Exploring the Biotechnological Value of Marine Invertebrates: A Closer Look at the Biochemical and Antioxidant Properties of Sabella spallanzanii and Microcosmus squamiger

and were profiled for proximate composition, minerals, amino acids, fatty acids (FA), carotenoids, radical scavenging activity on the 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical, oxygen radical absorbance capacity (ORAC) and iron and copper chelating properties. had the highest level of moisture and crude protein, was enriched in crude fat and ash. Both species had similar levels of carbohydrates and energy. There was a prevalence of arginine and glycine in , and of taurine in . The most abundant minerals in both species were Na, Ca, and K. The methanol extract of had metal chelating properties towards copper and iron, while the methanol extract of was able to chelate copper. extracts had similar ORAC values. Fucoxanthinol and fucoxanthin were the major carotenoids in the dichloromethane extract. Saturated FA were more abundant than unsaturated ones in methanol extracts, and unsaturated FA prevailed in the dichloromethane extracts. Palmitic acid was the predominant FA in methanol extracts, whereas eicosapentaenoic (EPA) and dihomo-γ-linolenic acids were the major compounds in dichloromethane extracts. Low -6/ -3 ratios were obtained. Our results suggests that both species could be explored as sources of bioactive ingredients with multiple applications.