Isolating bioactive compounds from marine organisms

The strategies used for isolation and structural elucidation of pharmacologically active metabolites from marine organisms are discussed, with examples of cytotoxic and antihistaminic compounds from marine equinoderms, sponges, gorgonians, ascidians, and tunicates from the author's laboratory. Special attention will be paid to isolation procedures adapted to the physical and chemical characteristics of the compounds isolated, particularly to their polarity and lipo-or hydrophilic character. Examples of isolation from water-soluble material of highly polar metabolites such as saponins, polyhydroxysteroids, alkaloids, and amino acids will be presented. Sesquiterpene quinones, polypropionates, peptides, and depsipeptides from the extracts of medium or low polarity are also described. The relevance of recent spectroscopic techniques-especially exhaustive 2D NMR and MS analysis-in the structural elucidation of complex structures and the usefulness of new reagents for the assignment of absolute configuration by H-1 NMR are presented.