New bromotyrosine alkaloids from the marine sponge Psammaplysilla purpurea

Seven new bromotyrosine alkaloids Purpurealidin A, B, C, D, F, G, H and the known compounds Purealidin Q, Purpurealidin E, 16-Debromoaplysamine-4 and Purpuramine I have been isolated from the marine sponge Psammaplysilla purpurea. Their structure was elucidated on the basis of detailed 1D, 2D NMR and MS spectroscopic data. Purpurealidin B, 16-Debromoaplysamine-4 and Purpuramine I exhibited in vitro antimicrobial activities against E. coli, S. aureus, and V. cholerae. In addition, Purpurealidin B and 16-Debromoaplysamine-4 were also active against Shigella flexineri and Salmonella typhi while Purealidin Q was bactericidal only against Salmonella typhi.     

Suberitine A-D, four new cytotoxic dimeric aaptamine alkaloids from the marine sponge Aaptos suberitoides

Suberitine A-D (1-4), four new bis-aaptamine alkaloids with two aaptamine skeleton units, 8,9,9-trimethoxy-9H-benzo[de][1,6]-naphthyridine and demethyl(oxy)-aaptamine, linked through a rare C-3-C-3' or C-3-C-6' σ-bond between the 1,6-naphthyridine rings, together with two known monomers 5 and 6, were isolated from the marine sponge Aaptos suberitoides. Their structures were elucidated using NMR spectroscopy. Compounds 2 and 4 showed potent cytotoxicity against P388 cell lines, with IC(50) values of 1.8 and 3.5 μM, respectively.     

Cytotoxic alkaloids from the marine sponge Thorectandra sp

Three beta-carboline alkaloids, Compound 1, 1-deoxysecofascaplysin A (2), and fascaplysin (3), were isolated from the aqueous and organic extracts of the marine sponge Thorectandra sp. The structures of 1 and 2 were determined on the basis of spectral data. Compound 1 inhibited the growth of MCF-7 (breast) with an IC50 of 5.9 microg/mL while Compound 2 inhibited the growth of MCF-7 as well as OVCAR-3 (ovarian) human tumor cell lines with IC50s of 1.5 and 2.2 microg/mL, respectively.     

Ceratamines A and B, antimitotic heterocyclic alkaloids isolated from the marine sponge Pseudoceratina sp. collected in Papua New Guinea

[structure: see text] Two novel antimitotic heterocyclic alkaloids, ceratamines A (1) and B (2), have been isolated from the marine sponge Pseudoceratina sp., collected in Papua New Guinea. The structures of 1 and 2 were elucidated by analysis of spectroscopic data.     

Dysidavarones A-D, new sesquiterpene quinones from the marine sponge Dysidea avara

Dysidavarones A-D (1-4), four new sesquiterpene quinones possessing the unprecedented "dysidavarane" carbon skeleton, were isolated from the South China Sea sponge Dysidea avara. The structures were established by spectroscopic methods, and the absolute configurations were determined using quantum mechanical calculation of the electronic circular dichroic (ECD) spectrum and exciton chirality CD method. Their cytotoxic activity against four human cancer cell lines and PTP1B inhibitory activity were also evaluated.     

Novel sulfated sesterterpene alkaloids from the marine sponge Fasciospongia sp

Fasciospongines A (1) and B (2), two unusual sulfated sesterterpene alkaloids of an unprecedented structural class, have been isolated from the marine sponge Fasciospongia sp. The structures were elucidated on the basis of spectroscopic analysis. Compounds 1 and 2 displayed potent inhibitory activity to Streptomyces 85E in the hypha formation inhibition (HFI) bioassay.     

Ianthesine E, a new bromotyrosine-derived metabolite from the Great Barrier Reef sponge Pseudoceratina sp

The new compound ianthesine E (1) was isolated from the Great Barrier Reef marine sponge Pseudoceratina sp. along with the known metabolites 11-hydroxyaerothionin (2), aerothionin (3) and 11,19-dideoxyfistularin 3 (4). Structures were determined on the basis of their spectroscopic data. The compounds were tested for inhibition of [(3)H] DPCPX binding to adenosine A(1) receptors in a whole cell binding assay. At 100 microM, aerothionin was the most potent, inhibiting 67% of binding, followed by ianthesine E and 11-hydroxyaerothionin which inhibited 61% of binding, and 11,19-dideoxyfistularin which initiated 51% of binding Ianthesine E (EC(50) 60 microM), aerothionin (EC(50) 42 microM) and 11,19-dideoxyfistularin-3 (EC(50) 2.6 microM) exhibited moderate cytotoxicity against the HeLa cell line.     

