Marine natural products research

The majority of promising drug candidates emerging from marine natural products research to date are potential cancer treatments. Six anti-cancer compounds that are either marine natural products or synthetic analogs of marine natural products have made it to clinical trials. The first of these compounds to enter clinical trials was didemnin B (43), one of a family of cyclic depsipetides isolated from the Caribbean tunicate Trididemnum solidum Didemnin B was advanced to Phase II clinical trials for treatment of small cell lung cancer, myeloma, prostate cancer, and melanoma. Unfortunately, no favorable responses were found so the compound has been withdrawn. Crude extracts of another Caribbean tunicate, Ecteinascidia turbinata, showed extremely... 

A continuous series of very excellent reviews on marine natural products by D. J. Faulkner has appeared in Natural Products Reports (2-6), covering all aspects of the literature on marine natural products, organized phylogenetically. Excellent reviews on Marine Alkaloids and Related Compounds (7) and Recent Developments in the Field of Marine Natural Products with Emphasis on Biologically Active Compounds (5) were written by W. Fenical and H. C. Krebs, respectively. Besides these reviews, numerous books dealing with general or specialized topics in marine natural products research have appeared in recent years (9-13). Biosynthetic studies on marine natural products were recently reviewed by M. J. Garson (14). 

Konig, G. M. and Wright, A. D., Marine natural products research. Current directions and future potential, Planta Med., 62, 193, 1996. 

Konig, G. Wright, A. "Marine Natural Products Research Current Directions and Future Potential", Planta Med., 1996, 62, 193-211. 

Marine Natural Products Research in Southern Africa - A Brief Historical Perspective... 

Marine fatty acids continue to occupy a central role in modem marine natural products research because of the unusual array of structural motifs constantly being discovered. Most novel fatty acids were identified in marine invertebrates or marine microorganisms. Although excellent reviews of the syntheses of terrestrial fatty acids are published frequently and several outstanding reviews about the chemistry of fatty acids have appeared recently [1], there has been no review of the synthetic methodology used in the preparation of marine fatty acids. Therefore, this review presents a compilation of what has been published recently regarding the synthesis of unusual marine fatty acids, some of... 

The underlying assumption driving marine natural products chemistry research is that secondary metabolites produced by marine plants, animals, and microorganisms will be substantially different from those found in traditional terrestrial sources simply because marine life forms are very different from terrestrial life forms and the habitats which they occupy present very different physiological and ecological challenges. The expectation is that marine organisms will utilize completely unique biosynthetic pathways or exploit unique variations on well established pathways. The marine natural products chemistry research conducted to date has provided many examples that support these expectations. 

Figure 3.3. Bryostatin 2. Bryostatin 2 (C HggOjg) is a biologically active marine natural product which may have useful anti-cancer properties. It was recently synthesised at Harvard by Professor David Evans and his research group. In this illustration, all of the hydrogen atoms are omitted in order to simplify the structure. The lower diagram shows a low energy conformation of bryostatin 2, but it may only be a local minimum and not a global minimum. Many other conformations are accessible at room temperature.

Mickel, S.J., Sedelmeier, G.H., Niederer, D. etal. (2004) Large-Scale Synthesis of the Anti-Cancer Marine Natural Product (-P)-Disco derm olide. Part 1 Synthetic Strategy and Preparation of a Common Precursor. Organic Process Research Development, 8, 92-100. 

The ocean is a rich source of natural products, and their structural variety has inspired numerous chemists and chemical ecologists. Comprehensive reviews exist on the structure and occurrence, biosynthesis, and biological activity of marine natural products (see, e.g., [ 1-5]). An excellent book published in 2001 that deals exclusively with marine chemical ecology highlights different aspects of chemical communication and chemical defense [6]. It would be impossible to cover all aspects of chemical defense in this environment, and thus this contribution will focus on a few selected aspects that have been under intense research and discussion in recent years. 

Marine Natural Products - Diversity and Biosynthesis contains four chapters, which review some of the most lively research topics in the field, all written by active contributors. 

Steroid chemistry, the glamor area of natural product research in the years following World War II, was replaced by macrolides, alkaloids, and prostanoids. Sterol chemistry again became exciting when an unanticipated rich diversity of marine invertebrate sterols were isolated, notably from sponges. After pioneering research in Italy, the field was reborn in Carl Djerassi s laboratory at Stanford. As a result, we now have a better and more detailed knowledge of sterol biosynthesis than of any other class of marine natural products. The authors of Chapter 1 are Stanford alumni. 

Early natural product research with marine mollusks supported a conclusion that all secondary metabolites of mollusks are diet-derived, which proved to be premature. In fact, the biosynthetic capability of some marine mollusks covers a wide spectrum of chemical classes and substances. Much of this recent insight has resulted from work in the laboratories of the authors of Chapter 3. 

The study of marine natural products has great possibilities for new products. Thus, Paul Scheuer from Hawaii studied bioactive compounds from mollusks and other marine sources. Luigi Minale, Raffaele Riccio and Maria lorizzi from Italy, conducted a comprehensive research on marine steroidal glycosides. Joel Kashman from Tel-Aviv University investigated on the biologically active natural products from marine organisms. 

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