Enhancing the prebiotic and antioxidant effects of exopolysaccharides derived from Cordyceps militaris by enzyme-digestion

Abstract

Cordyceps militaris is an edible and potentially medicinal mushroom. It contains various biologically active compounds, including exopolysaccharides. In this study, the abilities as antioxidants and prebiotics of exopolysaccharides of C. militaris (CMP) and its low-molecular-weight polysaccharide of CMP (LCMP) obtained using glycoside hydrolase digestion were investigated. CMP and LCMP had obvious DPPH, ABTS, and hydroxyl radical scavenging activities of 13.71%, 38.33% and 23.94%, and 30.36%, 69.32% and 43.82%, respectively, at a concentration of 1 mg/mL. In the gut microbiota consortium, treatment with CMP or LCMP increased Bacteroidetes growth and decreased Firmicutes/Bacteroidetes ratios, compared with the negative or glucose-treated controls. Based on changes in the consortium, the media treated with CMP and LCMP had increases in acetic, lactic, and 2-hydroxyisocaproic acid metabolites. In particular, LCMP-treated media had increases in production of two phenolic acids, benzoic acid and hydrocinnamic acid. Prebiotic activity tests found that CMP and LCMP had growth-promoting activities (mean values 0.34？0.77 and 0.46？0.95, respectively) similar to those of inulin (mean values 0.43？1.11). These results indicated that LCMP was a beneficial antioxidant and an excellent prebiotic that enhanced proliferation of probiotics and phenolic acid abundance. This may provide a basis for the understanding of the effects of prebiotics on health.