Seaweeds from Mauritius as a source of bioactive compounds

Abstract

Mauritius boasts a highly diverse marine ecosystem, with 435 seaweed species. However, limited research exists on their bioactive potential. This study assessed the antioxidant, anti-Candida albicans, and anti-Staphylococcus aureus activities of four seaweed species: Caulerpa racemosa, Boodlea sp., Chondrus crispus and Padina gymnospora. Specimens were collected on the structures of a marine fish farm and macerated with five solvents: methanol, ethanol, acetone, dichloromethane, and deionized water. Antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl assay, while minimum inhibitory concentrations (MICs) were evaluated using the broth microdilution method. Acetone and methanol yielded the highest extract concentrations (up to 77.7 mg/mL). Antioxidant activity varied significantly by species and solvent, with the strongest activities observed in the acetone extract of Boodlea sp. (ψ̂ =1.55 %; p=0.030) and the methanolic and dichloromethane extracts of P. gymnospora (ψ̂ =44.70% and 23.94 %). All species, except C. racemosa, exhibited antifungal activity, with ethanol and dichloromethane extracts of P. gymnospora the most effective (25 mg/mL and 37.5 mg/mL, respectively). C. crispus showed the highest antibacterial activity, especially in its acetonic extract (MIC = 20.8 mg/mL). Deionized water extracts showed no antimicrobial activity. These results highlight the pharmaceutical potential of Mauritian seaweeds and the need for further bioactivity research.