2,632,099 research outputs found

    Review: Marine natural products

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    This review covers the literature published in 2003 for marine natural products, with 619 citations (413 for the period January to December 2003) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (656 for 2003), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies or syntheses that lead to the revision of structures or stereochemistries have been included (78), including any first total syntheses of a marine natural product

    Biosynthesis of thiocarboxylic acid-containing natural products.

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    Thiocarboxylic acid-containing natural products are rare and their biosynthesis and biological significance remain unknown. Thioplatensimycin (thioPTM) and thioplatencin (thioPTN), thiocarboxylic acid congeners of the antibacterial natural products platensimycin (PTM) and platencin (PTN), were recently discovered. Here we report the biosynthetic origin of the thiocarboxylic acid moiety in thioPTM and thioPTN. We identify a thioacid cassette encoding two proteins, PtmA3 and PtmU4, responsible for carboxylate activation by coenzyme A and sulfur transfer, respectively. ThioPTM and thioPTN bind tightly to β-ketoacyl-ACP synthase II (FabF) and retain strong antibacterial activities. Density functional theory calculations of binding and solvation free energies suggest thioPTM and thioPTN bind to FabF more favorably than PTM and PTN. Additionally, thioacid cassettes are prevalent in the genomes of bacteria, implicating that thiocarboxylic acid-containing natural products are underappreciated. These results suggest that thiocarboxylic acid, as an alternative pharmacophore, and thiocarboxylic acid-containing natural products may be considered for future drug discovery

    Studies on Natural Products of Albizia SP.

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    The bark of Albizia lebeckioides and Albizia falcataria have been examined for their chemical constituents. A. lebeckioides has yielded the steroidal ketone, stigmasta-4,22-dien-3-one, and a triterpene alcohol as the major neutral components. A. falcataria has yielded a similar triterpene and fatty ester as its major constituents. The toxicity of the compounds was evaluated in bioassay against termites. The results showed that lupenone and stigmastadienone were toxic ioNeotermes dalbergiae species. In contrast these compounds were less toxic to Cryptotermes cynocephalus species

    Multi-Omic Profiling of Melophlus Sponges Reveals Diverse Metabolomic and Microbiome Architectures that Are Non-overlapping with Ecological Neighbors.

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    Marine sponge holobionts, defined as filter-feeding sponge hosts together with their associated microbiomes, are prolific sources of natural products. The inventory of natural products that have been isolated from marine sponges is extensive. Here, using untargeted mass spectrometry, we demonstrate that sponges harbor a far greater diversity of low-abundance natural products that have evaded discovery. While these low-abundance natural products may not be feasible to isolate, insights into their chemical structures can be gleaned by careful curation of mass fragmentation spectra. Sponges are also some of the most complex, multi-organismal holobiont communities in the oceans. We overlay sponge metabolomes with their microbiome structures and detailed metagenomic characterization to discover candidate gene clusters that encode production of sponge-derived natural products. The multi-omic profiling strategy for sponges that we describe here enables quantitative comparison of sponge metabolomes and microbiomes to address, among other questions, the ecological relevance of sponge natural products and for the phylochemical assignment of previously undescribed sponge identities

    Aryne Acyl-Alkylation in the General and Convergent Synthesis of Benzannulated Macrolactone Natural Products: An Enantioselective Synthesis of (−)-Curvularin

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    A general approach for the synthesis of benzannulated macrolactone natural products utilizing an aryne acyl-alkylation reaction is described. Toward this end, the total syntheses of the natural products (−)-curvularin, curvulin, and (−)-diplodialide C are reported. Furthermore, the aryne insertion technology has enabled the rapid conversion of simple diplodialide natural products to curvularin, thereby connecting these two biosynthetically distinct classes of compounds via synthetic methods

    Slim and scum: Natural products from land and sea

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    To a natural-products chemist, the term "natural products" does not refer to all compounds from natural sources, as the name might imply. It is specifically used to refer to compounds known as secondary metabolites, structurally complex molecules, often of unknown function, with very limited biological distribution

    A Comparison of Wholesaler/Retailer Business Characteristics of Natural Products between Ghana and Rwanda

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    The usage of natural products is becoming an increasingly common consumer phenomenon due to increasing health consciousness, and because of their naturalness, and medicinal qualities of the products. African countries are very rich with natural products resources and supplies. The continent’s rich botanical heritage offers an excellent opportunity to diversify away from other traditional exports. Europe and the USA are particularly promising markets for natural products. Thus, it is advantageous to examine development of natural products exporting as alternative or complimentary economic opportunities for many African people, especially those in the rural areas. This paper has explores both factors which promote and which act as obstacles to the natural products market, specifically in the retail and wholesale portions of the value chain in Ghana and Rwanda.Agribusiness,
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