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A new diacylguanidine, actinofide (1), has been isolated from the marine mollusk Actinocyclus papillatus. The structure, exhibiting a guanidine moiety acylated by two terpenoid acid units, has been established by spectroscopic methods and secured by synthesis. Following this, a series of structural analogues have been synthesized using the same procedure. All of the compounds have been evaluated in vitro for the growth inhibitory activity against a variety of cancer cell lines.

Two new prenylgermacrane-type diterpenoids, lobophytumins A and B (1 and 2), two new prenyleudesmane-type diterpenoids, lobophytumins C and D (3 and 4), and two new spatane-type diterpenoids, lobophytumins E and F (5 and 6), were isolated from the Hainan soft coral Lobophytum crista turn Tixier-Durivault. Their structures, including relative configuration, were elucidated by detailed analysis of spectroscopic data and by comparison with related known compounds. In addition, the absolute configuration of lobophytumin C (3) was tentatively assigned by comparing its specific rotation with that of the closely related model compound (-)-beta-selinene (8). On the basis of biogenetic considerations, the absolute configurations of lobophytumins A, B, and D F were also tentatively suggested. This is the first report of spatane-type diterpenoids from a soft coral source. The present work supports Faulkner's proposal of prenylgermacrene as the precursor of many diterpenes. In a bioassay, lobophytumins C and D (3 and 4) showed weak in vitro cytotoxicities against the tumor cell lines A-549 and HCT-116.

Chemical investigation of the lipophilic extract of the Antarctic soft coral Alcyonium grandis led us to the finding of nine unreported sesquiterpenoids, 2-10. These molecules are members of the illudalane class and in particular belong to the group of alcyopterosins, illudalanes isolated from marine organisms. The structures of 2-10 were determined by interpretation of spectroscopic data. Repellency experiments conducted using the omnivorous Antarctic sea star Odontaster validus revealed a strong activity in the lipophilic extract of A. grandis against predation.

The Mediterranean dorid nudibranch Peltodoris atromaculata that had been collected while feeding on Haliclona fulva was shown to sequester long-chain fulvinol-like polyacetylene metabolites (compounds 2–5) from the prey. They were isolated along with previously reported bromorenierins from the diethyl ether extracts of both the mollusk and the sponge. Their structures were elucidated by NMR spectroscopy and tandem FABMS analysis. Compound 5 exhibited in vitro growth inhibitory effects against the SKMEL-28 melanoma cell line.

Petroformynes are unusual metabolites contained in the Mediterranean sponge Petrosia ficiformis. The structure and absolute stereochemistry of the most abundant of these compounds, which display long unbranched alkyl chains, have only recently been rigorously proven. The structures of twelve minor compounds are now reported, providing a better understanding of the chemistry of P. ficiformis. In addition, complete spectroscopic characterization of eleven partial structures (a-k) frequently contained in P. ficiformis metabolites is provided as an aid to future structure elucidation among compounds of this type.

This first chemical study of the sacoglossan mollusk Thuridilla splendens from Mooloolaba, South East Queensland, has resulted in the isolation of three new metabolites, thuridillins D-F (1-3), and one known metabolite, thuridillin A (4). Thuridillin D (1) was isolated by conventional flash chromatography on silica gel, while a mixture of thuridillins E (2) and F (3) was obtained by PTLC on AgNO(3)-impregnated silica gel. Thuridillins D-F were determined to be structurally related to thuridillin B (5); 1 possessed a hydroxy group at C-11, and 2 and 3 were Δ(10,11)- and Δ(11,12)-isomers, respectively. HSQC-HECADE NMR data, together with conformational analysis, NOESY experiments, and (1)H-(1)H coupling studies enabled assignment of the individual relative configurations of the epoxylactone, the 2,5-diacetoxy-2,5-dihydrofuran, and cyclohexyl moieties within thuridillin D (1).

