Effect of Curcumin and Silymarin in Combination Exerts Synergistic Inhibition of Colon Cancer Cell Proliferation

Abstract

Consumption of a diet rich in phytochemicals is efficacious in inhibiting colon cancer. Curcumin is the major component of the spice turmeric, and silymarin, the bioactive component of milk thistle, is used as a supplement for liver disease. We studied the antiproliferative effect of curcumin alone and silymarin alone or the combination of curcumin and silymarin using the colon cancer cell lines DLD‐1, HCT116 and LoVo. Curcumin inhibited colon cancer cell proliferation in a concentration dependent manner, whereas silymarin showed significant inhibition only at the highest concentration assessed. We found synergistic effects when curcumin was held at a constant concentration (12.5 µM) and the silymarin concentration was varied. Pre‐exposure studies were conducted using DLD‐1 cells with curcumin alone followed by different concentrations of silymarin or silymarin alone followed by different concentrations of curcumin. Results indicated that curcumin sensitized silymarin effect whereas silymarin did not sensitize curcumin effect. The outcome of this research study shows that combinations of phytochemicals could prevent or eliminate colon cancer initiation and/or progression.AM is supported by DeNardo Foundation Fellowship.