Isolation,purification And Structural Analysis Of Alkali-soluble Polysaccharides From Flammulina Velutipes

Flammulina velutipes(Flammulina velutipes),also known as hair staphylococcus aureus,under the fungus door,Basidiomycetes subfamily,bacteria,mushroom head,mushroom species,Flammulina velutipes contain very rich nutrients such as vitamins,proteins and amino acids,lipids,inorganic salts and polysaccharides.Polysaccharide as an important active substance of Flammulina velutipes,with anti-cancer,anti-aging and immune function and many other biological activity.At present,the research on polysaccharides of Flammulina velutipes mainly focused on the simple study on the extraction,structure and activity of water-soluble polysaccharides,and lacks systematic research on polysaccharides of Flammulina velutipes,and thus limits the structure-activity relationship of polysaccharides from Flammulina velutipes.In order to understand the composition and structure of Flammulina velutipes polysaccharides,we have designed the research contents of this subject.The results are as follows:The extract was rinsed by 0.5 M sodium hydroxide solution.The extract was lyophilized by dialysis and then lyophilized to obtain water insoluble polysaccharide as brown powder with a yield of 1.48%(relative to Wet weight yield).The total sugar content of AFVP was 89.3%,the uronic acid content was 0.9%,the protein content was 2.2%,and the ash content was 4.73%.The results of monosaccharide composition analysis showed that AFVP was mainly composed of Glc(46.4%)and Man(29.7%),and contained a small amount of Ara(11.5%),Gal(9.7%)and constant Fuc(2.7%).The AFVP was neutralized by DEAE-Cellulose ion exchange chromatography to obtain distilled acid eluted neutral sugar fraction AFVP-N and 0.4 M NaCl eluted acidic sugar fraction AFVP-A,and further by gel chromatography Sepharose CL-6B and Sephdex G-50 to obtain the final homogeneous fractions AFVP-N-a,AFVP-N-b1 and AFVP-A-b1.The results of monosaccharide composition analysis,molecular weight determination,FT-IR,methylation analysis and NMR analysis show that AFVP-N-a is mainly composed of Man and Gal,with a molecular weight of 106 kDa,which is the structure of α-1,3-Manp structure,the non-reducing ends Manp of the β-structure are connected to the C-6 position of the Manp residue,and α-1,6-Galp and α-1,4-Glcp may be interspersed at the main(Table 3-4);AFVP-N-b1 is mainly composed of Galand Glc,in addition to a small amount of Man and Fuc,its molecular weight of 7.7kDa,for the mannose glucan structure,in order to form a complex heteromannans structure α-1,6-linked Gal and β-1,6-Glc are predominant and are branched and substituted at the O-2 position of the partial Gal,and the side chain is present in the form of terminal Man and terminal Fuc,More complex Heterogalactans;and AFVP-A-b1 is a heteroglucans structure consisting of four monosaccharides consisting mainly of Glc,which has a molecular weight of 3.1 kDa and,in addition,29.2% protein,suggesting that it is a proteoglycan structure,Part of the main chain structure with β-1,6-Glcp and part α-1,6-Galp,and partially substituted,where in the O-3 position of the partial Glcp is t-Β-Glcp side chain;there are a small amount of Galp O-2 with t-α-Manp side chain structure,in summary,we speculate that AFVP-A-b1 is Manogalactoglucans structure.