Dear Colleagues,

The recent introduction to the clinic of trabectedin (Et-743) as a treatment for soft tissue sarcoma highlights the potential of marine drugs as novel antitumour agents. There is a huge and largely untapped array of small molecules in the depths of the ocean, produced by novel organisms that are only now being discovered. Other compounds that have captured the imagination include the dolastatins, bryostatins, kahalalides, didemnins, halchondrins, lamellarins and thiocaroline. The structurally diversity among this compounds is immense, from cyclic and linear peptides to products of the polyketide and alkaloid biosyntehsis pathways. There are diterpenes, pyrrole alkaloids, depsipeptides, macrolides and steroids. The targets for these natural products show a similar array of diversity, from tubulin inhibitors to other protein targets such as caspases and cyclin dependent kinases. The isolation and identification of new marine natural products with antitumour activity with be a key feature of this special issue of Marine Drugs. However, as with all natural products, these compounds were not produced in nature to act as antitumour agents, and while it may seem arrogant to suggest that we can improve on nature, this is where total synthesis and studies of structure activity relationships come into their own. The total synthesis of new natural products is clearly still of great important in the elucidation and confirmation of structure and absolute stereochemistry. But it also can contribute to our understanding of the mechanism of action of the natural product as an antitumour agent and can contribute to the design of analogues with enhanced activity. The second focus of this special issue of Marine Drugs will be on the synthesis and study of the mode of action of antitumour agents derived from the Sea.

Dr. Mark Searcey
Guest Editor

• antitumour agents
• marine compounds
• total synthesis
• structure-activity relationships
• medicinal chemistry
• biological activity