Antioxidant properties of a sulfated polysaccharide isolated from an enzymatic digest of Sargassum thunbergii.

The protective effect of sulfated polysaccharides (PS-4) isolated from Sargassum thunbergii against oxidative stress in cells and zebrafish was investigated. To begin, a variety of enzymatic extraction methods were used, including five carbohydrases and four proteases. Among the enzymatic extracts, the S. thunbergii Celluclast-assisted extract (STC) demonstrated the strongest scavenging activities against hydrogen peroxide (H2O2). Five polysaccharide fraction (PS-1 to 5) were isolated from STC and purified using ion exchange column chromatography. The antioxidant activity of these fractions was then assessed. PS-4 demonstrated the most promising free radical scavenging and antioxidant activity. PS-4 had a higher content of sulfated polysaccharide than STC. Thus, increasing the proportion of sulfated polysaccharides may be attributed to protection against H2O2-mediated cell damage and oxidative stress in cell lines and in zebrafish. These results suggest that PS-4 could be a potent antioxidant agent in functional foods and cosmetics.