HYRTIOSAL, A NEW SESTERTERPENOID WITH A NOVEL CARBON SKELETON FROM THE OKINAWAN MARINE SPONGE HYRTIOS-ERECTUS

Hyrtiosal, a new sesterterpenoid possessing a novel rearranged tricarbocyclic skeleton, was isolated from the Okinawan marine sponge, Hyrtios erectus (Keller, 1891). This compound was shown to inhibit the proliferation of KB cells in vitro, and its structure was determined by chemical and spectral methods including two-dimensional C-13-H-1 long-range correlations. The relative stereochemistry was determined based on two-dimensional NOE correlations. A possible biosynthesis of hyrtiosal is briefly discussed.