Anti-proliferative action of silibinin on human colon adenomatous cancer HT-29 cells.

BACKGROUND: Silibinin a flavonoid from milk thistle (Silybum marianum) exhibit a variety of pharmacological actions, including anti-proliferative and apoptotic activities against various types of cancers in intact animals and cancer cell lines. In the present study, the effect of silibinin on human colon cancer HT-29 cells was studied. METHOD: Incubations of cells with different silibinin concentrations (0.783-1,600 ug/ml) for 24, 48 or 72 h showed a progressive decline in cell viability. RESULTS: Loss of cell viability was time dependent and optimum inhibition of cell growth (78%) was observed at 72 h. Under inverted microscope, the dead cells were seen as cell aggregates. IC50 (silibinin concentration killing 50% cells) values were 180, 110 and 40 ug/ml at 24, 48 and 72 h respectively. CONCLUSION: These findings re-enforce the anticancer potential of silibinin, as reported earlier for various other cancer cell lines (Ramasamy and Agarwal (2008), Cancer Letters, 269: 352-62).