Marine secondary metabolite

Several reviews on marine chemical ecology and marine secondary metabolites cover aspects of the plankton and only a selection of recent contributions are cited here (Paul and Puglisi 2004 Ianora et al. 2006 Paul et al. 2006). 

In the search for bioactive marine secondary metabolites, drugs or drug leads with new modes of action, many invertebrates with new modes of action have been explored and tested in a variety of assays. Many marine natural products were found to be cytotoxic to an assortment of tumor cells, Some parts of the marine natural products were also found to be ichthyotoxic so as to defend themselves. Two examples, out of many, are the latrunculins and sarcophine. ... 

The reader is referred to articles by Barrow,12 Garson,1314 and Moore15 for background information on the field of marine secondary metabolite biosynthesis. Early work in this field used radiochemical tracers such as 14C or 3H recently, studies with 13C have proved popular because of the ease of detection of this stable isotope by nuclear magnetic resonance (NMR). In particular, our understanding of marine microbial biosynthesis and of de novo biosynthesis in marine molluscs has progressed significantly as a consequence of the use of 13C-labeled precursors. 

Given the number and diversity of secondary metabolites and their broad range of pre-ingestive bioactivities, it is of interest to speculate on the effect of these compounds (which can be present in plants and prey at concentrations that constitute approximately 20% of the dry tissue mass) once they are consumed. This chapter reviews what is known about the consumers post-ingestive response to marine secondary metabolites, focusing on marine herbivores, since... 

T. Luke Simmons obtained his Ph.D. from the University of California, San Diego where he studied the bioorganic chemistry and structure elucidation of marine secondary metabolites under Professor William H. Gerwick. Luke s research interests focus on harnessing the molecular mechanisms of natural product biosynthesis for the investigation and discovery of therapeutically relevant small molecules. He is currently a postdoctoral associate in the laboratory of Sean F. Brady at The Rockefeller University. 

The widespread nature of secondary metabolite production and the preservation of their multigenic biosynthetic pathways in nature indicate that secondary metabolites serve survival functions in organisms that produce them. There are a multiplicity of such functions, some dependent on antibiotic activity and others independent of such activity. Indeed in the latter case, the molecule may possess antibiotic activity but may be employed by a producing microorganism for an entirely different purpose. Some useful reviews on secondary metabolism have appeared in recent years [23,47 -49]. Examples of marine secondary metabolites playing a role in marine ecology have been given by Jensen and Fenical [50]. 

Most often chiral metabolites are characterized by optical activity because of their origin in enzyme mediated reaction sequences. In fact, this rule is of such generality that the first example of a marine secondary metabolite of low enantiomeric purity (8-9) appeared as recently as in 1984. 

Although the marine environment is a plentiful source of interesting new products with pharmaceutical potential, only a few of these marine natural products have reached the stage of commercial production. Arabinofuranosyladenine (ara-A, isolated from the Gorgonian Eunicella cavolini) [210] is the unique marine secondary metabolite currently in clinical use and is one of most potent antiviral drugs [211]. The second one is avarol, a sesquiterpene hydroquinone isolated from the sponge... 

Table 12 illustrates the reported antiviral activities of the common marine secondary metabolites polyacetylenes, quinones/pyrones, macrolides and prostaglandins. 

Diazonamide A (136), a marine secondary metabolite from a colonial ascidian Diazona chinensis, has been synthesized more than once (2008NPR227) Indeed, the original and incorrect structure was also synthesized. Schemes 20 and 21 give some of Nicolaou s incredible route that led to the correct structure, thus securing it—it starts simply from a 7-bromoi-satin (128) (2004JA12888) It is ironic that with all the powerful physical... 

Hay, M.E. 1992. Seaweed chemical defenses their role in the evolution of feeding specialization and in mediating complex interactions. In Ecological Roles for Marine Secondary Metabolites Explorations in Chemical Ecology Series, ed. V.J. Paul, pp. 93-118, Comstock, Ithaca. 

The enzyme topoisomerase II has been shown to be a useful indicator for predicting activity against certain lung cancers. Among marine secondary metabolites which have been isolated in my laboratory are two stmcturally diverse compounds which possess that activity. 

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