Bioactive metabolites from marine organisms.

The marine molluscs Siphonaria pectinata, S. normalis, Onchidium verruculatum and Peronia peronii were investigated because they are trail following species, that are known to possess repugnatorial skin glands. Extraction of the skin glands of these organisms led to the isolation of the compounds, pectinatone, dihydrosiphonarins A and B, ilikonapyrone and peroniatriols I and II, respectively. The marine tunicate, Lissoclinum patella was also studied because the original methanol extract of the tunicate exhibited a variety of biological activities. A series of eight cytotoxic cyclic peptides have been isolated from this tunicate, all of which contain thiazole and oxazoline amino acids as a common structural feature.