Swinholide J, a Potent Cytotoxin from the Marine Sponge Theonella swinhoei

In our ongoing search for new pharmacologically active leads from Solomon organisms, we have examined the sponge Theonella swinhoei. Herein we report the isolation and structure elucidation of swinholide A (1) and one new macrolide, swinholide J (2). Swinholide J is an unprecedented asymmetric 44-membered dilactone with an epoxide functionality in half of the molecule. The structural determination was based on extensive interpretation of high-field NMR spectra and HRESIMS data. Swinholide J displayed potent in vitro cytotoxicity against KB cells (human nasopharynx cancer) with an IC50 value of 6 nM

New genus and species of lithistid demosponges from submarine caves in Nuku Hiva (Marquesas Islands) and Tahiti Iti (Society Islands), French Polynesia

Lithistid demosponges are well known from limestone caves of karstic origin in the Mediterranean Sea. However, they have never been reported from submarine caves of volcanic origin in the South Pacific. Here, we describe and provide DNA barcodes for four new lithistid demosponges including one new genus. All species grew on basaltic rocks inside lava tubes on Nuku Hiva Island (Marquesas Islands) and Tahiti Iti peninsula on Tahiti Island (Society Islands) in French Polynesia. Three of the species have rhizoclone desmas as choanosomal skeletons and belong to the family Scleritodermidae (Microscleroderma miritatarata sp. nov. and Microscleroderma lava sp. nov.) and Siphonidiidae (Gastrophanella basaltica sp. nov.). The new genus Levispongia gen. nov. belongs to the family Corallistidae. The new species Levispongia meyeri gen. nov. sp. nov. has dicranoclone desmas, complex dichotrianes with strongly spinose upper surfaces of the cladome and microstyles as the only microscleres. Phylogenetic relationships of these new species are discussed and compared with other material from the Caribbean and Central to the West Pacific Ocean

Sporochartines A-E, A New Family of Natural Products from the Marine Fungus Hypoxylon monticulosum Isolated from a Sphaerocladina Sponge

Four new sporochartines B-E were isolated from the marine fungus Hypoxylon monticulosurn CLL-205, isolated from a sponge belonging to the Sphaerocladina order and collected in Tahiti coast. Sporochartine A (1), the first representative of this family was previously isolated from the same fungus. The structures of sporochartines B-E were elucidated using 1D and 2D NMR, HRMS and IR data. Their configurations were established according to ROE correlations and comparison with the absolute configuration of sporochartine A (1) previously obtained from X-ray analysis. Sporochartines A-D (2-4) may be derived from endo Diels-Alderase type catalysis and sporochartine E (5) from an exo Diels-Alderase catalysis. The spatial conformation of sporochartines drastically influences the results of the cytotoxic bioassay against HCT-116, PC-3, and MCF-7 human cancer cell lines

New isomalabaricane derivatives from a new species of Jaspis sponge collected at the Vanuatu Islands

Six new cytotoxic isomalabaricane-type triterpenoids and nortriterpenoids with a 3 alpha-acetoxy group were isolated, along with the known globostellatic acids B and C, from the marine sponge Jaspis sp. collected at Vanuatu Island. The structures were determined by 2D NMR data and by comparison with spectral data of known related compd

New Sulfur-Containing Polyarsenicals from the New Caledonian Sponge Echinochalina bargibanti

Arsenicin A (C3H6As4O3) was isolated from the New Caledonian poecilosclerid sponge Echinochalina bargibanti, and described as the first natural organic polyarsenic compound. Further bioguided fractionation of the extracts of this sponge led us to isolate the first sulfur-containing organic polyarsenicals ever found in Nature. These metabolites, called arsenicin B and arsenicin C, are built on a noradamantane-type framework that is characterized by an unusual As-As bonding. Extensive NMR measurements, in combination with mass spectra, enabled the assignment of the structure for arsenicin B (C3H6As4S2) as 2. The scarcity of arsenicin C and its intrinsic chemical instability only allowed the collection of partial spectral data, which prevented the full structural definition. After the extensive computational testing of several putative structures, structure 3 was inferred for arsenicin C (C3H6As4OS) by comparing the experimental and density functional theory (DFT)-calculated H-1 and C-13 NMR spectra. Finally, the absolute configurations of 2 and 3 were determined with a combined use of experimental and time-dependent (TD)-DFT calculated electronic circular dichroism (ECD) spectra and observed specific rotations. These findings pose great challenges for the investigation of the biosynthesis of these metabolites and the cycle of arsenic in Nature. Arsenicins B and C showed strong antimicrobial activities, especially against S. aureus, which is comparable to the reference compound gentamycin

Phosphated and sulfated marine polyhydroxylated steroids from the starfish Tremaster novaecaledoniae

Beside tremasterols A-C, the first phosphated steroid glycosides to be found from a natural source, the starfish Tremaster novaecaledoniae contains nine more novel steroid constituents. One, is related to the previous tremasterols by having the same 6-O-phosphated function. A second group of 4 compds. possesses the same 3,6-disulfated 3β,6α-(22R)-trihydroxycholestane structure, differing by the presence of the Δ9(11) double bond in 2 compds. and by the acetate conjugation of the 22-hydroxyl group in the 2 other compds. The remaining 4 compds. are highly hydroxylated steroids, including one that features the cis A/B ring junction, never encountered before among steroids derived from starfishes

Callipeltin A, an Anti-HIV Cyclic Depsipeptide from the New Caledonian Lithistida Sponge Callipelta sp

Callipeltin A is a cyclic depsidecapeptide from a shallow water sponge of the genus Callipelta (order Lithistida), collected in the waters off New Caledonia. The structure of callipeltin A, which possesses the N-terminus blocked with a b-hydroxy acid, and the C-terminus lactonized with a threonine residue, was detd. by interpretation of spectral data, chem. degrdn., and evaluation of the amino acids obtained by acid hydrolysis. Along with four common L-, one D-, and two N-Me amino acids, it contains three new amino acid residues: b-methoxytyrosine (bOMeTyr), (2R,3R,4S)-4-amino-7-guanidino-2,3-dihydroxyheptanoic acid (AGDHE), and (3S,4R)-3,4-dimethyl-L-glutamine. Callipeltin A (1) has been found to protect cells infected by human immunodeficiency (HIV) virus