Antioxidant and free radical scavenging potential of crude sulphated polysaccharides from Turbinaria ornata

Abstract

AbstractThe sulphated polysaccharides from brown algae have been attracting extensive interest due to their numerous biological activities. The present study was designed to evaluate the antioxidant activity and free-radical scavenging capacity of crude sulphated polysaccharides (CSP) from Turbinaria ornata, a marine brown algae. The CSP was extracted from T. ornata using hot water with the yield of 14.31% (w/w). The chemical composition analysis of CSP showed 71.07 ± 4.61 % of total sugar, 1.81 ± 0.035 % total protein, 27 ± 1.49 % sulphate, and 6.16 ± 0.36 % total phenol. The presence of sulphated polysaccharides in the CSP was confirmed by agarose gel electrophoresis. The in vitro antioxidant activity of CSP was evaluated using total antioxidant power assay and ferric reducing antioxidant power assay (FRAP). The results revealed that the total antioxidant capacity of CSP was 22.205 ± 0.875 (equivalent mg of ascorbic acid/g of CSP) and 0.556 ± 0.03 (mM of FeSO4/mg of CSP) FRAP value, respectively. The free-radical scavenging ability of CSP was demonstrated using 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide radical. The capacity of the CSP to scavenge 50% of free radicals was found to be 88.71 ± 1.01, 440.07 ± 4.43 and 352 ± 4.58 μg/mL for ABTS, DPPH and superoxide radical, respectively. These results showed that the CSP from T. ornata possess antioxidant and free-radical scavenging capacity.