Compared antioxidant activity of six tropical macroalgal species from Trindade, a Brazilian oceanic island

• DOI: 10.22533/at.ed.8133112311124

• Palavras-chave: macroalgas marinhas, ecossistemas remotos, radicais livres, bioatividade

• Keywords: Benthic algae, remote ecosystems, free radicals, bioactivity

• Abstract: Trindade is an oceanic and pristine island located ~1,100 km off the Brazilian coast. Macroalgal assemblages from remote islands are exposed to several abiotic and biotic stressors that may induce synthesis of chemical defense compounds, including antioxidants. Six species of seaweeds from Trindade were analyzed: Palisada flagellifera (Rhodophyta), Chaetomorpha antennina and Cladophoropsis membranacea (Chlorophyta), Canistrocarpus cervicornis, Sargassum vulgare and Dictyopteris delicatula (Phaeophyceae). Antioxidant activity (AA) was evaluated by (1) DPPH free radical sequestration, (2) Folin-Ciocalteu assay, and (3) carotenoid colorimetric assay. The higher AA using DPPH method was detected in filamentous Chlorophyta using both extracts (dichloromethane and methanolic), C. antennina 36.4 ± 3.7% and C. membranacea 39.1 ± 3.9%. Considering phenolic and carotenoids compounds, all seaweed groups showed higher AA using dichloromethane extracts, with maximum concentration in filamentous Chlorophyta (1418 ± 40 μg g-1 EAG).Carotenoids also were higher in Chlorophyta (3.5 to 2.9 ± 0.2 μg g-1). Green filamentous seaweed from Trindade seem to be the most suitable and promising candidates for AA studies in this area. Despite seaweed AA from Trindade are still considered lower compared to species from higher latitudes, these screenings will be useful to fill gaps in comparative ecophysiology of seaweeds from tropical oceanic ecosystems.