3-Oxo-cinobufagin

3-Oxo-cinobufagin (compound 8), a potential anticancer agent, is extracted from M. spinosus broth using high performance liquid chromatography. This compound is unique among its isolated counterparts because its C-5 hydroxyl group is further oxidized or isomerized, which significantly reduces its cytotoxic activity against most cell lines, except for HEL. However, it demonstrates increased activity in BEL cell strains. The IC50 values of 3-Oxo-cinobufagin for cytotoxicity against cancer cells are: 71.3 μM (HepG2), 90.2 μM (SMMC-7221), 0.11 μM (BEL-7402), 72.5 μM (K562), 5.3 μM (HL-60), and 12 nM (HEL) .