Water-soluble polysaccharide from dried Lycium barbarum fruits: Isolation, structural features and antioxidant activity

The purpose of this study was to investigate the protective effect of purified Lycium barbarum polysaccharides (PLBP) against tissue oxidative injury. Lycium barbarum polysaccharides were isolated from dried Lycium barbarum fruit fruits by boiling water. Crude polysaccharides were divided into seven small fractions and one major fraction using DEAE–cellulose column. Major fraction, namely purified Lycium barbarum polysaccharides (PLBP), was analyzed. Results indicated that the average molecular weight of PLBP was 1.21×105Da. The carbohydrate-related absorbances appeared at 3400.38, 2930.49, 1629.66, 1411.40, 1151.44, 1078.24, 1032.50, 920.72, 864.33, 817.08, and 777.04cm−1. Then, strong DPPH radical scavenging activity of PLBP was detected. In addition, after the oral administration of LPBP to animals for 30 days, levels of malondialdehyde (MDA) and antioxidant enzymes activities in skins markedly reduced or increased in aged animals. The results clearly demonstrated that PLBP possessed an antioxidant activity and protective effect against skin oxidative injury.