Four diterpenes, tritoniopsins A-D (1-4), have been isolated from the South China Sea nudibranch Tritoniopsis elegans and its prey, the soft coral Cladiella krempfi. They display an unprecedented pyran ring in the cladiellane framework, thus representing a novel cladiellane-based diterpene family. Their structures have been mainly characterized by NMR and mass spectrometric techniques, whereas the relative configuration of compound 1 was secured by X-ray analysis. Antiproliferative assays on tumor and nontumor cell lines have been carried out for the main metabolite, tritoniopsin B (2).

A series of nine casbane diterpenes, compounds 5-13, exhibiting either cis or trans ring junctions were isolated from the Hainan soft coral Sinularia depressa. The structures of this group of compounds, the basic member of which was named depressin (5), were established by detailed spectroscopic analysis. In addition, the absolute configuration of the main metabolite, 10-hydroxydepressin (7), and of its epimer, 1-epi-10-hydroxydepressin (8), was determined by a combination of conformational analysis and the modified Mosher's method. A stereochemical relationship between all isolated molecules was investigated by analyzing their circular dichroism profiles. Antiproliferative and antibacterial activities of the depressins were also evaluated.

Three novel fatty acid derivatives (1-3), containing one or two butenolide moieties, were isolated from the Caribbean gorgonian Pterogorgia anceps and chemically characterized by spectroscopic methods and comparison with known compounds. The new molecules were structurally related to ancepsenolide (4), a typical metabolite from Pterogorgia species, which was not detected in this collection of P. anceps.

4 páginas., This paper reports the chemical study of a sample of Fasciospongia sp. collected along the Atlantic Portuguese coast. Three new isomeric furanosesquiterpenes, isomicrocionin-3 (1), (−)-microcionin-1 (2), and (−)-isomicrocionin-1 (3), were isolated along with the known (−)-ent-pallescensin A (4) and (−)-pallescensin-1 (5) from the ethyl acetate-soluble portion of the methanolic extract. The structures of the new compounds were elucidated by extensive spectroscopic studies. (−)-Microcionin-1 (2) tested positive against several Gram-negative bacteria.

Five new polar steroids, polyhydroxysterols 2-5 and the glycoside leviusculoside J (7), were isolated, along with the previously known compounds 1, 6, 8, and 9, from the alcoholic extract of the Far Eastern starfish Henricia leviuscula. The structures of novel compounds were elucidated by interpretation of spectral data (mainly 2D-NMR), and the stereochemistry of chiral centers in the side chain of sterols 2 and 3 was determined by using J-based configuration analysis and the modified Mosher's method. Steroids 1, 3, 6, 7, and 9 showed moderate hemolytic activity in the mouse erythrocytes assay.

A series of isocyanides, compounds 4-11, including diterpenes never before found in Phyllidiid nudibranchs, have been isolated from a Chinese population of the nudibranch Phyllidiella pustulosa. Three new sesquiterpenes (8, 10, and 11), with eudesmane, guaiane, and bisabolane skeletons, respectively, have been characterized by spectral methods and chemical comparison with known related molecules. The absolute stereochemistry of the major metabolite, the isocyanide 8, an enantiomer of the known sponge metabolite stylotelline (12), has also been determined.

The ethereal extract of the Antarctic gorgonian Dasystenella acanthina was found to contain three main nonpolar and relatively transient sesquiterpene metabolites (1-3), which were isolated and submitted to spectral analysis. Two of them were identified as the previously reported compounds trans-beta-farnesene (1) and isofuranodiene (3), whereas the third metabolite, the furanoeudesmane 2, was unknown. The structure elucidation of this new sesquiterpene was solved mainly on the basis of its spectral properties and correlation with known compounds.

Five novel polyacetylenes (5-9) were isolated from two different populations of the sponge Petrosia ficiformis collected in the Mediterranean Sea and the Atlantic Ocean. Their structures were established by extensive NMR analysis and by comparison with known petroformynes.