Comparative study of antioxidant potential in air-dried brown macroalgae of the Canary Islands

For many years, marine macroalgae are known to produce unique molecules with significant potential as natural products. These molecules include bioactive compounds and antioxidants, such as carotenoids, amino acids, proteins, lipids, vitamins, phenols and flavonoids. They have shown promising properties, including anti-coagulant, anti-proliferative, and antimicrobial effects. In this study we analyzed the antioxidant activity of 11 fresh methanolic extracts from marine macroalgae from the Canary Islands. Additionally, the effects of air-drying process in the antioxidant activity were evaluated. Total antioxidant activity methods included DPPH-free radical scavenging activity and ferrous iron chelating activity. Phytoconstituents evaluated were total carotenoids, proline, phenols, flavonoids and condensed tannins. The highest antioxidant activity was detected in the genus Lobophora, which was maintained after the drying process. However, differences were found between the species, with Lobophora dagamae presenting the highest activity. This high activity was consistent with the phenolic compounds analyzed. However, the highest ferrous iron chelating activity was obtained from Dictyota implexa and 3 Sargassum species, as well as in total carotenoids was Sargassum aff. polyceratium. This is the first record of the antioxidant activity to this species, revealing high potential for application in different industries, especially those that maintain this activity after drying process.