ACTIVITY-GUIDED FRACTIONATION OF GRACILARIA DOMINGENSIS FOR ANTIOXIDANT PROPERTIES

Abstract

This study aims to investigate the antioxidant capacity of Gracilaria domingensis, a red macroalga, which can help in understanding its physiological state under stress and abundance in different ecological settings. The effects of solvent polarity on reducing power, lipid peroxidation inhibition, and metal chelating ability were analyzed to determine the hexane extract's antioxidant capacity. Results showed that the hexane extract had the highest antioxidant capacity, as demonstrated by Ferric Reduction Antioxidant Power (FRAP), metal chelating, and lipid peroxidation inhibition assays. Furthermore, activity-guided fractionation of the hexane extract identified mycosporine-like amino acids (MAAs) as the primary active constituents contributing to the extract's antioxidant activity. The Total Phenolic Content (TPC) assay using Folin–Ciocalteu (FC) revealed that non-phenolic components such as MAAs also influenced the assay's outcomes. Overall, this study highlights the importance of conducting multiple assays to accurately evaluate the antioxidant potential of Gracilaria domingensis and provides valuable insights into the role of MAAs in enhancing the antioxidant activity of the macroalga.