Isolation of Xestosterol Esters of Brominated Acetylenic Fatty Acids from the Marine Sponge Xestospongia testudinaria

The CH<INF>2</INF>Cl<INF>2</INF> extract of the marine sponge Xestospongia testudinaria inhibited [³H]DPCPX binding to rat-brain adenosine A<INF>1</INF> receptors. Bioassay-guided fractionation led to the isolation of a known brominated acetylenic fatty acid <BO>1</BO> as the active component. Also isolated were two novel sterol esters <BO>2</BO> and <BO>3</BO>. All structures were determined on the basis of their spectroscopic data.