Antimicrobial Activity of the Marine Algal Extracts against Selected Pathogens

The inhibitory effect of Ulva lactuca (Chlorophyta), Dilophus spiralis (Phaeophyta) and Jania rubens (Rhodophyta) marine algae species has been evaluated against 2 Grampositive bacterial (Streptococcus pyogenes and Micrococcus luteus); 2 Gram-negative bacterial (Shigella flexneri and Vibrio cholerae) and 2 fungal (Candida albicans and Aspergillus niger) isolates using aqueous and six organic extracts (methanol, ethanol, chloroform, acetone, ethyl acetate and hexane). Data revealed that the M. luteus bacteria was the most sensitive pathogen by showing the highest zone of inhibitions (ZIs) of 17 mm with the lowest Minimum Inhibitory Concentration (MIC) of 26.7 μgmL and the lowest Minimum Bactericidal Concentration (MBC) of 53.3 μg mL with chloroform D. spiralis extract. Whereas, aqueous extracts were not active against all selected pathogens regardless of the examined algae species. Based upon data presented herein, chloroform D. spiralis extract was the most active against examined pathogens. Thereby, future performance research in D. spiralisis requested due to their high effectiveness as a cheap antimicrobial agent.