Spheciosterol Sulfates, PKCζ Inhibitors from a Philippine Sponge Spheciospongia sp.

Three new sterol sulfates, spheciosterol sulfates A−C ( 1 − 3 ), and the known sterol sulfate topsentiasterol sulfate E ( 4 ) have been isolated from the sponge Spheciospongia sp., collected in the Philippines. Structures were assigned on the basis of extensive 1D and 2D NMR studies as well as analysis by HRESIMS. Compounds 1 − 4 inhibited PKCζ with IC50 values of 1.59, 0.53, 0.11, and 1.21 μM, respectively. In a cell-based assay, 1 − 4 also inhibited NF-κB activation with EC50 values of 12−64 μM.