Comparison of antibacterial activities of Ircinia mutans extracts in two different seasons from Kish Island, Persian Gulf, Iran

Sponges, which constitute the phylum Porifera, are the most primitive of the multicellular animals, among all marine organisms screened. Marine sponges produce the largest number of structurally diversified natural products. In this study we investigated in vitro antimicrobial activity of Ircinia mutans collected from the Kish Island in the Persian Gulf against strains of bacteria Escherichia coli (ATCC 15224), Pseudomonas aeruginosa (ATCC 25619), Staphylococcus aureus (ATCC 1764), and Bacillus subtilis spizizenii (ATCC 6633). Diethyl etter, methanol and aqueous extracts of sponge were evaluated by using the Bacterial Broth Dilution Method. The results showed that the aqueous extracts didn’t have any antibacterial activity. Minimum Inhibitory Concentrations (MIC) of the winter diethyl etter extract was 2 mg/ml for E.coli and 20 mg/ml for P. aeruginosa, whereas the summer diethyl etter extract and both of methanol extracts did not show any activity. The MIC and MBC (Minimum Bacterial Concentration) of summer diethyl etter extracts were 2 mg/ml and 3mg/ml against S.aureus; and 5mg/ml and 10mg/ml when tested on B. subtilis. The MIC and MBC of winter diethyl etter extracts were measured as 1.5 mg/ml and 2mg/ml against S. aurous; and 5mg/ml and 10mg/ml when examined on B.subtilis. Summer and winter methanol and aqueous extracts of I.mutans did not show any activity against these bacteria. Therefore secondary metabolite solutions in diethyl etter contain components with antibacterial properties and can be used as antibiotics products.