Summary Curcumin (diferuloylmethane), the yellow pigment in turmeric (Curcuma longa), is known to inhibit proliferation of cancer cells by arresting them at various phases of the cell cycle and is known to induce apoptosis in tumor cells. Curcumin-induced apoptosis mainly involves the activation of caspase-3 and mitochondria-mediated pathway in various cancer cells of different tissues of origin. In the present, we investigated the induction of apoptosis from colon cancer colo 205 cells to underscore the need for further understanding of the multiple mechanisms of cell death unleashed by curcumin. We examined cytotoxicity and apoptosis in curcumin treated colon cancer colo 205 cells by using flow cytometry and the results demonstrated that curcumin induced cytotoxicity and apoptosis in these examined cells and that these effects are dose-and time-depedent. We also used DAPI staining to confirm curcumin induced apoptosis. We also used flow cytometry to show curcumin induced reactive oxygen species (ROS) and Ca+2 productions and decreased the levels of mitochondria membrane potential and induced caspase-3 activity. We also used Comet assay to show curcumin induced DNA damage in these examined cells. We also used Western blotting to analyze the levels of Bax, Bcl-2, cytochrome C, p53, and p21 in curcumin treated cells and the results demonstrated that curcumin promoted the expression of Bax, cytochrome C, p53 and p21 but inhibited the expression of Bcl-2. These observations together suggest that curcumin may have a possible therapeutic potential in colon cancer patients.
