Sponges are the simplest multicellular animals that lack defense mechanisms and rely on chemical defense that have been used by mankind to develop antimicrobial drugs against diseases. The present study was designed to demonstrate the antibacterial and antifungal activities of marine spongeDysidea pallescens semipolar and nonpolar extracts. In this study, D. pallescenswere collected from Hengam Island in the Persian Gulf. The extracts were produced by Bligh and Dyer method. Broth Dilution Methods were used to check the antimicrobial activity ofD. pallescens extracts againstEscherichia coli (ATCC 15224),Pseudomonas aeruginosa(ATCC 25619),Staphylococcus aureus aureus (ATCC 1764),Bacillus subtilis pizizenii (ATCC 6633),Candida albicans (ATCC10231) andAspergillus fumigates (PTCC5009). The results showed diethyl ether extract has bactericidal activity againstS. aureus aureus(MBC=10mg/mL) andB. subtilis spizizenii (MBC=20mg/mL).D. pallescens diethyl ether extract showed a very weak antifungal activity but methanol extract showed fungicidal activity againstA. fumigates(MFC=5mg/mL) andC. albicans (MFC=1.5 mg/mL). Therefore nonpolar-semipolar secondary metabolites ofD. pallescens solutions in diethyl ether have shown significant antibacterial activity and polar- secondary metabolites solutions in methanol have shown significant antifungal activity.

Keywords: Antibacterial, Antifungal, Marine sponge, Persian Gulf