In vitro and in vivo antioxidant activity of exopolysaccharides from endophytic bacterium Paenibacillus polymyxa EJS-3

The antioxidant activities of exopolysaccharides (EPS) from endophytic bacterium Paenibacillus polymyxa EJS-3 were evaluated by various methods in vitro and in vivo. In antioxidant assays in vitro, both crude EPS and its purified fractions (EPS-1 and EPS-2) were found to have moderate 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, hydrogen peroxide scavenging activity, lipid peroxidation inhibition effect, and strong ferrous ion chelating activity. And the antioxidant activities in vitro of EPS decreased in the order of crude EPS > EPS-2 > EPS-1. In antioxidant assays in vivo, mice were subcutaneously injected with d-galactose (d-Gal) for 6 weeks and administered EPS-1 via gavage simultaneously. As a result, administration of EPS-1 significantly increased the thymus and spleen indices of d-Gal induced aging mice. Moreover, EPS-1 administration significantly enhanced the activities of antioxidant enzymes and total antioxidant capacity and decreased the levels of malondialdehyde in both serums and livers of aging mice. These results suggested that EPS had potent antioxidant activities and could be explored as novel natural antioxidant.