical absorption for pyran glucan and β- glycosidic bond.UV spectrum and β- elimination reaction further demonstrated the existence of protein and O- glycopeptide bond in these three polysaccharides,implying the existence of glycoprotein in these crude polysaccarides.Based on the analysis of the reducing power,scavenging abilities of DPPH,hydroxyl and ABTS~+radicals,all of the three polysaccharides showed certain antioxidant activity,especially A-Hep,which exhibited about 72%( 5 mg / mL) of scavenging effect for DPPH·,75%( 5 mg / mL) for ·OH and 85%( 0.5 mg / mL) for ABTS~+·. These results indicated that the alkali extraction method possessed better extraction effect. Meanwhile,A-HeP had excellent scavenging radicals ability,showing the potential to be a type of natural antioxidant.