Extracting Optimization Of Intracellular Se-Polysaccharide From Cordyceps Militaris And Its Antioxidant Activities

Cordyceps militaris is a valuable traditional Chinese herbal tonic,which contains several active ingredients such as cordycepin,polysaccharides, proteins,vitamins,trace elements,and many other biological active materials. It has a significant effect on stimulating the function of immune system.Selenium(Se) is an essential bio-trace element for human,animals and some microorganisms.In human and animal bodies it acts as a component of glutathione peroxidase(GSH-Px) to break chain reaction of lipid peroxidation by catalyzing peroxide decomposition and scavenging some organic hydroperoxides,such as nucleic hydroperoxide and thimine hydroperoxide,et al.,so as to maintain the integrity of structure and function of biomembrane.Response surface method was used to optimize extraction technology of the intracellular Se-polysaccharide,and the results are showed as follows:the best conditions for extracting the intracellular Se-polysaccharide is ultrasonic processing time 15.11min,temperature 59.26℃and pH 7.17.Under these conditions,the yield can be reach to 113.65 mg/g.The stability of Se-polysaccharide was studied,the results showed that intracellular Se-polysaccharide is less stable at high temperatures,and it is easy to hydrolysis in alkaline conditions than in acidic conditions.Through DEAE-Cellulose method two components of Se-polysaccharide were got,named SeP -1 and SeP-2,which contained 2.95μg/g and 9.86μg/g Se,respectively.Through anti-oxidation experiments in vivo and in vitro,after feeding with Se-polysaccharide,the GSH-Px activity and SOD activity in mice blood significantly increased,which reach a peak at the 6^th and 8^th day,respectively. The content of MOD in blood declined greatly.The effect of two kinds of polysaccharides on superoxide anion radical and hydroxyl radical scavenging is very singnificant,and the reducing power of two kinds of polysaccharide is also very strong.According to the antioxidant experiments in vivo and in vitro, we found that both common polysaccharide and Se-polysaccharide have strong antioxidant capacity,which indicates selenium played a significant role in the biological anti-oxiidation.