Isolation,Purification,structural Characterization And Functional Activity Of Hericium Erinaceus Polysaccharide

Hericium erinaceus belongs to the genus Hericium.To date,a couple of Hericium erinaceus polysaccharides have been purified and studied,but little attention is devoted to their deproteinization method,chemical structures and the inhibitory effect on hyaluronidase.In this study,ultrasonic extraction method was optimized to extract Hericium erinaceus polysaccharides(HEP)and deproteinization of HEP with chitosan was studied.The chemical structures of HEP were characterized.The inhibitory effect of HEP against hyaluronidase and its mechanism were also studied.The conclusions of the study are as follows:(1)Based on the single factor tests,the response surface method was used to optimize the ultrasonic extraction method of HEP.The optimum conditions were: the ultrasonic power of 300 W,ratio of material to liquid of 1:27,ultrasonic time of 48 min,ultrasonic temperature of 90 ?.Under such conditions,the yield of HEP was about 8.03 ± 0.46%.And the orthogonal method was used to optimize the hot water extraction method.The optimum extraction conditions were: the extraction temperature of 85 ?,ratio of material to liquid of 1:15,extraction time of 5 h,repeat times of 3 times.Under such conditions,the yield of HEP was about 8.84 ± 0.07%.Therefore,the ultrasonic extraction method can effectively shorten the extraction time(2)The deproteinization of HEP with chitosan was studied.The optimum conditions were: the ratio of material to liquid of 50:1,native pH,precipitation at 4 ? of 2 h.Under such conditions,the removal rate of protein reached about 60.11 ± 0.47%,higher than Sevage method by 11.67%.Meanwhile the loss rate of polysaccharides was decreased to about 11.16 ± 0.48%,lower than Sevage method by 80.87%.And the residual of chitosan was detected about 1.01 ± 0.005%.(3)The crude HEP was purified by DEAE Sepharose Fast Flow column chromatography.Two kinds of HEP,named HEP-?and HEP-? were observed,and the molecular weights were 1.72×104 Da and 1.03×104 Da,respectively.The comprehensive results from Infrared spectroscopy,monosaccharide composition,periodic acid oxidation,Smith degradation and nuclear magnetic resonance analysis showed that the main chain of HEP-?was composed of ?,?-glucose residues and ?-galactose residues,with the side chains composing ?-rhamnose residues and ?-fucose residues,which were linked to the C-4 of ?-glucose residues.And the main chain of HEP-? was composed of ?-glucose residues and ?,?-galactose residues,with the side chains composing ?-galactose residues,?-rhamnose residues and ?-fucose residues,which were linked to the C-6 of the ?-glucose residue.X-ray diffraction,thermogravimetric analysis and Congo-red analysis showed that both HEP-?and HEP-? belonged to amorphous structures,had two weightless platforms and showed no three-helix conformation.(4)Both HEP-I and HEP-? were found to have the inhibitory effect on hyaluronidase with the irreversible type of inhibition.The results of Circular dichroism spectroscopy showed that HEP-? inhibited hyaluronidase by modifying the overall structures of hyaluronidase,while HEP-?inhibited hyaluronidase by mainly modifying the ?-helix content of hyaluronidase.The change in the intensity of the fluorescence emission peak also proved that both HEP-? and HEP-?interacted with hyaluronidase.