Exploring the separation, characterization and antioxidant activity of proteins and peptides from selected seagrasses in Palk Bay region of Tamil Nadu in India

In this study, five seagrass species Halodule uninervis, Thalassia hemprichii, Enhalus acoroides, Cymodocea serrulata, and Syringodium isoetifolium collected from the Mandapam coastal region of Rameswaram (Palk Bay region), Tamil Nadu, India, were selected to identify the antioxidant-rich proteins/peptides. The primary objective was to identify the proteins/peptides present in these seagrass filtrates extracted by using four different pH-based buffer extracts and to assess their antioxidant activity. Among the various buffer extracts, 0.1 M Citrate buffer (pH 5.5) exhibited the highest proteins/peptides recovery in all species. Of these, S. isoetifolium showed the highest recovery percentage (20.18 %) in the 10 kDa filtrate. Notably, the 3 kDa filtrate of S. isoetifolium demonstrated the highest antioxidant activity (83 %). The peptides sequences in all five seagrass samples were identified by MALDI - TOF MS analysis, Furthermore, in silico protein-peptide docking studies were conducted to assess the interaction of the identified peptides with key antioxidant-related targets, including superoxide dismutase, xanthine oxidase, inducible nitric oxide synthase, keap 1 protein, and myeloperoxidase. With all these targets, the peptide derived from S. isoetifolium exhibited better binding affinity. This study emphasized that the potential peptides identified from seagrass are the natural antioxidant sources that can be used to treat disorders linked to oxidative stress.