Extraction Optimization And Component Identification Of Polysaccharides From Cordyceps Militaris Fruiting Bodies

Cordyceps militaris,a valuable fungus used in food and medicine.Because it is similar to the representative pharmacological components of C.sinensis,it has become a good substitute for C.sinensis.The polysaccharides,the main active substance in C.militaris,have extensive physiological activity and medicinal value.In recent years,the research on the relationship between structure-activity and biological activity of polysaccharide has become one of the focuses of scholars.However,the study on the whole system of polysaccharides from C.militaris is not mature.and the extraction process and components are not yet clear.In this study,response surface methodology was used to optimize the hot water extraction process parameters of C.militaris fruiting body polysaccharides,and the antioxidant activity of polysaccharides extracted by the optimal process was studied in vitro.Meanwhile,C.militaris polysaccharides were isolated and purified,and their main components CP0-A and CP1-A were identified.The main conclusions are as follows:(1)Taking C.militaris fruiting body as the research object,on the basis of single factor,by response surface analysis,the optimum technological conditions of hot water extraction of C.militaris fruiting body polysaccharide were obtained as follows: extraction temperature 80°C,extraction time 3.1 h,material-liquid ratio 41:1(m L:g),extraction times 2 times,under this condition,the actual yield of polysaccharide was 6.3328%.The antioxidant activity of polysaccharides extracted from C.militaris fruiting bodies had better DPPH free radical scavenging power(88.9%)and reducing power(1.133)was also relatively high,while hydroxyl radical scavenging power(53.8%)and total antioxidant capacity(0.807)were relatively low.(2)The polysaccharides obtained by hot water extraction method need further purification and component separation to get more pure polysaccharides.By using DEAE-cellulose-52 and Sephacryl S-400,finally obtained the four C.militaris fruiting bodies polysaccharides of CP0-A,CP0-B,CP1-A and CP1-B.(3)The results of structural identification experiments showed that the monosaccharide compositions of CP0-A were similar to CP1-A.They are composition of alpha-L-rhamnose,beta-1,3-D glucan,alpha-galactose and a small amount of mannose.Their molar ratios are 15.95:4.26:9.60:1.22 and19.44:4.82:8.73:0.30,The Mn of CP0-A is 3.057×104 Da,Mw is 4.923×104 Da,and the conformation of samples is flexible and random.The surface of CP0-A is compact and rough,the structure is not strong,and the surface of CP1-A is smooth and flexible.The results of this study will provide references for further research on the relationship between the biological activity and structural effects,immune mechanism and drug development of C.militaris fruiting body polysaccharides.