title: Antioxidant potential of two red seaweeds from the Brazilian coasts.
abstract: In this work, in vitro antioxidant activity of two Brazilian red seaweeds, Gracilaria birdiae and Gracilaria cornea, was characterized. The total phenolic content, the radical-scavenging activity and the antioxidant activity were determined in two solvent extracts of the algae. Liquid chromatography-mass spectrometry (LC-MS/MS) allowed identification of important antioxidant compounds. The ethanol extract of G. birdiae was found to have the highest value of total phenolic content: 1.13 mg of gallic acid equiv (GAE)/g of extract. The radical-scavenging activity of G. birdiae and G. cornea extracts has been evaluated at different extract concentrations; the IC(50) values of ethanolic extracts of G. cornea and G. birdiae were 0.77 and 0.76 mg mL(-1), respectively, while for methanolic extracts, the IC(50) values of G. cornea and G. birdiae were 0.86 and 0.76 mg mL(-1), respectively. The antioxidant activities of these two seaweeds' extracts as assessed by the β-carotene-linoleic acid assay were equally high, achieving values of β-carotene oxidation inhibition of up to 40%. Finally, in the methanolic extracts, LC-MS/MS allowed identification in both algae of two important antioxidants: apigenin and gallic acid.
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Braga, Portugal.
authors.forename: Bartolomeu W S
authors.initials: BW
authors.lastname: Souza
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Cerqueira
authors.forename: Joana T
authors.initials: JT
authors.lastname: Martins
authors.forename: Mafalda A C
authors.initials: MA
authors.lastname: Quintas
authors.forename: António C S
authors.initials: AC
authors.lastname: Ferreira
authors.forename: José A
authors.initials: JA
authors.lastname: Teixeira
authors.forename: António A
authors.initials: AA
authors.lastname: Vicente
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology; D047310:Apigenin / Q000032:analysis; D001938:Brazil; D016166:Free Radical Scavengers / Q000032:analysis / Q000494:pharmacology; D005707:Gallic Acid / Q000032:analysis; D044724:Gracilaria / Q000737:chemistry*; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D019207:beta Carotene / Q000737:chemistry
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D019207:beta Carotene; D005707:Gallic Acid; D047310:Apigenin