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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]

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]