Chlorinated acetylenes from the San Diego sponge Haliclona lunisimilis

The sponge Haliclona lunisimilis from Point Loma, California, contained six known chlorinated acetylenes, previously isolated from the dorid nudibranch Diaulula sandiegensis, and three new metabolites, (1Z,3Z)-1-chlorohexadeca-1,3-diene-5,7-diyne-14-ol, (1Z,3E,9Z)-15-acetoxy-1-chlorohexadeca-5,7-diyne-1,3,9-triene, and (1Z,3E)-14-acetoxy-1-chlorohexadeca-1,3-diene-5,7-diyne. The structures of the new compounds were elucidated by interpretation of spectroscopic data. The relationship between the sponge metabolites and the nudibranch metabolites is discussed.     

A new isoquinoline alkaloid from the marine sponge Haliclona species

Two isoquinoline alkaloids, including the new compound 1, were isolated from the cytotoxic fractions of an aqueous extract of the marine sponge Haliclona sp. The structures of these compounds were established as 1-hydroxymethyl-7-methoxyisoquinolin-6-ol (1) and mimosamycin (2) by conventional spectroscopic methods and by comparison with related compounds. Mimosamycin (2) was the principal cytotoxin with an IC(50) of approximately 10 microg/mL against melanoma and ovarian human tumor cell lines.     

A new antifouling hexapeptide from a Palauan sponge,Haliclona sp

Bioassay-guided fractionation of an extract of the sponge Haliclona sp. provided a known hexapeptide, waiakeamide (1), and a new sulfone derivative (2). The structures of hexapeptides 1 and 2 were elucidated by extensive NMR analyses and the advanced Marfey's method with LC/MS. These compounds showed repellent activity against the blue mussel, Mytilus edulis galloprovincialis.     

Haliclonyne, a new highly oxygenated polyacetylene from the marine sponge Haliclona species

Haliclonyne (1), a new polyacetylene carboxylic acid, has been isolated from the marine sponge Haliclona sp. collected in the Gulf of Eilat. The structure of haliclonyne, a C(47) oxo-octahydroxy-dienetetrayne carboxylic acid, was elucidated by interpretation of NMR and mass spectra of 1 and two of its derivatives.     

Renierosides, cerebrosides from a marine sponge Haliclona (Reniera) sp

Guided by the brine shrimp lethality assay, eight new cerebrosides (1-8) have been isolated from an extract of the marine sponge Haliclona (Reniera) sp. A novel feature of these cerebrosides was the presence of unprecedented amide-linked long-chain fatty acid moieties. The planar structures of the cerebrosides (1-8) were established by 1D and 2D NMR spectroscopic techniques, mass spectrometric analyses, and chemical degradation methods. The isolated compounds did not display cytotoxicity to a panel of five human solid tumor cell lines.     

Hexaprenoid hydroquinones from the sponge Haliclona (aka Adocia) sp

Three new hexaprenoid hydroquinones, adociaquinol (1), adociasulfate 11 (2), and adociasulfate 12 (3), together with the known adociasulfates 2, 4, and 6, were isolated from the marine sponge Haliclona (aka Adocia) sp. The structures of these compounds were elucidated by interpretation of spectroscopic data.     

Haligramides A and B, two new cytotoxic hexapeptides from the marine sponge Haliclona nigra

Bioassay-guided fractionation of a cytotoxic aqueous extract of the sponge Haliclona nigra provided two new cyclic hexapeptides, haligramides A (1) and B (2), in addition to the known peptide, waiakeamide (3). The structures of peptides 1 and 2 were elucidated by extensive NMR analyses and by comparison of their spectral data with those of waiakeamide (3). The identity of haligramide A (1) was confirmed by its oxidative conversion to waiakeamide (3). Further structural confirmation was provided by oxidation of peptides 1, 2, and 3 to the common bis-sulfone derivative 4.     

Gelliusterols A--D, new acetylenic sterols from a sponge, Gellius species.

