Brominated cyclodipeptides from the marine sponge Geodia barretti as selective 5-HT ligands

Abstract

The production of bioactive compounds by plants, animals and microorganisms has long been exploited in the search for drug candidates to serve as leads in drug development. Traditionally, such bioprospecting for drug candidates has focused on terrestrial microorganisms and plants; the equivalent research in marine systems is in its infancy, but the much larger diversity of major lineages in the sea promises a wealth of new molecular structures with as yet unknown functions. In the ocean, sessile sponges have proved a rich source of bioactive compounds many of which are believed to constitute a chemical defense against predators or foulers aimed at protecting the body surface. We have previously reported on the production of the brominated cyclodipeptides barettin (cyclo[(6-bromo-8-entryptophan)arginine]) and 8,9-dihydrobarettin (cyclo[(6-bromotryptophan)arginine in the marine sponge Geodia barretti Bowerbank and their ability to inhibit settlement of barnacle larvae in a dose-dependent manner [1].