Xestosaprols from the Indonesian marine sponge Xestospongia sp

Eight pentacyclic compounds, xestosaprols F-M (1-8), were isolated from a marine sponge belonging to the genus Xestospongia. The structures of these new compounds were determined on the basis of extensive analyses of NMR experiments and mass spectrometric measurements. These compounds inhibited the aspartic protease BACE1 at moderate levels in a dose-dependent manner.