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Two marine sponges of the genus Monanchora (Poecilosclerida, Crambeidae) have been found to contain new polycyclic guanidine alkaloids bearing the (5,6,8b)-triazaperhydroacenaphthylene skeleton. Their structures have been determined by detailed spectroscopic analysis. Dehydrobatzelladine C (1) has been isolated from M. arbuscula and crambescidins 359 (2) and 431 (3) from M. unguiculata. The chemotaxonomic implications of these findings are discussed.

Eight new tetramic acid glycosides named rubrosides A−H have been isolated from the marine sponge Siliquariaspongia japonica. Their structures were elucidated on the basis of spectral data as tetra...

A detailed analysis of the chemical constituents of a Caribbean specimen of Aiolochroia crassa was performed. Five brominated products (1 -5) were isolated and one of these was a new bromotyrosine metabolite. The structure of the new compound 1 has been established from spectral studies. Compounds 1 and 2, which are the major brominated metabolites and have not been previously identified in any Aiolochroia species, could be usefully employed as chemotaxonomic markers.

The Micronesian sponge Oceanapia sp. afforded three pyridoacridine alkaloids: the known compounds kuanoniamine C (1) and kuanoniamine D (2), as well as the new N-deacyl derivative (3) of the kuanoniamines. Compounds 1 and 2 exhibited insecticidal activity toward neonate larvae of the polyphagous pest insect Spodoptera littoralis (LC50 of 156 and 59 ppm, respectively), when incorporated into artificial diet. Both compounds also showed toxicity in the brine shrimp lethality test with a LC50 of 37 micrograms/mL (compound 1) and 19 micrograms/mL (compound 2), respectively. The N-deacyl derivative did not show any remarkable effect in both bioassays. Cytotoxcity of the alkaloids was studied in vitro, using two human cell lines. The new derivative (3) appeared to be active in the same range of concentrations as kuanoniamine C (1) and D (2). The IC50 of 3 was 1.2 micrograms/mL toward HeLa cells and 2.0 micrograms/mL toward MONO-MAC 6 cells. In receptor binding assays compound 2 showed affinity to A1- and A2A-adenosine receptors with Ki values of 2.94 and 13.7 microM, respectively. Compound 1 was less active than compound 2, whereas compound 3 showed no affinity toward adenosine receptors. In addition, compounds 1-3 exhibited moderate affinity to benzodiazepine binding sites of GABAA receptors.

Fractionation of the MeOH extract of the sponge Plakortis sp. collected around the Amirantes Islands yielded four novel polyketides (4−7). The structures have been established by a detailed highfield 2D NMR study.

Ten new steroidal sulfates, acanthosterol sulfates A-J (1-10), have been isolated from a marine sponge, Acanthodendrilla sp., collected in western Japan. Acanthosterol sulfates I and J (9 and 10) showed antifungal activity against the yeast Saccharomyces cerevisiae A364A and its mutants at 0.1 mg/disk.

In this first report on the chemistry of the sponge Stylissa caribica, two known bromopyrrole metabolites and a new compound, N-methyldibromoisophakellin (1), were isolated and identified. The structure of 1 was determined using spectroscopic methods and the computer program Cocon. N-Methyldibromoisophakellin (1) was shown to be the only secondary metabolite in Stylissa caribica that, at its natural concentration, is active as a feeding deterrent against a common omnivorous reef fish.

Kalihinene-A [17] and kalihinene-B [18] two new toxic isocyano diterpenes have been isolated from a Seychelles specimen of the marine sponge Acanthella cavernosa. Their structures were elucidated by interpretation of their spectral properties. The chemotaxonomic value of these secondary metabolites is discussed.

Seven cytotoxic 3-alkylpyridine alkaloids, hachijodines A-G, have been isolated from two marine sponges of the genera Xestospongia and Amphimedon. Their structures were determined on the basis of spectral data. These alkaloids are moderately cytotoxic against P388 murine leukemia cells with IC(50) values of 1.0-2.3 microg/mL.

[reaction: see text] A screening program designed to find new antiinflammatory agents has identified the sponge meroterpenoid pelorol (1) as an in vitro activator of the inositol-5-phosphatase SHIP. Pelorol (1) and several functional group analogues have been synthesized from sclareolide (4).

