Phlorotannins extracted from macroalgae as a new antioxidant source

Industrial usage of different macroalgae has grown exponentially during the last decade. Nutritional applications for human feeding and multiple therapeutic are their main important exploitation. This study aimed to investigate the biological activities of the organic, water and ethyl acetate fractions of two brown algae Polycladia myrica and Padina sp., collected from the coast of Qeshm Island. In this experimental study, for identification of the superior species, the tested biological activities included antioxidant assay at gradient concentrations by ferric reducing power assay, FRAP, inhibition free radicals DPPH and ABTS, total phenolic and phlorotannins content, and antibacterial assay by disk diffusion. The more effective algal fractions by maximum antioxidant capacity in all tested methods were recorded for ethyl acetate fractions in both macroalgae. Only ethyl acetate fraction of Padina sp. had an antibacterial effect on all studied strains. Both brown algae, Polycladia myrica and Padina sp., had antioxidant and antibacterial activities, but Padina sp. due to the high amount of phenol and phlorotannins and high antioxidant and antibacterial power can be introduced as a priority species for biological properties.