New acetylenic sterols, gelliusterol A (1, 26,27-bisnorcholest-5-en-23-yn-3 beta,7 alpha-diol), its corresponding 7-ketone, gelliusterol B (2, 26,27-bisnorcholest-5-en-23-yn-3 beta-ol-7-one), and gelliusterols C (4, cholest-5-en-23-yn-3 beta,7-one) and D (5, cholest-5-en-23-yn-3 beta,25-diol-7-one), were isolated from an unidentified species of sponge, Gellius sp. The structures of the steroids were established from spectroscopic data.     

Antifungal alkyl amino alcohols from the tropical marine sponge Haliclona n. sp.

Three new amino alcohols presumably deriving from L-alanine were isolated from the tropical marine sponge Haliclona n. sp. and characterized by 2D NMR, while a fourth amino alcohol was characterized as an acetamide derivative. Relative stereochemistry was deduced from the NMR characteristics of oxazolidinone derivatives and absolute stereochemistry secured by preparation and analysis of an MPA ester. The amino alcohol fraction from Haliclona n. sp. acts as an antifungal agent and inhibits the development of larvae of the ascidian Herdmania curvata.     

Stellettins L and M, cytotoxic isomalabaricane-type triterpenes, and sterols from the marine sponge Stelletta tenuis

Two new isomalabaricane-type triterpenes, stellettins L (1) and M (2), and three new sterols (3-5) were isolated from the marine sponge Stelletta tenuis collected in the South China Sea. Chemical structures were established from spectroscopic data and comparison with known compounds. In addition, spectroscopic data reported for the known sterol 24-methylene-27-methylcholest-5-en-3beta-ol-7-one (6) were revised. Compounds 1 and 2 exhibited significant cytotoxic activity against stomach cancer (AGS) in vitro.     

26,27-cyclosterols and other polyoxygenated sterols from a marine sponge Topsentia sp

Thirty sterols (1-30) were isolated from bioactive fractions of a marine sponge Topsentia sp., of which 16 were new (1, 2, 8, 10-14, 16, 17, 19, 21, 24, 25, 27, and 30). They were characterized as sterols with 10 different side chains and as having various functionalities including 5alpha,8alpha-epidioxy (1-9), 5alpha,6alpha-epoxy-7-ol (10-15), 5,8-dien-7-one (24-28), 5-en-3beta-ol (29), and 1(10-->6)abeo-5,7,9-triene-3alpha,11alpha-diol (30) units and included polyoxygenated sterols (16-23). One of the key features of these new sterols is the presence of the (24R,25R,27R)-26,27-cyclo-24,27-dimethylcholestane side chain, whose absolute stereochemistry was defined by an acid-catalyzed ring-opening method and by comparison with the four synthetic isomers of known absolute stereochemistry. The occurrence of several known fungal sterols and relevant new sterols in this sponge suggested their possible origin from symbiotic fungi. Selected compounds were tested against a panel of five human solid tumor cell lines and displayed moderate to marginal cytotoxicity.     

5,6:8,9-diepoxy and other cytotoxic sterols from the marine sponge Homaxinella sp

Four new (1, 2, 4, and 5) and 14 known (3 and 6-18) polyoxygenated sterols have been isolated from the MeOH extract of the marine sponge Homaxinella sp. by bioactivity-guided fractionation. The planar structures of the sterols were established by 1D and 2D NMR and MS spectroscopic analysis. 5,6:8,9-Diepoxy sterols (1-3) were isolated from a marine organism for the first time. The isolated sterols were tested against a panel of five human solid tumor cell lines and exhibited varying degrees of cytotoxicity.     

Novel cytotoxic oxygenated C29 sterols from the Colombian marine sponge Polymastia tenax

Three new sterols, 5alpha,6alpha-epoxy-24R-ethylcholest-8(14)-en-3beta,7alpha-diol (1), 5alpha,6alpha-epoxy-24R-ethylcholest-8-en-3beta,7alpha-diol (2), and 3beta-hydroxy-24R-ethylcholesta-5,8-dien-7-one (3), have been isolated from the marine sponge Polymastia tenax, collected in the Colombian Caribbean, and their structures established on the basis of extensive NMR and MS studies. Compounds 1 and 2 showed antiproliferative activity toward A-549, HT-29, H-116, MS-1, and PC-3 tumor cells in the range 0.5-10 microg/mL.     

