Polysaccharides from Turbinaria conoides: Structural features and antioxidant capacity

Since reactive oxygen species (ROS) are involved in initiating and promoting several diseases such as cancer and cardiovascular events, this study was designed to evaluate the antioxidant activity of sulphated polysaccharides purified from Turbinaria conoides. A fucoidan (AF3), one alginic acid (B) and a neutral glucan (C1F2) were isolated. The glucan is made up of β-(1 → 3)-linked glucopyranosyl residues and has a molecular mass of 5 kDa. The alginic acid contains equimolar proportions of guluronic and mannuronic acid residues. The fucoidan is highly branched and has an average molecular mass of 50 kDa. The in vitro antioxidant capacity of the fractions was studied by ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. The fucoidan (AF3) showed the highest potential followed by the alginate (B) and laminaran (C1F2). Taken together, these findings demonstrate that these polysaccharides could be used as natural antioxidants by the food industry.