Bioactivity potential of some marine algae from south of Iran

Algae are composed of a diverse group of various aquatic organisms. Secondary or primary metabolites from these organisms may be potential bioactive compounds of interest for use in the development of new pharmaceutical agents. In this research, four species of marine algae, Ulva lactuca, Padina pavonica, Colpomenia sinuosa and Cystoseira myrica, isolated from Persian Gulf coasts were evaluated for their antimicrobial activities, using disk diffusion and Minimum Inhibitory Concentration assays. Extracts of the algae selected for this study were prepared using methanol, n-hexane and ethyl acetate as solvents. Best results were shown by the ethyl acetate extracts of Ulva lactuca against bacterial strains. Results also indicated that the bacteria were more sensitive against algal extracts than fungi studied. The lowest value for MIC test was belonged to the green alga, Ulva lactuca, in accordance with growth inhibition zone values obtained from disk diffusion assay. Based on present results, gram-positive bacteria were more sensitive to the algal extracts than gram-negative ones.