In vitro evaluation of antimicrobial activity of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937)

Abstract

The antimicrobial activity of five crude extracts (aqueous, methanol, ethyl acetate, acetone and methylene chloride) of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937) was evaluated in vitro by using microdilution method against eight bacterial and eight fungal strains for the first time. The extracts were proven to be active in varying degrees against all the bacteria and fungi tested. O. rotunda methanol extract exhibited the highest antibacterial activity (minimum inhibitory concentration (MIC) 7.5-15.0 mu g/mL and minimum bactericidal concentration 15-30 mu g/mL), while its acetone extract exhibited the most promising antifungal activity (MIC 7.5-45.0 mu g/mL and minimum fungicidal concentration 15-60 mu g/mL). The extracts were more effective against the bacteria and fungi screened compared with the positive controls (streptomycin and ampicillin for bacteria and bifonazole and ketoconazole for fungi, respectively). According to the experimental data obtained, this deepwater sponge species may be considered as a gold mine of new antimicrobial substances with significant and broad-range activity.