Cytotoxic Oxygenated Steroids from the Soft Coral Nephthea erecta.

A new 10-demethylated steroid, nephtheasteroid A (1), a new 19-oxygenated steroid, nephtheasteroid B (2) as well as five known steroids 3-7 were isolated from the organic extract of a Taiwanese soft coral Nephthea erecta. The structure was determined by means of IR, MS, and NMR techniques. Among these metabolites, 1 is rarely found in steroids possessing a 19-norergostane skeleton.

New nitrogenous bisabolene-type sesquiterpenes from a formosan sponge Axinyssa sp.

Chemical investigation of a Formosan sponge Axinyssa sp. has led to the isolation of five nitrogenous bisabolene-type sesquiterpenes 1-5, including two new compounds axinysalines A (1) and B (2). The structures of new compounds were elucidated by analysis of high resolution (HR)-MS and two dimensional (2D)-NMR spectra and comparison of its NMR data with those of known analogues.

4-Methylenesterols from a sponge Theonella swinhoei.

Three new 4-methylenesterols, theonellasterol K (1), acetyltheonellasterol (2) and acetyldehydroconicasterol (3), along with two known sterols, theonellasterol (4) and theonellasterone (5), were isolated from the sponge Theonella swinhoei. The structures of these compounds were elucidated on the basis of their spectroscopic data and comparison of the NMR data with those of known analogues. Compound 1 exhibited significant cytotoxic activity against HCT-116, K562 and Molt 4 cancer cell lines.