| The Pleurotus ostreatus is a main kind of edible fungi in China.The Pleurotus ostreatus can be used as medicine and food because of its rich nutrition,good taste and the health effect.Pleurotus ostreatus polysaccharide(POP)is an important composition of pleurotus ostreatus.Nowadays,more attention is payed to POP by researchers because of its good biological function,such as the improvement of antioxidant activity,anti-inflammatory activity and antihyperlipdemic effect etc.In this paper,the extraction,purification,structure characterization and immune regulation activity of POP were explored.The main experimental contents and results are as follows:(1)The technology of mixed level uniform design was used to optimize the extraction process of Polysaccharide from Pleurotus ostreatus by ultrasound.Based on the results of the mixed uniform test and the practical feasibility,the optimum extraction parameters were determined by repeated test,the results are as follow:the ultrasonic power 120 W,extraction temperature 25?,liquid to material 22:1(mL/g),pH 7.5,enzyme amount 0.5%,enzymolysis processing 6 min,ultrasonic processing 69 min.Under the best extraction condition,the yield of POP was(36.71±0.46)%,this method is simple and feasible,the POP yield is high.(2)The crude POP extracted as before was separated and purified.The ethanol was chosen to decolor by soaking the crude POP in it repeatedly,the Sevage method was chosen to remove the protein.Then the method of dialysis was used to remove inorganic salt and other impurities with small molecules.Then the POP treated as above was separated and purified by DEAE-cellulose-52 ion exchange column chromatography and Sephadex G-100 column chromatography.Finally,three pure constituents were obtained and named POP-?,POP-?,POP-?,respectively.The sugar content of POP-?,POP-? and POP-? were 93.96%,90.00%and 83.63%,respectively.(3)POP-? was chosen to perform the preliminary study of the structure characterization for its high content among POP-?,POP-? and POP-?.The Congo-red reaction and I2-KI reaction indicated that no triple helix structure was occurred in POP-?molecule,with some side chain and branch chain.The result of ?-elimination reaction and scanning spectrometer of UV indicated that the chain of polysaccharides and protein were connected by O-linked covalent bond,and the high content sugar and the infinitesimal protein was contained in POP-?.The effects of temperature,pH,metal ions and complexes on the structure of POP-? were studied.The results showed that POP-?mainly in disordered structure,POP-? can react with ?-elimination in alkaline environment,both acid and alkali can change the conformation of POP-?.POP-? and Ca2+,Congo red and boric acid can react with each other,and the complexing ability of Ca2+ is the strongest.HPLC analysis showed that the relative molecular mass of POP-?was 48456.61.The results of GC-MS showed that POP-? was mainly composed of Rha,GlcUA,Man,Glc and Gal,and the molar ratio of the monosaccharides was 12.66:9.68:8.58:13.03:11.91.(4)The result of animal experiment showed that the preventive intervention of POP could improve the immunity and the antioxidant activity of the immunocompromised mice.The specific performance was as following:? Preventive intervention of POP can alleviate the decrease of Ig-M,Ig-G,Ig-A,IL-2,TNF-a,and INF-? caused by cyclophosphamide,which can improve the body's ability to neutralize toxins,activate the complement,promote the body to activate macrophages,inhibit viral replication,thereby enhancing immunity.? At the same time POP can significantly enhance the spleen T lymphocyte proliferation rate,and improve the body's immunity.And which can help the body to remove excessive reactive oxygen species,to protect the integrity of cell membrane structure,protect the liver and decrease the content of MDA increased abnormally,and help the body to keep on dynamic balance of the free base. |
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