Antioxidant activity of an exopolysaccharide isolated from Lactobacillus plantarum C88

A neutral exopolysaccharide (EPS), designated LPC-1, was isolated from the culture of Lactobacillus plantarum C88 and purified by ion-exchange and gel-permeation chromatography. LPC-1 had an average molecular weight of 1.15 × 106 Da, and it was composed of galactose and glucose with a molar ratio of 1:2. The antioxidant activity of LPC-1 was evaluated with the in vitro scavenging abilities on hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The results indicated that LPC-1 had good scavenging ability on hydroxyl radicals. Furthermore, the protective effect of LPC-1 on H2O2-induced Caco-2 cells oxidative injury was investigated. As results, LPC-1 inhibited the formation of malondialdehyde (MDA) and raised the activities of superoxide dismutase (SOD) and total antioxidant capacities (T-AOC) in a dose-dependent manner. These results demonstrate that the EPS from L. plantarum C88 has antioxidant effects that may involve scavenging of reactive oxygen species (ROS), up-regulation of enzymatic and non-enzymatic antioxidant activities, and reduction of lipid peroxidation.