A Chemical Investigation of the Antioxidant Capacity of Extracts from Red Macroalga Gracilaria domingensis

Extracts that were obtained with solvents of increasing polarity (hexane, dichloromethane, methanol, 80% and water) from the red macroalga Gracilaria domingensis evaluated by reducing power ferric reduction antioxidant (FRAP) Folin–Ciocalteu (FC) assays, lipid peroxidation inhibition β-carotene-linoleic acid assay, metal chelating ability based on iron-ferrozine system. The highest capacity was reported for hexane (Hx) extract FRAP, chelating, assays. An activity-guided fractionation Hx carried out identification its active constituents. primary components most compounds. Despite high activities, not in FC assay. In this activities found methanol (M) (80M) extracts. assay is commonly used to measure total phenolic However, no compounds detected GC-MS HPLC analyses M 80M Thus, non-phenolic influenced extracts showed content mycosporine-like amino acids (MAAs). A fraction contained two MAAs (porphyra-334 shinorine) (156 mg GAE·g−1) a similar performance values well-known antioxidants (BHT = 156 GAE·g−1 Trolox 166 30 times higher than those original (~5 contribute observed within studied samples. Together, these results advance our understanding properties algal