Dysideaprolines A-F and barbaleucamides A-B, novel polychlorinated compounds from a Dysidea species

Chemical investigation of a marine sponge, Dysidea sp., collected at Bararin Island, Philippines, has afforded the novel metabolites 1-6, proline-derived analogues of dysidenin (7). We have termed compounds 1-6 dysideaprolines A-F, respectively. Also isolated were compounds 8 and 9, structural analogues of barbamide (10), a metabolite originally isolated from the cyanobacterium Lyngbya majuscula. We have termed these novel compounds barbaleucamides A (8) and B (9). It is most probable that the compounds presented here are actually derived from a symbiotic cyanobacterium found in close association with the Dysidea sp. Structure elucidation of the isolated metabolites involved high-field 2D NMR spectroscopy including (1)H-(1)H COSY, HSQC, and HMBC.     

Spongian diterpenoids from the sponge Spongia (Heterofibria) sp

Five new (1, 2, 4-6) and one known (3) diterpenoid were isolated from the keratose sponge Spongia (Heterofibria) sp. Structures of these compounds and their absolute configurations were proposed on the basis of X-ray analysis of 1, its CD spectrum, and NMR and MS spectroscopic studies of 1-6. One of the new diterpenoids was shown to be 2(R),3(S),4(S)-3,18-methylene-2-acetoxyspongia-13(16),14-diene (6), possessing a novel carbon skeleton system.     

Bioactive brominated metabolites from the red sea sponge Suberea mollis

Reinvestigation of the Red Sea sponge Suberea mollis afforded two new bromotyrosine-derived alkaloids, subereamollines A (1) and B (2), two new brominated phenolic compounds, subereaphenols B (7) and C (9), and the known compounds aerothionin (3), homoaerothionin (4), 11,19-dideoxyfistularin-3 (5), aeroplysinin-1 (6), and aeroplysinin-2 (8). The structure determination of the isolated compounds was assigned using one- and two-dimensional NMR spectra and HRFABMS data. The antimicrobial and antioxidant activities of the isolated compounds have been evaluated. Aeroplysinin-1 displayed significant antimicrobial activity against S. aureus, P. aerugenosa, and K. pneumoniae. The isolated compounds were examined for their antioxidant activity using a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) solution-based chemical assay. Among the tested compounds, only subereaphenols B and C displayed a significant effect.     

Brominated arginine-derived alkaloids from the red sea sponge Suberea mollis

Investigation of a new collection of the Red Sea sponge Suberea mollis afforded two new brominated arginine-derived alkaloids, subereamines A (1) and B (2), a new brominated phenolic compound, subereaphenol D (3), and the known compounds dichloroverongiaquinol (4), aerothionin (5), and purealdin L (6). The structures of the isolated compounds were assigned using one- and two-dimensional NMR spectra and HRFABMS data. The absolute configurations of subereamines A (1) and B (2) were determined by acid hydrolysis followed by chiral-phase LC-MS. The antimicrobial and antioxidant activities of the isolated compounds have been evaluated. Dichloroverongiaquinol and subereaphenol D displayed significant antimicrobial activity. Using the DPPH TLC autographic rapid screen for free radical scavenging effects, subereaphenol D displayed a significant antioxidant effect. In addition, the cytotoxic activities of the isolated compounds were investigated.     

Batzelline D and isobatzelline E from the indopacific sponge Zyzzya fuliginosa

Two new pyrroloquinoline alkaloids, isobatzelline E (1) and batzelline D (2), together with the known compounds batzelline C (3), isobatzelline C (4), and makaluvamine D (5), were isolated from an Indopacific collection of the marine sponge Zyzzya fuliginosa; the known compounds makaluvamines A (9), H (10), J (7), K (8), and P (6) were obtained from Z. fuliginosa collected in Papua New Guinea. The structures were elucidated by interpretation of 1D (1)H and (13)C NMR spectra and 2D HSQC and HSQC-LR spectra. Compounds 1-10 were isolated because the crude extracts of both Zyzzya species inhibited HIV-1 envelope-mediated cell fusion. However, the inhibition profile observed for the pure compounds 1-10 mirrors that reported for the inhibition of topoisomerase II by other pyrroloquinolines, leaving open the possibility that the activity results from interactions with DNA-modifying enzymes.     

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.     

Halogenated monoterpenes from plocamium costatum and their biological activity1

From the dichloromethane solubles of the temperate red alga Plocamium costatum, one new [1,4-dibromo-2,3,6-trichloro-3, 7-dimethyl-7-octene] (1) and three previously reported polyhalogenated monoterpenes (2-4), and the known phytol derivative 3,7,11,15-tetramethylhexadec-1-en-3-ol (1-phyten-3-ol, 5) were isolated. The structure of 1 was deduced from its spectroscopic data. For compound 3, complete 1H and 13C NMR data are reported for the first time. The CH2Cl2 extract and compounds 3 and 5 deterred settlement of barnacle larvae, suggesting a potential ecological role of these isolates.     

Cytotoxic sterol derivatives from a marine sponge Homaxinella sp

A bioactivity-guided fractionation of a marine sponge Homaxinella sp. has led to the isolation of three new (1-3) highly degraded sterols and four new 6-O-alkylated (6-9) sterols, along with known sterol derivatives. The degraded sterols (1-5) belong to the class incisterols, previously isolated from the marine sponge Dictyonella incisa. Mainly NMR and MS spectroscopic analyses established the gross structures of the new compounds. The relationship between the stereoisomerism of the side chain and HPLC retention time has also been discussed. The compounds were tested against a panel of five human solid tumor cell lines, and especially the degraded sterols (1-4) displayed significant cytotoxicity.     

Suberedamines A and B, new bromotyrosine alkaloids from a sponge Suberea species

Two new cytotoxic bromotyrosine alkaloids, suberedamines A (1) and B (2), have been isolated from an Okinawan marine sponge Suberea sp. The structures were elucidated on the basis of spectroscopic data and chemical means.     

Anthraquinones and betaenone derivatives from the sponge-associated fungus Microsphaeropsis species: novel inhibitors of protein kinases

An undescribed fungus of the genus Microsphaeropsis, isolated from the Mediterranean sponge Aplysina aerophoba, produces two new betaenone derivatives (1, 2) and three new 1,3,6, 8-tetrahydroxyanthraquinone congeners (5-7). The structures of the compounds were established on the basis of NMR spectroscopic and mass spectrometric data and by CD spectroscopy. This is the first report wherein the (1)H and (13)C NMR data of the betaenone congeners are fully and unambiguously assigned on the basis of two-dimensional NMR spectroscopy. Furthermore, we describe the first elucidation of the absolute configuration of 1-(2'-anthraquinonyl)ethanols such as 5 and 6, by quantum chemical calculation of their circular dichroism (CD) and comparison with experimentally measured spectra. Moreover, it was shown that compounds 1, 5, 6, and 7 are inhibitors of PKC-epsilon, CDK4, and EGF receptor tyrosine kinases.