4α-Methylated steroids with cytotoxic activity from the soft coral Litophyton mollis

Seven new (1-3, 5 and 8-10) and three previously reported (4, 6 and 7) 4α-methylated steroids were isolated from the organic extract of the gorgonian Litophyton mollis. The structures and the relative configurations of the isolated natural products were determined on the basis of extensive analyses of their NMR and MS data. Metabolites 1 and 5-8 exhibited cytotoxic activity against K562 human chronic myelogenous leukemia cells with IC50 values below 10 μM, while at the same time displaying low toxicity against healthy PBMCs.