Antioxidant activity of three edible seaweeds from two areas in South East Asia

Total phenolic content (TPC) and antioxidant activity (AOA) of 50% aqueous methanol extracts of the marine algae, Padina antillarum, Caulerpa racemosa and Kappaphycus alvarezzi were studied. TPC was measured using Folin-Ciocalteu method while 1, 1diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), ferrous ion chelating (FIC) assay and beta carotene bleaching (BCB) assay were used to study their AOA. P. antillarum was found to have the highest TPC, 2430 +/- 208 mg gallic acid equivalents (GAE) per 100 g dried sample and ascorbic acid equivalent antioxidant capacity (AEAC), 1140 +/- 85 mg AA/100 g. C. racemosa and K alvarezzi displayed lower TPC and AEAC. C. racemosa had 144 +/- 22 mg GAE/100g dried sample of TPC and 14.3 +/- 2.0 mg AA/100g ofAEAC, while K alvarezzi had 115 +/- 35 mg/100g dried sample of TPC and 37.8 +/- 16.8 mg AA/100 g of AEAC. In addition, P. antillarum displayed the highest reducing power, 15.7 +/- 2.6 mg GAE/g and highest chelating ability. C racemosa and K alvarezzi exhibited lower reducing power, 0.737 +/- 0.423 mg GAE/g and 0.561 +/- 0.269 mg GAE/g, and lower chelating ability. However, the AOA of these three seaweeds as assessed by BCB assay were equally high. (c) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.