Analysis of the antioxidant activity of the exopolysaccharide produced by bacterium TB10

Abstract

Exopolysaccharide (EPS) are a class of functional polysaccharide compounds synthesized by microorganisms, which have a variety of physiological activities such as regulating immunity, antioxidants, lowering blood lipids and glucose and inhibiting tumors, and are widely used in functional food, medical care and agricultural production. Bacterial exopolysaccharide (EPS), as a natural antioxidant, has attracted much attention for its nontoxicity and good biocompatibility. This study focuses on bacteria TB10 as the research object, extracting and purifying its exopolysaccharide through fermentation culture, and systematically evaluating its antioxidant activity in vitro and in vivo. The results of in vitro experiments show that the exopolysaccharide of bacteria TB10 has a significant ability to scavenge ABTS, DPPH, OH-, and O2- free radicals. Among them, the polysaccharide showed good antioxidant effect in the ABTS and superoxide anion systems, and its removal rate could be increased to about 19% when the concentration increased from 0.4 mg/mL to 2 mg/mL. In the DPPH and hydroxyl radical experiments, the antioxidant effect of the polysaccharide was limited, and the removal rate was only higher than 15% when the concentration reached 2 mg/mL, and the removal rate increased slowly after the concentration exceeded 1.6 mg/mL. In vivo experiments using a nematode model further verified the antioxidant effect of the exopolysaccharides of bacteria TB10 in vivo, and found that it can significantly increase the activity of superoxide dismutase (SOD) and catalase (CAT). The experiment shows that the SOD activity and CAT activity of the nematode are dose-dependent with the extracellular polysaccharide concentration of bacteria TB10, and the enzyme activity is higher when the polysaccharide concentration is 200 ug/mL. The comprehensive analysis shows that the exopolysaccharide of bacteria TB10 effectively alleviates oxidative stress by scavenging free radicals and enhancing the activity of antioxidant enzymes, indicating its potential application value in preventing or alleviating degenerative diseases. This study provides experimental evidence for the development of new natural antioxidants based on bacterial exopolysaccharides and theoretical references for their application in functional foods and medicine.