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Dictyoneolone ( 1 ), a new secosteroid was isolated from a Dictyonella sp. sponge collected from Gageo-do, Korea. Based upon the results of combined spectroscopic analyses, the structure of this compound was determined to possess a highly unusual B/C ring juncture-defused moiety. The configurations of 1 were determined by a combination of proton-proton couplings and NOESY analyses. Dictyoneolone exhibited weak cytotoxicity against the K562 and A549 cancer cell lines. [ABSTRACT FROM AUTHOR]

Twelve previously undescribed polyketide derivatives, heterocornols A-L, and seven known analogues were isolated from a culture of the fungus Pestalotiopsis heterocornis associated with sponge. Their structures were elucidated by a comprehensive spectroscopic data analysis and CD Cotton effects. These compounds were evaluated for cytotoxic and antibacterial activities in vitro . Among them, heterocornols A-C, F-H, methyl-(2-formyl-3-hydroxyphenyl)propanoate, agropyrenol, and vaccinol G exhibited cytotoxicities against four human cancer cell lines with IC 50 values 15–100 μM, and they also showed antibacterial activities against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with MIC values ranging from 25 to 100 μg/mL. Moreover, compounds heterocornol C, heterocornol G, agropyrenol, and vaccinol G showed weak antifungal activities against Candida parapsilosis and Cryptococcus neoformans with MIC values 100 μg/mL. [ABSTRACT FROM AUTHOR]

Plakortinic acids A (2) and B (3), two polyketide endoperoxides with a bicyclo[4.2.0]octene unit, were isolated as minor constituents from the sponge–sponge symbiotic association Plakortis halichondrioides–Xestospongia deweerdtae, along with known epiplakinic acid F (1). The structures of the mixture of two inseparable compounds were determined by spectroscopic analysis. Screening for cytotoxic activity of the mixture against two human tumor cell lines revealed that these compounds are very active at sub-micromolar concentration. [ABSTRACT FROM AUTHOR]

Two new highly acetylated steroids, named dysiroid A ( 1) and dysiroid B ( 2), together with a known compound ( 3) were isolated from the marine sponges Dysidea sp. The chemical structures of 1 and 2 were elucidated by spectroscopic analyses including 1D and 2D NMR experiments and high-resolution electrospray impact mass spectroscopy. Their in vitro antimicrobial activities against a panel of bacterial strains were evaluated. Compounds 1 and 2 showed potent activity against some of the strains with minimum inhibitory concentrations ranging from 4 to 8 μg mL−1. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Halichonic acid (1), was isolated from a marine sponge Halichondria sp. • 1 Has a novel 3-azabicyclo[3.3.1]nonene moiety. • The absolute configuration of 1 was determined by ECD experiment. • 1 May be formed from farnesyl pyrophosphate and glycine, with rearrangement. Abstract A new compound, halichonic acid (1), was isolated from a marine sponge Halichondria sp. , together with (6 R ,7 S)-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 IC 50 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. [ABSTRACT FROM AUTHOR]

Bioassay-guided fractionation of the extract of the rare deep-sea marine sponge Pleroma sp. afforded seven new linear acetylenes, yakushynols A–F ( 1 – 6 ) and neopetroformyne E ( 7 ). The structures of 1 – 7 were determined by a combination of the analysis of spectroscopic data and chemical derivatization. Compounds 1 – 6 are the first examples of the sponge-derived acetylenes of the size of duryne with oxidation at the sixth carbon from the terminus. Compounds 1 – 5 and 7 exhibited moderate cytotoxic activity. A biosynthetic route of neopetroformyne A was inferred from the structural transition among sponge-derived linear acetylenes. [ABSTRACT FROM AUTHOR]

Two new bromotyrosine alkaloids, tyrokeradines G ( 1 ) and H ( 2 ), have been isolated from an Okinawan marine sponge of the order Verongida. The structures of 1 and 2 were elucidated on the basis of spectroscopic data. Tyrokeradine G ( 1 ) is the first bromotyrosine alkaloid possessing a β-alanine unit, while tyrokeradine H ( 2 ) is a rare bromotyrosine alkaloid possessing a N -substituted pyridinium ring. Tyrokeradines G ( 1 ) and H ( 2 ) showed antifungal activity. [ABSTRACT FROM AUTHOR]

Twostructurally unique dimeric bromopyrrole alkaloids, agelamadinsA (1) and B (2), were isolated from a marinesponge Agelassp. Agelamadins A (1)and B (2) have a structure consisting of an agelastatin-liketetracyclic moiety and an oroidin-like linear moiety in common. Thestructures of 1and 2were elucidated onthe basis of spectroscopic analysis. The antimicrobial activity andcytotoxicity of agelamadins A (1) and B (2) were evaluated. [ABSTRACT FROM AUTHOR]