Cyclohaliclonamines A-E: dimeric, trimeric, tetrameric, pentameric, and hexameric 3-alkyl pyridinium alkaloids from a marine sponge Haliclona sp

A mixture of cyclohaliclonamines A-E (1-5), novel dimeric, trimeric, tetrameric, pentameric, and hexameric 3-alkylpyridinium alkaloids, was obtained from an Okinawan sponge Haliclona sp. Cyclohaliclonamines C-E are the first tetrameric, pentameric, and hexameric 3-alkylpyridinium alkaloids from natural sources. The structure determination of cyclohaliclonamines is discussed in detail.     

New polyhydroxy sterols: proteasome inhibitors from a marine sponge Acanthodendrilla sp

Seven new polyhydroxylated sterols, as well as the known agosterols A, C, and D2 (8-10), were isolated from a marine sponge Acanthodendrilla sp. as proteasome inhibitors. Their structures were elucidated on the basis of their spectral data, and they were characterized as agosterol congeners, which had been initially isolated from a marine sponge Spongia sp. and reported to reverse multidrug resistance in tumor cells. Among them, agosterol C (9) most strongly inhibited chymotrypsin-like activity of the proteasome with an IC50 value of 10 microg/mL.     

(2R,3R,7Z)-2-Aminotetradec-7-ene-1,3-diol, a new amino alcohol from the caribbean sponge Haliclona vansoesti

The Caribbean marine sponge Haliclona vansoesti was found to contain a high amount (5% dry wt) of a new analogue of 4-sphingenine, (2R,3R, 7Z)-2-aminotetradec-7-ene-1,3-diol (1). Its structure was determined by detailed spectroscopic analysis. The relative configuration was deduced from the NMR data of the corresponding acetonide 5, while the absolute configuration was secured via protection of the primary alcohol and amino groups, and esterification of the secondary alcohol with Mosher's reagent.     

Bioactive sterols from the starfish Certonardoa semiregularis

Thirteen new polyhydroxysterols (1-5, 7-12, 14, 15) and two known polyhydroxysterols (6, 13) were isolated from the brine shrimp active fraction of the starfish Certonardoa semiregularis. The structures were determined on the basis of spectral analysis and chemical derivatization. These compounds displayed considerable cytotoxicity against a small panel of human solid tumor cell lines. These compounds were also evaluated for antibacterial activity against 20 clinically isolated strains. Most of the compounds showed weak antibacterial activity against Streptococcus pyogenes 308A, Pseudomonas aeruginosa 1771, and Pseudomonas aeruginosa 1771M.     

Polyhydroxylated sterols from the octocoral Dendronephthya gigantea

Two new polyhydroxylated sterols, dendronesterols A (1) and B (2), have been isolated from the octocoral Dendronephthya gigantea. The structures of 1 and 2 were proposed on the basis of extensive NMR experiments. Compound 2 was found to be weakly cytotoxic toward L1210 cells.     

Cytotoxic sterols and saponins from the starfish Certonardoa semiregularis

Eleven new polyhydroxysterols (1-11) and eight new saponins (12-19) were isolated from the brine shrimp active fraction of the starfish Certonardoa semiregularis. The structures were determined on the basis of spectral analysis and chemical derivatization. The structural variations of these compounds are due to the hydroxylation pattern of the sterol nucleus, the functionalization of the side chain, or the nature and location of the saccharide moiety. These compounds displayed considerable cytotoxicity against a small panel of human solid tumor cell lines.     

Mirabamides E-H, HIV-inhibitory depsipeptides from the sponge Stelletta clavosa

Four new depsipeptides, mirabamides E-H (1-4), and the known depsipeptide mirabamide C (5) have been isolated from the sponge Stelletta clavosa, collected from the Torres Strait. The planar structures were determined on the basis of extensive 1D and 2D NMR and HRESIMS. The absolute configurations were established by the advanced Marfey's method, NMR, and GC-MS. The four new compounds all showed strong inhibition of HIV-1 in a neutralization assay with IC(50) values of 121, 62, 68, and 41 nM, respectively.