Siphonodictidine, a Metabolite of the Burrowing Sponge Siphonodictyon sp. that Inhibits Coral Growth

Siphonodictidine is the major secondary metabolite of an undescribed Indo-Pacific sponge Siphonodictyon sp. that burrows into living coral heads. The structure of siphonodictidine was determined from spectral data. Laboratory bioassays suggest that siphonodictidine and, by analogy, the siphonodictyals from S. coralliphagum are responsible for maintaining zones of dead coral polyps around the oscular chimneys of these sponges.