New bromopyrrole alkaloids from the marine sponge Agelas sp.

Chemical investigation of the marine sponge Agelas sp. collected from the South China Sea resulted in the isolation of four new dimeric bromopyrrole alkaloids, including hexazosceptrin (1) with a rare cyclohexane-fused-cyclobutane skeleton, agelestes A and B (2–3), the sceptrin analogues without any aminoimidazole substitution, and (9S, 10R, 9′S, 10′R)-nakamuric acid (4), of which the absolute configuration was confirmed for the first time. The structure elucidation and absolute configuration assignments were unambiguously determined via extensive spectroscopic analyses and the comparison of experimental and calculated electronic circular dichroic spectra. Compounds 1 and 4 exhibited moderate antimicrobial activity.     

Syntheses of pseudoceramines A-D and a new synthesis of spermatinamine, bromotyrosine natural products from marine sponges

Herein we report the total syntheses of pseudoceramine A-D (2-5) and spermatinamine (1) isolated from the marine sponge Pseudoceratina sp. Direct acyl substitution of α-hydroxyiminoesters with amine nucleophiles was developed as a key transformation. The synthetic compounds confirm the reported structures and importantly gives access to non-symmetrical spermine based natural products carrying two different bromotyrosine building blocks. Our new synthesis of spermatinamine is two steps shorter and more efficient than the previously reported sequence.     

Halichonadins A-D, new sesquiterpenoids from a sponge Halichondria sp.

A new dimeric sesquiterpenoid with two eudesmane skeletons through a urea linkage, halichonadin A (1), as well as three new eudesmane sesquiterpenoids having a carbamate, an isonitrile, or an amino functionality, halichonadins B (2), C (3), and D (4), respectively, have been isolated from a marine sponge Halichondria sp., and the gross structures and relative stereochemistry of 1-4 were elucidated on the basis of spectral data and chemical means.     

Pyrinodemins B-D, potent cytotoxic bis-pyridine alkaloids from marine sponge amphimedon sp

New bis-pyridine alkaloids, pyrinodemins B-D (1-3), have been isolated together with pyrinodemin A (4) and related 3-alkyl pyridine alkaloids 5-8 from the Okinawan marine sponge Amphimedon sp. and the structures were elucidated from spectroscopic data. Pyrinodemins B-D (1-3) showed potent cytotoxicity, while compounds 5-8 exhibited antimicrobial activity.     

Bromine-containing alkaloids from the marine sponge Penares sp.

Two new unusual alkaloids were isolated from the sponge Penares sp., collected from Viet Nam waters (the South China Sea). The structures of these compounds were established by analysis of 1D, 2D NMR (¹H-¹H COSY, DEPT, HSQC, HMBC, H2BC, and NOE), and MS data. Compound 1 shows moderate cytotoxicity against the human tumor cells HL-60 and HeLa.     

Araiosamines A-D: tris-bromoindole cyclic guanidine alkaloids from the marine sponge Clathria (Thalysias) araiosa

Four new tris-bromoindole cyclic guanidine alkaloids, araiosamines A-D, were isolated from the methanol extract of a marine sponge, Clathria (Thalysias) araiosa, collected from Vanuatu. Their carbon skeletons delineate a new class of indole alkaloids apparently derived from a linear polymerization process involving a carbon-carbon bond formation. Comparison of the structures including the relative configurations suggests a common intermediate containing a dihydroaminopyrimidine moiety capable of undergoing various modalities of conjugate addition to yield unprecedented ring systems.     

Metachromins R--T, new sesquiterpenoids from marine sponge Spongia sp

Three new sesquiterpenoids, metachromins R--T (1--3), have been isolated from an Okinawan marine sponge Spongia sp. The structures and stereochemistry of 1--3 were elucidated on the basis of the spectroscopic data. Metachromins S (2) and T (3) showed modest cytotoxicity.     

