A new 9,11-secosterol with a 1,4-quinone from a Korean marine sponge Ircinia sp

An intensive investigation of chemical components for Ircinia sp. led to the isolation of a new 9,11-secosterol. The chemical structure of this compound was elucidated based on the interpretation of NMR and MS spectroscopic data. The isolated compound exhibited antibacterial activities against Staphylococcus epidermidis and Bacillus subtilis with MIC values of 6.3 and 25 μg ml(-1), respectively.