In order to check the structure-activity relationship and find more potent derivatives of the natural products 1 and 2 obtained from sponge Ircinia spinosula, a series of oxidation, hydrogenation, acetylation and methylation derivatives was prepared. All compounds (natural and synthetic ones) were screened for their cytotoxic and antibacterial activities. The biological studies showed a wide range of antibacterial activity even though only 2 and 2d showed a moderate cytotoxicity against the clone C98. The oxidation of the hydroquinone to quinone and the hydrogenation of the side-chain increased the antibacterial effect of the molecules
