Abstract

The aim of this study was to investigate the antibacterial and antifungal activities in some marine organisms from the Red Sea and Suez Canal area. Samples were collected, extracted and dried following a standard method. The obtained crude extracts were tested against two bacterial species (Staphylococcus aureus and Escherichia coli) and one fungus Candida albicans using two assay methods. The disk diffusion assay was used to screen for the presence of antimicrobial agents in the extracts through observing the inhibition zone of growth. The efficiency of the active extracts was determined using the microdilution assay. Out of the eight extracts, only one the soft coral Sarcophyton glaucum showed antibacterial effect. On the other hand, extracts of the soft coral Sarcophyton glaucum and the cucumber Bohadschia graeffei exhibited antifungal activities. Interestingly the extract of the sea cucumber Bohadschia graeff showed strong antifungal activity with LC50=67µg/ml and minimum inhibition concentration (MIC) in the range of 75-100 µg/ml. Results suggested that the Red Sea soft corals and sea cucumbers are a potential natural source for biomedical compounds.

Key words: Marine extracts, Secondary metabolites, microbial activities