Curcumin plus silymarin acts against cancer

A study reported recently in the Journal of Cancer found a synergistic effect for the combination of silymarin (a compound occurring in milk thistle) with curcumin (derived from turmeric) against colorectal cancer cells.

"A single phytochemical at high concentration may exhibit anticancer activity," observed authors Amanda Montgomery and colleagues at Saint Louis University. "By combining two phytochemicals, anticancer activity at much lower doses has been sought."

Using three different human colon cancer cell lines, the researchers evaluated the effects of varying doses of curcumin, silymarin, and curcumin combined with silymarin in comparison with controls. Cell proliferation and apoptosis (programmed cell death) were assessed after administration of the compounds.

A significant difference was found between single compound-treated cells and cells treated with both compounds. Combination treatment inhibited significantly more cell growth compared to silymarin alone at all concentrations evaluated. For curcumin alone, only higher concentrations inhibited cell growth to a similar extent as that of curcumin plus silymarin.

While cells treated with silymarin alone had low levels of apoptosis that did not significantly differ from that of the control cells, the combination of silymarin with curcumin increased apoptosis by a factor of five. Further investigation led to the conclusion that curcumin sensitizes cancer cells to silymarin's effects.

In their discussion, Dr Montgomery and colleagues cite previous research in which curcumin has inhibited proliferation and induced apoptosis of several cancer types. Both curcumin and silymarin have been found to inhibit nuclear factor-kappa beta (NF-kB) activity, which regulates proteins involved in cancer survival. "Future studies will explore the NF-kB and apoptotic pathways to understand synergisticeffects of curcumin and silymarin on colon cancer cells," they conclude.