Natural products from marine invertebrates

SULFUR-CONTAINING NATURAL PRODUCTS FROM MARINE INVERTEBRATES... 

Newman DJ, Cragg GM. Natural products from marine invertebrates and microbes as modulators of antitumor targets. Curr. Drug Target. 2006 7 279-304. 

PROKSCH p, EBEL R, EDRADA R A, WRAY V and STEUBE K (2003), Bioactivc natural products from marine invertebrates and associated fungi. In W. E. G. Miiller (ed.), Progress in Molecular and SubceUular Biology, Sponges, Springer-Verlag, BerUn, 117-142. 

When larvae fail to settle in a particular test situation, is it due to the absence of positive cues, or are there other factors that prohibit settlement, even when positive cues may be present This is a difficult question to answer because of the possibility that a negative cue may, in fact, be a neutral substance that simply makes the positive cue undetectable by a larva, rather than a substance that causes a larva to reject a potential settlement site. Much effort to demonstrate negative cues to settlement has come from the search for antifouling natural products from marine organisms (reviewed by Pawlik 3 see also Chapters 10 and 17 in this volume). However, there is little reason to believe that extracted compounds which are toxic or aversive to invertebrate larvae have any such function in nature. The best evidence to date for chemical deterrence of larval settlement comes from the work of Woodin and co-workers.212 214 Focusing on halogenated compounds released by many marine polychaete and enteropneust worms,212 they have shown inhibition of settlement of larvae of other species in the presence of the compounds.213 214... 

Pomponi, S. A., Willoughby, R., Kaighn, M. E., and Wright, A. E., Development of techniques for in vitro production of bioactive natural products from marine sponges, in Invertebrate Cell Culture Novel Directions and Biotechnology Applications, Maramorosch, K. and Mitsuhashi, J., Eds., Academic Press, New York, 1997. 

Preservation of natural products from the animals is more difficult. Zoos remain living stores of animals that, like the civet cat and the amphibians, give unusual metabolites. Aquaria might serve the same scope for marine invertebrates. However, many productive species, such as the sponges and the anthozoans, do not survive long in aquaria. 

Metabolites of the phylum Porifera account for almost 50% of the natural products reported from marine invertebrates. Of the 2609 poriferan metabolites, 98% are derived from amino acid, acetogenin, or isoprenoid pathways. Isoprenoids account for 50% of all sponge metabolites, while amino acid and polyketide pathways account for 26% and 22%, respectively. A significant number of sponge metabolites appear to be derived from mixed biosynthetic pathways. Most structures reported containing carbohydrate moieties were glycosides. 

Ireland, C. M., Molinski, T. F., Roll, D. M., Zabriskie, T. M., McKee, T. C., Swersey, J. F., and Foster, M. P., Uniqueness of the marine chemical environment categories of marine natural products from invertebrates, in Biomedical Roles of Marine Natural Products, Fautin, D. G., Ed., California Academy of Sciences, San Francisco, 1988, 41. 

The lamellarins constitute an important group of natural products isolated from marine invertebrates such as sponges, molluscs and tunicates with structures without precedents in natural or synthetic compounds. They are characterized for possessing important biological activities. The aim of this review is to provide an overview of the work published since the isolation of the first group of lamellarins <85JA5492> from the marine prosobranch mollusc Lamellaria sp, imtil the beginning of 2004. 

Oceans provide enormous and diverse habitats for marine life. The distinct feature of marine life is the domination of invertebrates, which account for more than 95% of marine animals. Most marine invertebrates are sessile and soft-bodied and lack obvious physical defenses. Instead, they have evolved to defend by chemical means against predation and overgrowth by other fouling organisms. In fact, their secondary metabolites have unusual structural features and potent biologic activities, many of which are not found in terrestrial natural products. This review focuses on bioactive metabolites isolated mainly from marine invertebrates with a special emphasis on the uniqueness of marine natural products. 

ABSTRACT Marine invertebrates such as ascidians, sponges and others are a prolific source of bioactive secondary metabolites. We have isolated a variety of marine natural products from the Okinawan marine invertebrates by using the sea urchin egg assay. Our recent work, the isolation, structure determination and activities of chlorinated macrolides, sesterterpenic acids, a bromotyrosine derivative, acetogenin derived endoperoxides, diterpene alkaloids, sesquiterpene quinones and spiro-sesquiterpenes, is presented in this article. The syntheses of these metabolites are also described. 

As part of their ongoing investigation of bioactive natural products from tropical marine invertebrates collected in Sodwana Bay (situated in northern Kwazulu-Natal, South Africa), Kashman and co-workers isolated three novel alkaloids, polycitone A (89) and polycitrins A and B (90 and 91) from an ascidian Polycitor sp. [86]. The structure of 89 was established from X-ray data while the structures of 90 and its mono-O-methyl ether analogue, 91, followed from analysis of the NMR data of these two compounds. Two possible biosynthetic precursors of 89-91,... 

The marine environment has become an important source of new structures and new activities, and this is reflected in the next three chapters, which review bioactive natural products from South African marine invertebrates, bioactive marine sesterterpenoids, and antimalarial leads from marine organisms. 

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