Bioactive sterols and sesquiterpenes from the Red Sea soft coral Sinularia terspilli

The ethanolic extract of the Red Sea soft coral Sinularia terspilli was subjected to several chromatographic techniques resulting in the isolation of compounds 1-8 including (five sterols 1-5 and three sesquiterpenes 6-8). The isolated compounds have been identified by 1D and 2D NMR spectral analysis and by comparison with literature data. Different biological activities for the isolated compounds and some synthetic derivatives have been carried out. Compounds 4 and 5 exhibited strong cytotoxic activity against human leukemia cell lines HL60 and K562 with IC50 values ranging from 2.0 to 25 nM. This is the first reported isolation of these metabolites from this soft coral species.