The absolute configuration of kurospongin,a new furanoterpene from a marine sponge,Spongia sp

Kurospongin (1_~), a new C₂₁ furanoterpene having ichthyotoxic and feeding-deterrent properties has been isolated from a marine sponge,Spongia sp. The gross structure was deduced from the spectroscopic data and the absolute configuration by applying the Horeau method to a derivative prepared by the reaction of1_~with ethylmagnesium bromide.     

Spongiains A-C: Three new spongian diterpenes with ring A rearrangement from the marine sponge Spongia sp.

Spongiains A-C (1–3), the first examples of spongian diterpenes bearing a pentacyclic skeleton composed of a fused 5/5/6/6/5 ring system through ring A rearrangement, together with four new spongian diterpenes, spongiains D-G (4–7), were isolated from the marine sponge Spongia sp.. The structures with absolute configurations of these compounds were elucidated by the methods of NMR, X-ray diffraction and quantum chemical approaches. The hypothetical biogenetic pathways as well as cytotoxic activities of 1–7 were also discussed.     

Halichonadins K and L, new dimeric sesquiterpenoids from a sponge Halichondria sp

Two new structurally unique dimeric sesquiterpenoids, halichonadins K (1) and L (2), were isolated from an Okinawan marine sponge Halichondria sp. The structures of 1 and 2 were elucidated on the basis of spectroscopic analysis including a single crystal X-ray diffraction analysis and chemical conversion. Halichonadins K (1) and L (2) are homodimers of the eudesmane sesquiterpene linked with a piperidine ring through amide bonds. Halichonadin K (1) showed moderate cytotoxicity against KB cells.     

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.     

Halichonadins G-J, new sesquiterpenoids from a sponge Halichondria sp.

Three new dimeric sesquiterpenoids, halichonadins G-I (1-3), and one new eudesmane sesquiterpenoid possessing a 1-phenethyl urea moiety, halichonadin J (4), were isolated from a marine sponge Halichondria sp. Halichonadins G (1) and H (2) are homo-dimers of eudesmane sesquiterpenoid, linked through a methyl 2-{1-(2-amino-2-oxoethyl)ureido}acetate fragment and a 2-hydroxymalonamide fragment, respectively, while halichonadin I (3) is a new hetero-dimer of eudesmane sesquiterpenoid linked through a urea fragment. The structures of 1-4 were elucidated on the basis of spectroscopic data.     

Metachromins L-Q, new sesquiterpenoid quinones with an amino acid residue from sponge Spongia sp.

Six new sesquiterpenoid quinones with an amino acid residue, metachromins L-Q (1-6), have been isolated from an Okinawan marine sponge Spongia sp. The structures and stereochemistry of 1-6 were elucidated on the basis of the spectroscopic data and chemical correlations. Metachromins L (1) and M (2) showed modest cytotoxicity.     

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.     

Pseudoceramines A-D, new antibacterial bromotyrosine alkaloids from the marine sponge Pseudoceratina sp

Bioassay-guided fractionation of the CH(2)Cl(2)/MeOH extract of the Australian marine sponge Pseudoceratina sp. resulted in the purification of four new bromotyrosine alkaloids, pseudoceramines A-D (1-4), along with a known natural product, spermatinamine (5). The structures of 1-5 were determined by spectroscopic methods. Pseudoceramines A (1) and B (2) feature a rare bromotyrosyl-spermine-bromotyrosyl sequence, and pseudoceramine C (3) is the first example of bromotyrosine coupled with an N-methyl derivative of spermidine. Compounds 1-5 were screened for inhibition of toxin secretion by the type III secretion (T3S) pathway in Yersinia pseudotuberculosis. Compounds 2 and 5 inhibited secretion of the Yersinia outer protein YopE (IC(50) = 19 and 6 μM, respectively) and the enzyme activity of YopH (IC(50) = 33 and 6 μM, respectively).     

Jasisoquinolines A and B, architecturally new isoquinolines, from a marine sponge Jaspis sp

Two architecturally new isoquinolines, jasisoquinolines A and B, were isolated from a marine sponge Jaspis sp. as cathepsin B inhibitors. Their structures were determined by a combination of spectroscopic analyses and chemical methods. Both jasisoquinolines A and B inhibit cathepsin B with an IC(50) value of 10 μg/mL.     

Two new spongian diterpene analogues isolated from the marine sponge Acanthodendrilla sp

Abstract

Two new marine natural compounds, 3β-acetoxy-15-hydroxyspongia-12-en (1) and 3-methylspongia-3,12-dien-16-one (2), were isolated from the marine sponge Acanthodendrilla sp., collected in Pulau-Pulau. Compounds 1 and 2 represent new chemical entities of the known spongian diterpene family. Compound 1 is a new 3-acetoxyspongia and compound 2 presents an unreported rearranged 3-methylspongia-3-en. Their structures, including relative configurations, were fully elucidated based on 1D and 2D NMR analyses, as well as HRESTOFMS experiments. No significant bioactivities were found for these compounds. This work reports two new chemical structures, compounds 1 and 2, together with the first isolation of spongian diterpenes from Acanthodendrilla genus.     

