Antioxidant activity of Sargassum polycystum (Phaeophyta) and Laurencia obtusa (Rhodophyta) from Seribu Islands

Fresh and dry specimens of Sargassum polycystum and Laurencia obtusa were collected from the Seribu Islands waters, Indonesia, and crude methanol, diethylether and hexane extracts were tested for antioxidant activity using the thiocyanate method. None of the extracts of dry S. polycystum and L. obtusa showed antioxidant activity, but extracts of fresh material did show activity. L. obtusa extracts had higher antioxidant activity than those of S. polycystum. The methanol extract of S. polycystum was more active than the other extracts, and the n-hexane extract of L. obtusa was more active than the diethylether and methanol extracts.