A comparative antioxidant profiling of brown, red and green Macroalgae from Kollam coast of Kerala

The increasing demand for natural antioxidants has intensified interest in marine macroalgae, which are rich in bioactive metabolites capable of mitigating oxidative stress and associated degenerative disorders. The present study provides a comparative antioxidant profiling of selected brown, red, and green macroalgae collected from the Kollam coast of Kerala. Six commonly occurring species were evaluated: Sargassum wightii and Padina tetrastromatica (brown algae), Gracilaria corticata and Hypnea musciformis (red algae) and Ulva lactuca and Chaetomorpha antennina (green algae).Methanolic extracts of each species were analyzed for extraction yield, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities using DPPH, ABTS and FRAP assays. Results revealed significant variation in antioxidant profiles among the three algal groups. Brown macroalgae, particularly Sargassum wightii, exhibited the highest TPC, TFC, and overall radical scavenging activity, attributed to the presence of phlorotannins and fucoxanthin. Gracilaria corticata and Hypnea musciformis demonstrated moderate antioxidant potential, reflecting their pigment composition and sulfated polysaccharide content.

Green algae, especially Ulva lactuca, showed comparatively lower but notable antioxidant activity, supported by chlorophyll derived compounds and ulvan.

Overall, brown algae displayed superior antioxidant efficiency, followed by red and green taxa. The findings highlight the Kollam coast as a valuable source of natural antioxidants and support the potential application of these seaweeds in nutraceuticals, functional foods, and marine derived therapeutic formulations.