Bromoallenes from the alga Laurencia microcladia

Kennedy, Derek J.; Selby, I. A.; Cowe, Heather J.; Cox, Philip; Thomson, R. H.

doi:10.1039/c39840000153

Cited by 34 publications

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“…The efficient isomerization of (Z)-enyne systems to (E)-enyne was exemplified by the chemical conversion of laureatin (864) to (E)-isolaureatin (865) [788]. Microcladallenes A (887), B (889), and C (888), initially isolated from L. microcladia collected off the French coast at Cape Ferrat [750], are the only examples of acetogenins incorporating a 4,10:9,13-bisepoxy core in their structures. All three bear a bromoallene moiety as the terminus and a bromine atom at C-12.…”

Section: Acetogenins Containing An Eight-membered Cyclic Ether (Oxocamentioning

confidence: 99%

The Laurencia Paradox: An Endless Source of Chemodiversity

Harizani

Iοannou

Roussis

2016

Progress in the Chemistry of Organic Natural Products

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Nature, the most prolific source of biological and chemical diversity, has provided mankind with treatments for health problems since ancient times and continues to be the most promising reservoir of bioactive chemicals for the development of modern drugs. In addition to the terrestrial organisms that still remain a promising source of new bioactive metabolites, the marine environment, covering approximately 70% of the Earth's surface and containing a largely unexplored biodiversity, offers an enormous resource for the discovery of novel compounds. According to the MarinLit database, more than 27,000 metabolites from marine macro- and microorganisms have been isolated to date providing material and key structures for the development of new products in the pharmaceutical, food, cosmeceutical, chemical, and agrochemical sectors. Algae, which thrive in the euphotic zone, were among the first marine organisms that were investigated as sources of food, nutritional supplements, soil fertilizers, and bioactive metabolites.Red algae of the genus Laurencia are accepted unanimously as one of the richest sources of new secondary metabolites. Their cosmopolitan distribution, along with the chemical variation influenced to a significant degree by environmental and genetic factors, have resulted in an endless parade of metabolites, often featuring multiple halogenation sites.The present contribution, covering the literature until August 2015, offers a comprehensive view of the chemical wealth and the taxonomic problems currently impeding chemical and biological investigations of the genus Laurencia. Since mollusks feeding on Laurencia are, in many cases, bioaccumulating, and utilize algal metabolites as chemical weaponry against natural enemies, metabolites of postulated dietary origin of sea hares that feed on Laurencia species are also included in the present review. Altogether, 1047 secondary metabolites, often featuring new carbocyclic skeletons, have been included.The chapter addresses: (1) the "Laurencia complex", the botanical description and the growth and population dynamics of the genus, as well as its chemical diversity and ecological relations; (2) the secondary metabolites, which are organized according to their chemical structures and are classified into sesquiterpenes, diterpenes, triterpenes, acetogenins, indoles, aromatic compounds, steroids, and miscellaneous compounds, as well as their sources of isolation which are depicted in tabulated form, and (3) the biological activity organized according to the biological target and the ecological functions of Laurencia metabolites.

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Section: Acetogenins Containing An Eight-membered Cyclic Ether (Oxocamentioning

confidence: 99%

The Laurencia Paradox: An Endless Source of Chemodiversity

Harizani

Iοannou

Roussis

2016

Progress in the Chemistry of Organic Natural Products

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“…As for the fourth and fifth subclasses (474−518, Figures 40 and 41), a bromopropyl unit frequently occurs at one terminus, with the other consisting of either a cis-or trans-enyne moiety for the fourth subclass (474− 506, Figure 40) or a bromoallenic or bromopropargylic units for the fifth subclass (510−518, Figure 41). Microcladallenes A−C (519−521, Figure 42) identified from L. microcladia (off the French coast at Cape Ferrat) 329 and marilzabicycloallenes A−D (522−525, Figure 42) isolated from a newly described species L. marilzae (Canary Islands, Spain), 330 are the only representatives of the sixth and seventh subclasses of ACG derivatives to be reported so far. Each of these compounds contains a bromoallenic unit at one terminus and an ethyl-(519 and 521), or olefinic (520) Figure 43 and Supporting Information Table S13), was isolated independently by two research groups from L. obtusa with samples collected from Positano, Italy 299 and from Gokceada in the Aegean Sea.…”

