A new 9,11-secosterol from the soft coral Sinularia granosa

Chemical investigations on the EtOAc-soluble fractions from the EtOH extract of Formosa soft coral afforded a new 9,11-secosteroid, 8αH-3β,11-dihydroxy-5α,6α-expoxy-24-methylene-9,11-secocholestan-9-one (1), along with one known steroid 3β,11-dihydroxy-5β,6β-expoxy-24-methylene-9,11-secocholestan-9-one (2) from Sinularia granosa. The structure of the new metabolite was elucidated on the basis of extensive spectroscopic analysis and by comparison of their NMR data with the known compounds, including 2. Both 1 and 2 were shown to significantly inhibit the accumulation of the pro-inflammatory inducible nitric oxide synthase protein, and 1 also was found to effectively reduce the level of cyclooxygenase-2 protein, in lipopolysaccharide-stimulated RAW264.7 macrophage cells at 10 μM. Furthermore, cytotoxic activity of 1 and 2 toward a limited panel of cancer cell lines was also discovered.