Antibacterial and antioxidant properties of selected fish species in Mauritius

Marine fishes contain bioactive compounds with potential nutraceutical properties. This study investigated the antibacterial and antioxidant properties of five fish species from Mauritius: Acanthurus mata, Scomberoides lysan, Gymnocranius grandoculis, Mulloidichthys vanicolensis and Epinephelus macrospilos. Bioactive compounds were extracted by maceration in methanol, dichloromethane (DCM), and ethyl acetate, followed by pressure evaporation. Antibacterial activity was assessed using agar disc diffusion and minimum inhibitory concentration (MIC) against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. The DCM extract of E. macrospilos yielded the highest inhibition zone (13.8 ± 7.9 mm) against S. aureus, though lower than positive controls (chloramphenicol: 25.4 ± 3.1 mm; ampicillin: 36.8 ± 3.6 mm). The methanol extract of G. grandoculis was the least sensitive of all the extracts (1.7 ± 3.0 mm) against P. aeruginosa. The DCM extract (0.26 mg/ml) from A. mata yielded the most effective MIC against S. aureus. Antioxidant activity, determined with the 2,2-diphenyl-1-picrylhydrazyl radical assay, was highest in the methanol extract of G. grandoculis (IC50: 47.0 mg/ml), but lowest in its DCM extract (94.9 mg/mL). Terpenoids and coumarins were detected, potentially contributing to these bioactivities. The pharmaceutical potential of the studied fishes and their relevance for future drug development research are highlighted.