Evidence for de novo biosynthesis of the polyketide fragment of diaulusterol A by the northeastern pacific dorid nudibranch diaulula sandiegensis

Stable isotope incorporation experiments using sodium [1, 2-13C2]acetate have demonstrated that the 3-hydroxybutyrate substituent of diaulusterol A (1) is biosynthesized de novo by the dorid nudibranch Diaulula sandiegensis. There was no evidence for acetate incorporation into the steroid portion of 1, nor were radiolabeled mevalonate or cholesterol incorporated.

A beta-carboline alkaloid from the soft coral lignopsis spongiosum

From an EtOH extract of Lignopsis spongiosum, a new beta-carboline alkaloid, 2-methyl-9H-pyrido[3,4b]indole-3-carboxylic acid (1), was isolated and characterized by spectral methods.

New Bis(Indole) alkaloids of the topsentin class from the sponge spongosorites genitrix

Four bis(indole) alkaloids of the topsentin class, including two new brominated compounds (1 and 2), have been isolated from the sponge Spongosorites genitrix collected from Jaeju Island, Korea. The structures of the novel compounds were determined by spectroscopic methods. These compounds exhibited moderate cytotoxicity against a human leukemia cell-line (K-562).

Cytotoxic polyacetylenes from the marine sponge Petrosia sp

Three C46 (1-3) and three C30 (4-6) polyacetylenic alcohols with cytotoxic activity against a small panel of human solid-tumor cell lines have been isolated from the marine sponge Petrosia sp. Although compound 1 was identified as the stereoisomer of petrocortyne A, the structures of compounds 2-5 have not been previously reported and were established by spectral methods. Compound 6 was identified as the known compound petrosiacetylene D. The stereochemistry of compounds 1-5 was determined by the modified Mosher's method.

Euplexides A-E: Novel Farnesylhydroquinone Glycosides from the Gorgonian Euplexaura anastomosans

Euplexides A-E (1-5), novel farnesylhydroquinone glycosides of the moritoside class, have been isolated from the gorgonian Euplexaura anastomosans. The structures of these compounds have been elucidated by combined chemical and spectral methods. The absolute stereochemistry has been determined by the modified Mosher's method and an acidic hydrolysis followed by GC analysis. These compounds exhibited moderate cytotoxicity and antioxidizing activity as well as inhibitory activity against PLA(2).

A cyclized didemnimide alkaloid from the caribbean ascidian didemnumconchyliatum

A novel, cyclized alkaloid of the didemnimide class, 5, has been isolated from extracts of the Caribbean ascidian Didemnum conchyliatum. The structure of 5 was assigned using combined spectral methods that emphasized one- and two-dimensional NMR methods. The new alkaloid is the cyclization product of didemnimide A (1) formed via a C-2 indole condensation with the imidazole nitrogen.

New acetylenic enol ethers of glycerol from the sponge Petrosia sp

Ten acetylenic enol ethers of glycerols, including six new compounds (1-6) and a linear acetylenic alcohol (7), have been isolated from a sponge of the genus Petrosia. The structures of the novel compounds were elucidated by spectroscopic methods. The absolute stereochemistry of 1-7 was determined by chemical transformations and the Mosher method. Some of these compounds exhibited weak cytotoxicity against a human leukemia cell-line (K-562).

Tetrahydropyran monoterpenes from plocamium cartilagineum and pantoneura plocamioides

Four new marine monoterpenes have been isolated from two species of marine red algae, Plocamium cartilagineum and Pantoneura plocamioides. The structures and relative stereochemistry of these compounds were determined on the basis of spectroscopic evidence and suggest a relationship between P. cartilagineum and P. plocamioides.

New xenia diterpenes isolated from the soft coral, xenia florida

Seven new xenia diterpenes have been isolated from the soft coral, Xenia florida. Four of them possess a bicyclic [4.3.1] ring system. The three others, which contained a cyclononane skeleton with an epoxide, seem to be precursors for diterpenes with a bicyclic [4.3. 1] ring system.

Peroxypolasol and mugipolasol: two novel diterpenes from the marine sponge epipolasis sp

Two novel diterpenes, peroxypolasol (1) and mugipolasol (2), have been isolated from the Japanese marine sponge Epipolasis sp. The structures of 1 and 2 were determined on the basis of spectroscopic data. Compound 1 is a diterpene with a peroxide ring in the side chain, and 2 is an unusual six/five-membered ring diterpene with an ethyl unit at C-2.

Chemistry of sponges. 18.1 12-desacetylfuroscalar-16-one, a new sesterterpene from a cacospongia sp

A new sesterterpene 12-O-desacetylfuroscalar-16-one (1) has been isolated from the sponge Cacospongia sp., and its structure was determined by spectroscopic examination.

New cyclic polyketide peroxides from okinawan marine sponge plakortis sp

Three new cyclic peroxides (2-4) have been isolated from the Okinawan marine sponge Plakortis sp., and the structures were elucidated by extensive spectroscopic analyses. The absolute stereochemistries of 2 and 3 were determined by chemical conversion, whereas that of the dioxane ring of 4 was assigned by the modified Mosher's method.