Section: Halogenated Nonterpenoid C 15 -Acetogenins (Acgs)mentioning

confidence: 99%

“…In addition to the halogenated diterpenes discussed above, 28 diterpenes (319−346, Figures 26 and 27 and Supporting Information Table S11) with 14 new or rarely reported carbon skeletons were also discovered from species of the family Rhodomelaceae. 67,145,149,192,193,214−229 These diterpenes, as summarized in Supporting Information Table S11, possess a diverse array of ring systems including mono-(319−324), bis-(325−334), and tricarbocyclic systems (335−346), with some of them containing spiro-(339−341) or cyclic ether/epoxide (320,323,324,329,338, and 339) systems. All of these diterpenes are brominated, with two of them, dactylomelol (320) 215 and laurencianol (324), 217 also containing a chlorine atom.…”

Section: Halogenated Diterpenesmentioning

confidence: 99%

Halogenated Organic Molecules of Rhodomelaceae Origin: Chemistry and Biology

et al. 2013

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“…mon type, oxocanes, albeit new like microcladallene A [1]. No other metabolites have been described for this alga.…”

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confidence: 96%

“…From these families of metabolites of vastly different biogenesis it is apparent that the secondary enzyme systems of these three samples of seaweed, determined microscopically by expert taxonomists to be L. microcladia Kützing, 1865 [1,3,4], are largely unrelated to each other. The differences should be traced back to the coding genes.…”

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confidence: 98%

Evolution of the secondary metabolite versus evolution of the species

Pietra¹

2002

Pure and Applied Chemistry

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Four stereochemical series of diastereomeric polyhalogenated chamigrane sesquiterpenes-headed by obtusol, isoobtusol, rogiolol, and cartilagineol-suggest the existence of four lineages of red seaweeds in the genus Laurencia. On another front, concerning marine ciliates, euplotane sesquiterpenes characterize worldwide the morphospecies Euplotes crassus, well differentiated from Euplotes raikovi, Euplotes rariseta, and Euplotes vannus, which furnish different-skeleton sesquiterpenoids, and the latter also C 30 -backbone isoprenoids. The latter three morphospecies, however, show polymorphism in the variability of their isoprenoids.Unarguably, the modern construction of phylogenetic trees and evolutionary events concerning species is based on molecules that are found in all organisms, such as rRNA coding fractions and highly conserved proteins for long distances, or polymorphic enzymes for population structure and dynamics. However, the correlation between gene and protein expression is low, and that between proteins and secondary metabolites is even lower, which throws much shadow on "lower" species that compete for space and resources, or defend themselves from predators, largely thanks to secondary metabolites. These often constitute their best taxonomic and phylogenetic markers. In this regard, biologists and natural products chemists live largely in separate, artificial worlds-the evolutionary biologist snubbing the secondary metabolite, and the chemotaxonomy of the natural products chemist providing little trait d'union, as it is typically concerned with gross comparisons of identities or similarities in molecular structures that ignore deep-seated chemical features.An example of gross structural comparison concerns a nominal species of red seaweed, Laurencia microcladia Kützing, 1865, of Atlantic origin although rather common in infralittoral areas of the Mediterranean (Fig. 1). The story begins with a sample of this seaweed from Cap Ferrat, along the Côte d'Azur, giving new polyhalogenated C 15 acetogenins, a class of compounds unique to seaweeds in the genus Laurencia and opisthobranch mollusks that feed on them. In this case, these are of the most com-*Lecture presented at

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Bromoallenes from the alga Laurencia microcladia

Abstract: The structures of the microcladallenes A, B, and C have been established from spectroscopic data and X-ray crysta I I og ra p h ic an a I ysis of m icrocl a d a I I e n e B.

Cited by 34 publications

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The Laurencia Paradox: An Endless Source of Chemodiversity

The Laurencia Paradox: An Endless Source of Chemodiversity

Halogenated Organic Molecules of Rhodomelaceae Origin: Chemistry and Biology

Evolution of the secondary metabolite versus evolution of the species

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