RESUMO
CONTEXT: In the search for new sources of safe and inexpensive antioxidants, the leaves of eight species of seagrasses were screened for antioxidant properties. OBJECTIVE: Most of the seagrasses were evaluated for the first time for their antioxidant activities. MATERIALS AND METHODS: Total phenolic content and in vitro antioxidant activity using, 2,2-diphenyl-1-picrylhydrozyl (DPPH) radical scavenging capacity and FRAP assay. RESULTS: The leaves of Halophila stipulacea (Forssk.) Aschers showed high levels of phenols (1.398 ± 0.055 mg GAE/g) and high reducing power (46.289 ± 1.002) in terms of mg GAE/g. Similarly, H. pinifolia exhibited high total antioxidant activity (132.38, 75.027 mg AscAE/g) and a high percentage of DPPH radical scavenging activity (68.14%). The TAA and FRAP assays showed positive and significantly high correlation (R2 = 0.646). The total phenolic content in the seagrass extracts showed a better correlation with reducing power (R2 = 0.597) than the DPPH radical-scavenging activity (R2 = 0.495). DISCUSSION AND CONCLUSIONS: The antioxidant capacities of the seagrasses showed potential rich sources of natural antioxidants. Further studies are necessary for isolation and characterization of the active antioxidant compounds, which can be used to treat various oxidative stress-related diseases.
