Antimicrobial and antiparasitic activities of three algae from the northwest coast of Algeria

The objective of this study was to investigate the biological activities of Algerian algae, Sargassum vulgare, Cladostephus hirsutus and Rissoella verruculosa. Antimicrobial activity of the crude extracts and their fractions was assessed using the disc diffusion assay, the minimum inhibitory concentration and the minimum bactericidal concentration. Antiparasitic activity was studied in vitro against the blood stream forms of Trypanosoma brucei brucei and the intraerythrocytic stages of Plasmodium falciparum. Ethyl acetate (EA) fractions of the three tested algae showed more potent antimicrobial activity against S. aureus (7–14.5 mm) and B. cereus (7–10.75 mm), MIC values ranged from 0.9375 to 7.5 mg mL⁻¹ and MBC values > 15 mg mL⁻¹. Concerning the antiparasitic activity, EA factions of S. vulgare (IC₅₀ = 9.3 μg mL⁻¹) and R. verruculosa (IC₅₀ = 11.0 μg mL⁻¹) were found to be more effective against T. brucei brucei, whereas the three EA fractions were little active against P. falciparum.