Production and in vitro antioxidant activity of exopolysaccharide by a mutant, Cordyceps militaris SU5-08

Cordyceps militaris SU5-08 was derived from an initial strain (C. militaris SU5) by ultraviolet mutagenesis of protoplasts, and the extraction parameters for C. militaris SU5-08 exopolysaccharide (EPS) produced during submerged culture were optimized. The extraction rate of EPS was 1919.16 +/- 165.27 mg/l, which was 120.38 +/- 11.36% higher than that of C. militaris SU5. The in vitro scavenging effects of EPS of C. militaris SU5-08 on hydroxyl, superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals at a dosage of 5 g/l were 63.64 +/- 3.52%, 75.27 +/- 5.16%, and 6.46 +/- 5.03%, respectively. The reducing power of EPS of C militaris SU5-08 was 0.21 +/- 0.01. The results suggest that the EPS of C. militaris SU5-08 can be used as a potential antioxidant which enhances adaptive immune responses. (c) 2012 Elsevier B.V. All rights reserved.