Structurally unique new sesquiterpenoid quinones dactyloquinone A (1) and B (2), each possessing a dihydropyran moiety, were isolated from an Okinawan sponge Dactylospongia elegans, along with known sesquiterpenoid quinones. The structures of these compounds were determined by spectroscopic analysis.

Two sponges of the genus Hyrtios have been found to contain new sesquiterpene/quinones identified by detailed spectroscopic analysis. Four new compounds with a 4,9-friedodrim-3-ene skeleton [hyrtiophenol (2), 5-epihyrtiophenol (3), 18-hydroxy-5-epihyrtiophenol (4), and 18-hydroxyhyrtiophenol (5)] were isolated from Hyrtios sp. (Seychelles Islands) along with isospongiaquinone (1). Moreover, the new compound 21-hydroxy-19-methoxyarenarone (8), which bears the 4, 9-friedodrim-4(15)-ene skeleton, was isolated from Hyrtios tubulatus (Curaçao) along with arenarol (6) and 5-epiilimaquinone (7). Assignment of the (13)C NMR signals of four types of 4, 9-friedodrimene skeletons found in sponges is presented.

Aurantosides D-F (4-6), new polyene tetramic acids comprising an N-trisaccharide unit, have been isolated from the marine sponge Siliquariaspongia japonica. Their structures were determined by spectral and chemical methods. A reinvestigation of NMR data of the previously isolated aurantosides A and B led to revision of the geometry of the terminal double bond. Aurantosides exhibit potent antifungal activity against Aspergillus fumigatus and Candida albicans.

Geodiamolides J-P (11-17) and R (19), eight new cyclic depsipetides, have been isolated from the marine sponge Cymbastela sp. collected in Papua New Guinea. The serine residue in geodiamolides L-P (13-17) and R (19) has not been previously found in this family of compounds.

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

Analysis of the Philippine marine sponge Xestospongia ashmorica afforded four new manzamine congeners 1-4 and four known compounds 5 and 7-9. Compound 1 is the 6-deoxy derivative of manzamine X, while 2-4 are the N-oxides of manzamine J (5), 3,4-dihydromanzamine A (6), and manzamine A (7), respectively. The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic (1H, 13C, COSY, 1H-detected direct, and long-range 13C-1H correlations) and mass spectrometric (EI, FAB-MS, and electrospray ionization) data. Alkaloid N-oxide structures were confirmed by conversion to the corresponding tertiary bases by reduction with Zn/HCl. This is the first report of the occurrence of bioactive manzamine N-oxides in marine sponges. Compound 7 exhibited insecticidal activity toward neonate larvae of the polyphagous pest insect Spodoptera littoralis (with an ED50 of 35 ppm) when incorporated in artificial diet and offered to larvae in a chronic feeding bioassay. Compound 7 was also active against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus. Cytotoxicity was studied in vitro using L1578y mouse lymphoma cells. From the alkaloids studied, the N-oxides 3 and 4 were the most active (ED50 = 1.6 micrograms/mL) followed by compound 7 (ED50 = 1.8 micrograms/mL).

Kalihinene-A [17] and kalihinene-B [18] two new toxic isocyano diterpenes have been isolated from a Seychelles specimen of the marine sponge Acanthella cavernosa. Their structures were elucidated by interpretation of their spectral properties. The chemotaxonomic value of these secondary metabolites is discussed.

A C(14) acetylenic acid has been isolated as an antimicrobial principle from a marine sponge Oceanapia sp. Its structure was determined on the basis of spectral data.

Four new purine analogues (nigricines 1 – 4) have been isolated from the Indonesian marine sponge Petrosia nigricans. The structures were elucidated by extensive 2D-NMR spectroscopic experiments and mass spectrometry.

An investigation of the sponge Suberea mollis collected at the Egyptian Red Sea coast afforded a new cytotoxic and antimicrobial dibrominated phenol, subereaphenol A (1), together with the previously reported compounds 2-(3′,5′-dibromo-2′-hydroxy-4′-methoxyphenyl)acetamide (2), dibromoverongiaquinol (3), bromochloroverongiaquinol (4), and 2-(3′,5′-dibromo-4′-ethoxy-1′-hydroxy-4′-methoxy-2′,5′-cyclohexadien-1-yl)acetamide (5). The structure of the compounds was determined by a combination of 1D and 2D NMR techniques and High-resolution mass spectral determinations. Complete and new NMR data for the known compounds has been reported. The cytotoxic and the antimicrobial activities of the compounds are reported.