| Russula virescens is a kind of common edible fungi in Yunnan,which is often used by locals as function food for regulating the liver,eyesight and relieving depression.In this paper,we optimized the hot-water extraction method of polysaccharide from R.virescens.Then,the extracted crude polysaccharides were purified to study their physicochemical properties,structure characterization and biological activites.The main research results are as follws.The response surface model was used to optimize the yield of polysaccharides on the basis of single factor experiment results.The optimized extraction scheme was: extraction temperature: 90 ℃,dilution factor: 30 times,extraction time: 100 min,and the yield was 9.89%.The crude polysaccharide RVP was obtained after the extract was concentrated,alcohol precipitated,decolorized,and deproteinized.RVP was separated and purified by DEAE ion chromatography column,and two homogeneous polysaccharides RVP-Ⅰ,RVP-Ⅱ and one heterogeneous polysaccharide RVP-Ⅲ were obtained.The physicochemical properties showed that the weight average molecular weight Mw of RVP-Ⅰ and RVP-Ⅱ were 14883 Da and 13301 Da.The weight average molecular weight Mw of two components in RVP-Ⅲ were 1330816 Da and 15970 Da.The total cabohydrate contents of RVP-Ⅰ,RVP-Ⅱ,RVP-Ⅲ were 88.47%,87.65%,83.82%;protein contents were 1.87%,2.37%,2.40%;uronic acid contents were 6.72%,7.48%,9.65%,respectively.RVP-Ⅰ,RVP-Ⅱ,RVP-Ⅲ were basically free of starch and nucleic acids.The structural analysis of RVP-Ⅰ and RVP-Ⅱ showed that neither of them contained triple helix structure.Both RVP-Ⅰ and RVP-Ⅱ were mainly composed of fucose,mannose,glucose and galactose,and their molar ratios were 1:2.244:3.796:4.301 and 1:2.493:36.775:4.905,respectively.Combined with monosaccharide composition,periodate oxidation,Smith degradation analysis,methylation analysis,and 1D/2D NMR analysis,it was preliminarily concluded that the main chain of RVP-Ⅰ was mainly composed of 1,6-β-D-Gal,1,2,6-α-D-Man,1,3,6-α-D-Man,the branch chain was composed of t-α-D-Glc,t-α-D-Fuc,1,4-β-D-Gal.The main chain of RVP-Ⅱ was mainly composed of 1,6-α-D-Glc and 1,3,6-α-D-Man,and the branch chain was mainly composed of 1,4-α-D-Man,1,6-β-D-Gal,t-α-D-Glc and t-α-D-Fuc.The polysaccharides from R.virescens had a certain antioxidant effect within the concentration of 0.25-4 mg/m L.The RVP had the highest antioxidant acticity,with a PSC value of 4.85 μmol Vc/g sample and a CAA value of 1.28 μmol QE/g sample.Besides,RVP showed the highest ORAC value and clearance rate of ·OH at 4 mg/m L,which were 0.11 μmol Trolox/m L sample and 92.77% respectively.Moreover,the polysaccharides from R.virescens also had a good hypoglycemic effect in vitro at 0.025-6.4mg/m L.The 6.4 mg/m L RVP-Ⅰ and RVP-II had the highest inhibition rates for α-glucosidase and α-amylase,83.17% and 91.84%,respectively.The inhibitory types of four kinds of polysaccharides on two enzymes were mainly competitive and non-competitive inhibition.RVP,RVP-Ⅰ,RVP-Ⅱ and RVP-Ⅲ showed a concentration-dependent inhibitory effect on Hep G-2,A549,MCF-7 cancer cells within 100-1200 μg/m L,and the RVP-Ⅲ had the best growth inhibition effect on these three kinds of cancer cells.Moreover,RVP,RVP-Ⅰ,RVP-Ⅱ and RVP-Ⅲ had strong immune acticity in 400-1000 μg/m L,and the crude polysaccharide RVP performed best.The RT-PCR results showed that RVP could enhance the immune activity by up-regulating the m RNA expression of IL-1β,IL-6 and TNF-α secreted by macrophages.Among them,RVP had better effect on the gene expression of IL family immune factors. |
PDF Full Text Request