Unusual Terpenes with Novel Carbon Skeletons from the West Indian Sea Whip Pseudopterogorgia elisabethae (Octocorallia)(1)

From the hexane solubles of the West Indian gorgonian Pseudopterogorgia elisabethae collected near San Andrés Island, Colombia, were isolated a marine diterpenoid, two nor-diterpenoids, and a bisnor-diterpenoid, all of which possess most unusual carbocyclic skeletons. The structures and relative configurations of novel metabolites elisabethins A-C (1-3) and elisabanolide (4) were elucidated by interpretation of overall spectral data, which included 2D NMR correlation methods; IR, UV, and accurate mass measurements (HREIMS); chemical reactions; and X-ray diffraction analyses. One of these, elisabethin B (2), showed significant differential antitumor activity, and compounds 3 and 4 have weak in vitro antituberculosis activity.

New diketopiperazines from the sponge Dysidea chlorea

Twelve new polychlorinated diketopiperazines (7-18), along with six known ones (1-6) and a known sterol (19), were isolated from the sponge Dysidea chlorea, collected from Yap, Federated States of Micronesia. The structures of dysamides I-T (7-18) were elucidated by spectroscopic methods, and one (8) was confirmed by chemical conversion. The stereochemistry of the dysamides is discussed.

New alkaloids from the papua new guinean sponge agelas nakamurai

Two new bromopyrroles and a new diterpene possessing a 9-methyladenium moiety have been isolated from the Papua New Guinean sponge Agelas nakamurai Hoshino.

Five new polyacetylenes from a sponge of the genus petrosia

Petrocortynes D-H, novel C46 polyacetylenes, were isolated from a sponge of the genus Petrosia collected from Keomun Island, Korea. Petrocortyne D (2) is a 4,5-dihydro derivative of a diastereomer of petrocortyne A (1), and petrocortynes E-H (3-6) possess an additional allylic-hydroxyl group. The structures of these compounds were determined by combined chemical and spectral methods, and absolute configurations of most of the asymmetric carbon centers were determined by the modified Mosher's method. Limitations on the application of Mosher's method to allylic alcohols is discussed. Petrocortynes D-H exhibited moderate cytotoxicity and inhibitory activity against PLA2.

Several new isoprenoids from the soft coral sinularia erecta

Eight compounds were isolated from the Indo-Pacific soft coral Sinularia erecta (Tixier-Durivault, 1945) collected from the lagoon of Mayotte, Comoros Islands, northwest of Madagascar. Four of the compounds, namely the sesquiterpene germacrene D, the diterpenoids nephthenol and decaryiol, and norcembrene, are known. The other four are the new secondary metabolites germacrene E (1), epi-norcembrene (3), and two bis-pukalide diterpenes, mayotolides A and B (4 and 5). The structure of each of the compounds was determined by means of 1D and 2D NMR and MS spectroscopy in addition to some chemical transformations.

Polasols A-C, three new diterpenes from the marine sponge Epipolasis sp

Three new diterpenes, polasols A-C (1-3), have been isolated from the Japanese marine sponge Epipolasis sp. The structures of 1-3 were assigned primarily by 2D NMR methods.

A new cacospongionolide inhibitor of human secretory phospholipase A2 from the Tyrrhenian sponge Fasciospongia cavernosa and absolute configuration of cacospongionolides

A new inhibitor of human secretory phospholipase A2 (PLA2), cacospongionolide E (4a), has been isolated from the Tyrrhenian sponge Fasciospongia cavernosa. The structure was proposed on the basis of spectroscopic data and by chemical transformations. The absolute configuration of cacospongionolides 2a-4a was established using the modified Mosher's method. Cacospongionolide E was the most potent inhibitor toward human synovial PLA2, showing higher potency than the reference compound manoalide and exerting no signs of toxicity on human neutrophils. It showed high activity in the Artemia salina bioassay and moderate toxicity in the fish (Gambusia affinis) lethality assay.

A marine natural product inhibitor of kinesin motors

Members of the kinesin superfamily of motor proteins are essential for mitotic and meiotic spindle organization, chromosome segregation, organelle and vesicle transport, and many other processes that require microtubule-based transport. A compound, adociasulfate-2, was isolated from a marine sponge, Haliclona (also known as Adocia) species, that inhibited kinesin activity by targeting its motor domain and mimicking the activity of the microtubule. Thus, the kinesin-microtubule interaction site could be a useful target for small molecule modulators, and adociasulfate-2 should serve as an archetype for specific inhibitors of kinesin functions.

Two new C22 1,2-dioxane polyketides from the marine sponge Acarnus cf. bergquistae

Two new cyclic peroxide-containing polyketide C22 methyl esters, peroxyacarnoic acid methyl esters A and B, 1 and 2, have been isolated from the Red Sea marine sponge Acarnus cf. bergquistae. Both 1 and 2 are proposed to contain a single 1,2-dioxane ring, an eneyne functionality, and a terminal double bond or triple bond, respectively. The structures were elucidated mainly through 1D and 2D NMR spectral analysis.