UTTAR PRADESH JOURNAL OF ZOOLOGY

Two-thirds of the world is covered by oceans, whose upper layer is inhabited by algae, marine macroalgae, or seaweeds. Plant foods are a rich source of antioxidants. Antioxidants are molecules that fight free radicals and keep an organism free from various diseases. The present study revealed that the invitro antioxidant activity of ethanolic extracts of Centroceras clavulatum (Red), Enteromorpha intestinalis (Green), and Turbinaria ornata (Brown) collected from Mandapam. The extracts showed radical scavenging activity against DPPH, Hydroxyl, Superoxide, ABTS, and reducing power. All the concentrations of extract showed good antioxidant activity and were much higher than that of standard ascorbic acid. The various assays tested their maximum amount was approximately the same.  Seaweed extracts showed an increase with increasing concentration (between 50 to 800 μg/ml) indicating the dose dependency of these algal extracts. It indicates that it could be a potential source of natural antioxidant lead molecules. Depending on the type of extracts and the antioxidant tests, the 50% inhibitory concentration (IC₅₀) ranged from 12.08 to 18.28 mg/ml. This suggests that T. ornata (brown) has the highest antioxidant activity, making it a promising candidate for future research and applications in health and nutrition.  Conversely, E. intestinalis (Green) displayed the least activity among the extracts tested, suggesting that its efficacy may be limited in comparison to the others. Marine algae contain natural pigments in abundant amounts, which could serve as a valuable source of natural antioxidants for potential use in the food industry, as well as in cosmetics and pharmaceuticals.