Study On Extraction,Isolation,Structural Characterization And Antioxidant Activities Of Polysaccharides From Ganoderma Lucidum

Ganoderma lucidum is a famous edible and medical fungus.According to ancient medical books,G.lucidum is the king of medicine,which has the effect of calming the mind and relieving cough.The results showed that G.lucidum polysaccharides(GLP)is one of the most important active components,which has the functions of improving organism immunity,antioxidation,anti-aging,anti-tumor and assisting sleep,etc.So,Ganoderma lucidum polysaccharides have great development value.With the development of G.lucidum technology of substitution cultivation,the yield of G.lucidum has been greatly increased.Guanxian County,Shandong Province,is the main cultivation base of G.lucidum in China.The production of G.lucidum reached7,000 tons per year,accounting for more than half of the national Ganoderma market.However,G.lucidum in Guanxian County always had the problem of high quantity and low price.G.lucidum in Guanxian cultivated from xylitol residue was selected as the research object in this study,mainly focused on the extraction,separation,structural characterization and antioxidant activity of GLP from Guanxian.The results in this work would provide theoretical basis for rational development of G.lucidum resources in Guanxian County and help to improve the additional value of products in Guanxian County.The main contents and results in this study are as follows:1.The hot water extraction optimal condition was liquid-solid ratio 40:1 m L/g,extraction time 3 h,alcohol precipitation time 8 h,and the extraction yield of GLP-W was0.63%.By response surface analysis,the optimal extraction process of GLP-(Ch Cl-Urea)was the content of choline chloride-urea 34%,extraction time 1.9 h,alcohol precipitation time 7.3 h,and the extraction yield was 1.10%.The optimal extraction process of GLP-(Ch Cl-Oxa)was the content of choline chloride-oxalic acid was 46%,extraction temperature was 79.7℃,alcohol precipitation time was 12.7 h,and extraction yield was1.02%.2.Three drying methods,hot-air drying,freeze drying and the re-dissolve freeze-drying were compared,according to the physicochemical properties and antioxidant activities of the obtained polysaccharides,the re-dissolve freeze-drying method was regarded as the most suitable drying method for G.lucidum polysaccharides.3.On the basis of GLP-W,ethanol precipitation was performed,it was concluded that GLP80 has the highest content and the best antioxidant activities of G.lucidum polysaccharides in the first ethanol precipitation,GLP80 D has the highest content(59.40%)and GLP80 A has the strongest activities in the second ethanol precipitation.4.According to the structure determination,the polysaccharides obtained in this experiment all contain a small amount of nucleic acid and have typical characteristic absorption peaks of polysaccharides.G.lucidum polysaccharides were β-pyranose and composed by glucose mainly.5.The antioxidation results showed that the orders of DPPH radical scavenging,Hydroxyl radical scavenging activities and reducing power of polysaccharides from different extraction methods were GLP-(Ch Cl-Oxa)>GLP-W>GLP-(Ch Cl-Urea);GLPW>GLP-(Ch Cl-Oxa)>GLP-(Ch Cl-Urea);GLP-(Ch Cl-Oxa)>GLP-(Ch Cl-Urea)>GLP-W.In a word,G.lucidum polysaccharides extracted by DESs can not only improve the yield,but also have notable antioxidant activities,which can provide scientific basis for the extraction and development of natural active components in the future.