Phorbasins G-K: new cytotoxic diterpenes from a southern Australian marine sponge, Phorbas sp

Fractionation of a cytotoxic extract obtained from a southern Australian marine sponge, Phorbas sp., yielded the known diterpenes phorbasins B-F () together with five new members of the phorbasin family, phorbasins G-K (). Structures were assigned to the new phorbasins based on detailed spectroscopic analysis. A preliminary structure activity relationship (SAR) evaluation based on the co-metabolites phorbasins B-K () revealed aspects of the phorbasin pharmacophore.     

Agelasine G, a new antileukemic alkaloid from the Okinawan marine sponge Agelas sp.

A new antileukemic alkaloid, agelasine G (1a), has been isolated from the Okinawan marine sponge Agelas sp. and its structure elucidated to be a bromopyrrole alkaloid containing 9-methyladenine and diterpene moieties on the basis of the spectroscopic data.     

Amphimelibiosides A-F, six new ceramide dihexosides isolated from a Japanese marine sponge Amphimedon sp

Six new ceramide dihexosides, amphimelibiosides A-F (1-6), were isolated from a Japanese marine sponge Amphimedon sp. The structure of amphimelibioside C (3), which is a major component of amphimelibiosides, was determined by 2D NMR techniques, chemical degradation, and a semisynthetic method to be 1-O-[beta-D-glucopyranosyl-(1-->6)-alpha-D-galactopyranosyl]-(2S,3S,4R,6E)-2-[(2'R)-2-hydroxydocosanoyl]-2-amino-6-octadecene-1,3,4-triol. The structures of the other constituents were elucidated by a combination of mass spectra, (1)H NMR, and GC-MS analysis.     

Two new hirsutane-type sesquiterpenoids chondrosterins N and O from the marine fungus Chondrostereum sp.

The marine fungus Chondrostereum sp. was collected from a soft coral Sarcophyton tortuosum from the South China Sea. This fungus was cultured in glucose-peptone-yeast (GPY) medium and the culture broth was extracted with EtOAc. By the method of ¹H NMR pre-screening and tracing the diagnostic proton signals of the methyl groups, two new hirsutane-type sesquiterpenoids, chondrosterins N and O (1 and 2) were isolated from the metabolite extracts. Their structures were elucidated on the basis of MS, 1D and 2D NMR data.     

Halichonic acid,a new rearranged bisabolene-type sesquiterpene from a marine sponge Halichondria sp.

A new compound, halichonic acid (1), was isolated from a marine sponge Halichondria sp., together with (6R,7S)-7-amino-7,8-dihydro-α-bisabolene (2). The structure of 1 was elucidated by spectroscopic analysis and ECD spectrum calculation to be a rearranged bisabolene-type sesquiterpene having a 3-azabicyclo[3.3.1]nonene moiety. Compound 2 was cytotoxic against HeLa cells with an IC₅₀ value of 50?μM, whereas 1 did not show cytotoxicity even at 50?μM. It is possible that 1 is biosynthesized from farnesyl pyrophosphate and glycine, with rearrangement.     

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.     

A new cytotoxic and tubulin-interactive milnamide derivative from a marine sponge Cymbastela sp

[structure: see text] The crude methanol extract of a marine sponge Cymbastela sp. collected in Papua New Guinea was selected for chemical investigation due to its significant cytotoxicity. Fractionation of the extract led to the isolation of jaspamide (1), hemiasterlin (2), milnamide A (3), and a new metabolite, milnamide D (4). The structure was solved by interpretation of NMR and mass spectra data. The cytotoxic and antitubulin activities of milnamide D (4) were evaluated.     

Cyclosmenospongine, a new sesquiterpenoid aminoquinone from an Australian marine sponge Spongia sp.

A new sesquiterpenoid aminoquinone, cyclosmenospongine (1), containing a dihydropyran ring, was isolated from an Australian marine sponge Spongia sp., along with the known metabolites, smenospongiarine, ilimaquinone and smenospongine. The structure of 1 was determined from spectroscopic data.     

Diplopuupehenone, a new unsymmetrical puupehenone-related dimer from the marine sponge Dysidea sp.

A new unsymmetrical puupehenone-related dimer, diplopuupehenone, comprising puupehenone and puupehenol segments, was isolated from the marine sponge Dysidea sp., along with the known metabolites, puupehenone and bispuupehenone. The structure of diplopuupehenone was established from spectroscopic data and by spectroscopic analysis of an acetoxy derivative. Diplopuupehenone showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity with an IC₅₀ value of 8 μM.     

Untenolide A, a new polyketide from an Okinawan marine sponge Plakortis sp.

A new polyketide, untenolide A (1), has been isolated from an Okinawan marine sponge Plakortis species, and the structure was elucidated from spectroscopic data and X-ray analysis. Untenolide A (1) is a new polyketide possessing a fused-pentacyclic skeleton with two hexadecanyl chains.