Identifying the related compounds using electrospray ionization tandem mass spectrometry: bromotyrosine alkaloids from marine sponge Psammaplysilla purpurea

We have investigated extracts of marine sponge Psammaplysilla purpurea during three collections from Mandapam (Tamil Nadu, India) and Okha (Gujarat, India) and indentified two new bromotyrosine alkaloids, purpurealidin I (7) and J (8) using electrospray ionization tandem mass spectrometry (ESI-MS/MS). This sponge has tremendous chemical diversity of bromotyrosine alkaloids. Here we have used the proteomics approach in identifying related bromotyrosine alkaloids based on the predicated mass fragmentation pattern. The focus is on the examination of detailed product ion spectra of six known compounds that allowed identification of new compounds based on its mass fragmentation pattern. The isotopic pattern of the peaks for protonated molecules indicated the number of bromine atoms present in the molecule. During MS/MS studies, the most prominent product ion peak is for the presence of side chain propane with either free NH(2) or NHMe or Nme(2). The cleavage at C-C bond between oxime-amide carbonyl and amide-phenoxy moiety also gave characteristic product ions. The ESI-MS spectra for all three collections show that the bromotyrosine metabolites vary during different season and also geographical location. Although, some common metabolites were observed during the three collections. Thus, ESI-MS/MS is a method of choice in identifying the related compounds.     

Novel bromotyrosine derivatives that inhibit growth of the fish pathogenic bacterium Aeromonas hydrophila, from a marine sponge Hexadella sp

Three new bromotyrosine derivatives, 11-N-methylmoloka'iamine (1), 11-N-cyano-11-N-methylmoloka'iamine (2), and kuchinoenamine (3), were isolated as antibacterial constituents from a marine sponge Hexadella sp. Their structures were elucidated on the basis of spectral and chemical methods. They exhibited moderate antibacterial activity against the fish pathogenic bacterium Aeromonas hydrophila.     

A new thiodiketopiperzaine from the marine sponge Tedania sp.

Abstract

A new thiodiketopiperzaine, tedanizaine A (1), together with six known ones, were isolated from the marine sponge Tedania sp. Their structures were determined by spectroscopic analyses. The absolute configuration of 1 was established by ECD calculation. Compound 1 was the second example of thiodiketopiperazine bearing a thiazolidine unit. Cytotoxic activities of 1 were also evaluated.     

Pseudoceratins A and B, antifungal bicyclic bromotyrosine-derived metabolites from the marine sponge Pseudoceratina purpurea

Pseudoceratins A (1) and B (2) have been isolated from the marine sponge Pseudoceratina purpurea. Pseudoceratins are unique among the large class of bromotyrosine-derived sponge metabolites with respect to the substitution pattern of aromatic rings and the presence of spiroacetal and oxime ether functional groups as well as an 1,5-diamino-1,5-dideoxy-D-arabitol tether. Pseudoceratins A (1) and B (2) are epimeric differing in the orientation of the tether. Their structures were determined by analysis of spectral data. The rigidity of the compounds arising from their bridged structure gave ROESY/NOESY spectra with many transannular cross-peaks, which allowed the assignment of the relative stereochemistry of 1 and 2 to be established. The d-configuration of the 1,5-diamino-1,5-dideoxyarabitol unit was determined by converting the fragment isolated from the acid hydrolysate to the Mosher's ester and compared the 1H NMR spectrum with those of standard samples. Pseudoceratins exhibited significant antifungal activity against Candida albicans.     

Bistellettazines A-C and bistellettazole A: new terpenyl-pyrrolizidine and terpenyl-imidazole alkaloids from a southern Australian marine sponge, Stelletta sp

Four new alkaloids have been isolated during chemical investigations into a southern Australian marine sponge, Stelletta sp. Detailed spectroscopic analysis, supported by chemical degradation and partial synthesis, permitted structure elucidation of bistellettazines A-C ( 1- 3), the first reported examples of terpenyl-pyrrolizidine conjugates, and bistellettazole A ( 4), a unique cyclic terpenyl-imidazole conjugate. The alkaloids 1- 4 feature unprecedented carbon skeletons that are proposed to share a common convergent biosynthetic origin, arising via the biogenic equivalent of a Diels-Alder addition between two hypothetical polyenyl norsesquiterpene precursors.     

Dihydrohymenialdisines, new pyrrole-2-aminoimidazole alkaloids from the marine sponge Cymbastela cantharella

In our investigation of bioactive marine natural products, we revisited an ethanolic extract of the New Caledonian sponge Cymbastela cantharella. Four new natural compounds (3-6) were isolated and their structural determinations as dihydrohymenialdisine derivatives were achieved by spectral data analysis and chemical conversion. These products did not show any activity in the Polo Like kinase bioassay, demonstrating thus the importance of the unique structure of hymenialdisine, known as an improved kinase inhibitor.