Extraction Optimization And Structural Characterization,Antioxidant Activities Of Polysaccharide From Morchella Sextelata

Morchella sextelata M.Kuo belongs to Ascomycota,Discomycetes,Pezizales,Morchellaceae,Morchella Dill.Ex Pers.It is a kind of precious,nutritious and delicious edible and medicinal fungi with important economic and medicinal value.Polysaccharide is an important active ingredient of Morchella,which has many pharmacological effects,such as immunomodulatory,antioxidant and anti-tumor.In this experiment,M.sextelata was used as the material to optimize its polysaccharide extraction process,to clarify its physicochemical properties,and to detect its antioxidant ability.It provides a research basis for the development and utilization of M.sextelata in antioxidants and functional foods.Firstly,the experimental materials were identified as M.sextelata based on morphology and molecular phylogeny.Secondly,the extraction process of M.sextelata polysaccharide was optimized by single factor test combined with response surface analysis,and the results showed that the optimum extraction conditions were:extraction temperature 89.94?,liquid material ratio 31.07:1 mL/g,extraction time 162.86 min.Under this condition,the yield of polysaccharide was 23.98%,and the verification results were 23.4%,which is consistent with it.Therefore,it is concluded that the response surface optimization method can be applied to design the extraction condition of polysaccharide from M.sextelata fruiting body.Thirdly,the protein,pigment and small molecular substances in crude polysaccharide of Morchella were removed by Sevage method and dialysis method,and the polysaccharide MSP was further purified by DEAE FF ion exchange column and Sephacry S-400 HR gel column chromatography.The physical and chemical properties of MSP2-1 are analyzed by adopted gel permeation chromatography-refractive index-multi angle laser light scattering(GPC-RI-MALLS),high performance an ion exchange chromatography(HPAEC),fourier transform infrared spectrometer(FTIR)and gas chromatography-mass spectrometry(GC-MS).The results showed that the content of polysaccharide was 75.6%,the content of glycolic formaldehyde was 14.5%and the protein content was 7.6%in MSP2-1.The molecular weight of the polysaccharide was 3.178�104 Da,and its composition was mannose(75.6%),glucose(8.28%),galactose(2.62%),glucose acetaldehyde(2.29%),fructose(0.59%),ribose(0.31%),arabinose(0.21%)and fucoidan(0.10%).The results of infrared spectroscopy further prove that MSP2-1 is a polysaccharide substance.The results of methylation analysis showed that there were 7 glycoside bonds in MSP2-1,with a maximum molar percentage of 1,6-Man,up to 30.07%,followed by 1,2-Man,T-Glc,T-man,1,4-Man,1,2,6-Gal and 1,4,6-Man,The molar percentages respectively were 19.47%,15.62%,11.38%,8.29%,8.21%and 6.96%.Finally,the abiligy of radical-scavenging of MSP and MSP2-1 were examined respectively to 2,2-azino bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS,1,1-diphenyl-2-picrylhydrazyl(DPPH),hydroxyl free radicals and superoxide anion free.The results showed that the clearance rate of MSP and MSP2-1 to ABTS reached 99%.when the concentration reached 0.4 mg/mL,and when the concentration of polysaccharide reached 2 mg/mL,the clearance rate of MSP and MSP2-1 to DPPH reached 93.9%and 100%,and the clearance rate of hydroxyl radicals respectively was 70.3%and 70.11%.The above results show that the polysaccharide of M.sextelata has strong antioxidant ability in vitro.