Antioxidant activity of brown algae Sargassum vulgar and Sargassum angustrifolum

The study was aimed at evaluating the presence of phenolics compounds and the antioxidant activity (AOA) of an extract of Sargassum vulgar and S. angustrifolum, the brown algae of Persian Gulf. Aqueous extracts obtained after simple water extraction of the dried samples of the algae at room temperature were tested for phenolics using the Folin-Ciocalteu method and the AOA was evaluated by Suppression of hemoglobin-induced linoleic acid peroxidation. The water extracts of the samples of these two algae contained a high yield of total phenols (TP) at about 8.8 mg catechin equivalent (CE/g dry sample). The strong AOA was detected by linoleic acid peroxidation assay and catechin was used as the control. The phenolics fractions appear to be responsible at least in part for the AOA of these algal samples. Further investigations are needed to identify the particular constituent exhibiting this activity. Fluctuating nature of the AOA against concentration of the dried samples were discussed in terms of possible roles of the peroxidases type of the algal enzyme(s) and a kind of polysaccharide cleaving enzyme(s). These enzymes may remain active at least partially during harvesting and sample preparation. Changeable relationship between phenolic compounds and the relevant AOA in soya powder during solid-state fermentation by a food-grade fungus has been reported recently. Feasibility of this novel type of the antioxidant for use as a functional food or in medicine is encouraging.