Novel bioactive bromopyrrole alkaloids from the Mediterranean sponge Axinella verrucosa

Marine pharmacology in 2005-6: Marine compounds with anthelmintic, antibacterial, anticoagulant, antifungal, anti-inflammatory, antimalarial, antiprotozoal, antituberculosis, and antiviral activities; affecting the cardiovascular, immune and nervous systems, and other miscellaneous mechanisms of action

BACKGROUND

The review presents the 2005-2006 peer-reviewed marine pharmacology literature, and follows a similar format to the authors' 1998-2004 reviews. The preclinical pharmacology of chemically characterized marine compounds isolated from marine animals, algae, fungi and bacteria is systematically presented.

RESULTS

Anthelmintic, antibacterial, anticoagulant, antifungal, antimalarial, antiprotozoal, antituberculosis and antiviral activities were reported for 78 marine chemicals. Additionally 47 marine compounds were reported to affect the cardiovascular, immune and nervous system as well as possess anti-inflammatory effects. Finally, 58 marine compounds were shown to bind to a variety of molecular targets, and thus could potentially contribute to several pharmacological classes.

CONCLUSIONS

Marine pharmacology research during 2005-2006 was truly global in nature, involving investigators from 32 countries, and the United States, and contributed 183 marine chemical leads to the research pipeline aimed at the discovery of novel therapeutic agents.

GENERAL SIGNIFICANCE

Continued preclinical and clinical research with marine natural products demonstrating a broad spectrum of pharmacological activity will probably result in novel therapeutic agents for the treatment of multiple disease categories.

Purine alkaloids from the South China Sea gorgonian Subergorgia suberosa

Four new purine alkaloids, namely, 6-(1'-purine-6',8'-dionyl)suberosanone ( 1), 3,9-(2-imino-1-methyl-4-imidazolidinone-5-yl)isopropenylpurine-6,8-dione ( 2), 1-(3'-carbonylbutyl)purine-6,8-dione ( 3), and 9-(3'-carbonylbutyl)purine-6,8-dione ( 4), together with three known compounds, guanosine ( 5), thymidine ( 6), and adenosine ( 7), were isolated from the EtOH/CH 2Cl 2 extracts of the South China Sea gorgonian Subergorgia suberosa. The structures of 1- 4 were determined on the basis of extensive spectroscopic analysis, including 1D and 2D NMR data. Compounds 1- 4 all showed weak cytotoxicity toward human cancer cell lines MDA-MB-231 and A435.

Marine natural products

This review covers the literature published in 2006 for marine natural products, with 758 citations (534 for the period January to December 2006) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, cnidaria, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (779 for 2006), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Syntheses of manzacidins: a stage for the demonstration of synthetic methodologies

Manzacidins, a family of bromopyrrole alkaloids, have attracted much attention from the synthetic community due to their intriguing structures, bearing chiral tertiary and secondary stereocentres in a 1,3-relationship, and biological activities. In this article, we summarise the approaches for the preparation of manzacidins using novel synthetic methodologies. Organocatalysis and Lewis acid catalysis, as well as transition-metal catalysis, offered efficient ways to access these molecules.

Dissecting non-ribosomal and polyketide biosynthetic machineries using electrospray ionization Fourier-Transform mass spectrometry

Many virulence factors and bioactive compounds with antifungal, antimicrobial, and antitumor properties are produced via the non-ribosomal peptide synthetase (NRPS) or polyketide synthase(PKS) paradigm. During the biosynthesis of these natural products, substrates, intermediates and side products are covalently tethered to the NRPS or PKS catalyst, introducing mass changes, making these biosynthetic systems ideal candidates for interrogation by large molecule mass spectrometry. This review serves as an introduction into the application of electrospray ionization Fourier-Transform massspectrometry (ESI-FTMS) to investigate NRPS and PKS systems. ESI-FTMS can be used to understand substrate tolerance, timing of covalent linkages, timing of tailoring reactions and the transfer of substrates and biosynthetic intermediates from domain to domain. Therefore we not only highlight key mechanistic insights for thiotemplate systems as found on the enterobactin,yersiniabactin, epothilone, clorobiocin, coumermycin, pyoluteorin, gramicidin, mycosubtilin, C-1027,6-deoxyerythronolide B and FK520 biosynthetic pathways, but we also explain the approaches taken to identify active sites from complex digests and compare the FTMS based assay to traditional assays and other mass spectrometric techniques. Although mass spectrometry was introduced over two decades ago to investigate NRPS and PKS biosynthetic systems, this is the first review devoted to this methodology.