Nutritional composition, protein characterisation, and in vitro antioxidant activity of the marine polychaete Perinereis nuntia (Lamarck, 1818) from the Bay of Bengal

Abstract

The present study explores Perinereis nuntia from the Bay of Bengal Coast, India, for its nutritional quality, ecological significance, and bioactivity. Proximate analysis demonstrated high moisture (88.76 %), protein (54.33 %), and fat/lipid (27.1 %) levels, suggesting its potential as a nutritive aquafeed for broodstock rearing. Elemental analysis highlighted abundant micronutrients, including zinc (463.25 ppm) and iron (447.18 ppm). Heavy metals were detected, with Pb (34.05±7.53 ppm) being the highest, followed by Ni (13.12±0.69 ppm). Cr and Cd were detected at very low levels. Elevated Pb, Ni, Zn, and Fe levels indicate notable bioaccumulation potential, supporting its use as a bioindicator. Protein extraction with RIPA buffer resulted in a low yield (1.47 mg/g tissue), with evidence of aggregation indicated by UV-Vis spectroscopy, Dynamic Light Scattering (DLS), and FTIR analysis. Despite this, the protein extract exhibited notable DPPH radical-scavenging activity (87.65 %) and moderate Fe³⁺ reducing capacity (10.78 %) in the FRAP assay. This indicates that P. nuntia has preliminary antioxidant activity. The results highlight P. nuntia as a promising multidimensional bioresource, serving as a nutrient source and bioindicator with broader bioactive potential. Additional optimisation of protein extraction methods and extensive biosafety analysis are essential for safe and sustainable use.