In vitro antioxidant properties of crude extracts and compounds from brown algae

► The major bioactive components in brown algae are concisely summarized. ► The chemical in vitro tests for antioxidant activity applied to brown algae are compiled and comparatively presented. ► The components exclusively present in brown algae are emphasized. ► The potential to protect from oxidation in model and real oily systems is explained. Research on the bioactives from seaweeds has increased in recent years. Antioxidant activity is one of the most studied, due to the interest of these compounds both as preservatives and protectors against oxidation in food and cosmetics and also due to their health implications, mainly in relation to their potential as functional ingredients. Brown algae present higher antioxidant potential in comparison with red and green families and contain compounds not found in terrestrial sources. In vitro antioxidant chemical methods, used as a first approach to evaluate potential agents to protect from lipid oxidation in foods, confirmed that the brown algae crude extracts, fractions and pure components are comparatively similar or superior to synthetic antioxidants. Particular emphasis on the fucoidan and phlorotannin polymeric fractions is given, considering variations associated with the species, collection area, season, and extraction and purification technologies.