Extraction Optimization Of Polysaccharide By Cordyceps Militaris Mutant And Its Antioxidant Activity

Cordyceps militaris (L. ex Fr) Link, a valuable traditional Chinese herbal tonic, belongs to Ascomycotina,Pyrenomycetes, Sphaeriales,Claviciptiaceae,Cordyceps. It contains several active ingredients such as cordycepin, polysaccharides, proteins, vitamins, trace elements and many other biological active materials, and has a significant effect on stimulating the function of immune system.UV-irradiation spore mutagenesis is one of the effective breeding methods and it has been widely used until now. Edible and pharmaceutical fungal polysaccharides regarded as"biological response modifier"have become the focous of researches in many academic fields because of their special bioactivity.The polysaccharides of C. militaris not only exist in its fruiting bodies, but also in the mycelia and fermentation broth obtained from liquid culture. Liquid cultures have a lot of advantages, especially for mass production, since they allow for the harvesting of mycelia and the relatively easy extraction of useful material from the fermentation broth. The use of liquid cultures also facilitates the release of polysaccharide.The medicinal properties and applications of C. militaris polysaccharides had been realized and attached importance to all over the world by now. In recent years, more and more researches have turned to focus on the extraction and physiological function of the C. militaris polysaccharides at home.The mutant, namely C. militaris SU5-8 was selected by UV mutagenesis according to the content of polysaccharide in submerged culture, and the optimal time of ultraviolet radiation was 120sPlackett-Burman (PB) test and response surface method (RSM) were used to optimize extraction technology of the intracellular polysaccharide (IPS) and extracellula polysaccharides (EPS), and the results are showed as follows: the best conditions for extracting the IPS is ultrasonic processing nummber 60, ultrasonic processing power 545W, ethanol multiple 3.3 and temperature 80℃. Under these conditions, the yield reached to 9.23%. The best conditions for extracting the EPS is pH 7.4, ethanol concentration 95% and ethanol multiple 3.5. Under these conditions, the yield reached to 2.91μg/mL.The effect of EPS on antioxidation capacity of mice was observed by measuring the superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity and the Malondialdehyde (MDA) content. The in vivo results showed that EPS could significantly elevate the activity of SOD activity and GSH-Px activity, and decrease the MDA content in mice blood.Results showed that the polysaccharide of C. militaris had significantly scavenging effects on superoxide anion, hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and high reducing power. The IPS and EPS had better scavenging effects, the scavenging rate was more than 50% of the above three free radicals. On the reducing power, the IPS and EPS had obvious difference.The results suggest that the IPS and EPS of C. militaris SU5-8 had significantly antioxidant activity in vivo and in vitro, which could be used as natural and potential antioxidants.