12 January - 20 June 2016

Plant compounds, curcumin and silymarin found to inhibit colon cancer cells

revious studies have reported a link between diet and colon cancer, the third most common type of cancer. Phytochemicals found in fruits, vegetables and spices have been found in previous studies to have a protective effect. A study published in the Journal of Cancer by Ezekiel et al. has suggested that combining curcumin (a major component of turmeric) and silymarin (a component of milk thistle) can inhibit the spread of colon cancer cells and increase cancer cell death.

Previous studies have reported a link between diet and colon cancer, the third most common type of cancer.  Phytochemicals found in fruits, vegetables and spices have been found in previous studies to have a protective effect.  A study published in the Journal of Cancer by Ezekiel et al. has suggested that combining curcumin (a major component of turmeric) and silymarin (a component of milk thistle) can inhibit the spread of colon cancer cells and increase cancer cell death.

Ezekiel et al. treated human colon cancer cell lines with curcumin alone, silymarin alone or a combination of curcumin and silymarin.  The scientists assessed cell proliferation, the process that results in an increase of the number of cells. 

Ezekiel et al. report that silymarin alone showed a significant inhibition of cell growth but only at higher concentrations.  However, curcumin alone exhibited a marked effect on inhibition of cell growth in a concentration-dependent manner, starting at a concentration of 3.125 µM. 

To investigate whether curcumin and silymarin combined exhibited a greater anti-proliferative effect, Ezekiel et al. used curcumin at 12.5 µM with varying concentrations of silymarin (1.56 - 100 µM). They found that at concentrations of 1.56 and 3.125 there was no difference between the two compounds alone but when combined there was a significant difference between combination treatment and single compound treatment even at a low dose.  Combination compounds inhibited significantly more cell growth than curcumin alone (1.56, 3.125, 6.25 µM).  There was no difference between higher concentrations of curcumin alone and curcumin and silymarin compounds combined (25 -100 µM) as maximum cell death had already occurred.  The scientists report that combination treated cells had marked cell rounding and membrane blebbing of apoptotic cells (during programmed cell death (apoptosis), the cell's cytoskeleton breaks up and causes the membrane to bulge outward).  Ezekiel et al. investigated the synergistic interaction (the effect of the two compounds together). When cells were pre-treated with curcumin followed by silymarin, the scientists observed a high amount of cell death, which indicates that curcumin made the cells more responsive to the silymarin effect.

Ezekiel et al. state that “phytochemicals may offer alternative therapeutic approaches to cancer treatments and avoid toxicity problems and side effects that chemotherapy can cause”.  However, the authors continue by saying that “concentrations of curcumin and silymarin that are too high could be harmful to people” and note further research is needed to investigate how curcumin and silymarin impact the actions of molecules, such as genetic transcription and expression that cause cells to change.  The compounds could then be studied in an animal model, followed by humans. However, the researchers state: “We still have much to learn, and for now, it's so much safer to add a little spice to your diet and get your curcumin from foods that contain turmeric, such as curry, rather than taking high doses of the compound.”

RSSL can determine physiologically active compounds, including flavanols and other polyphenols and other phytochemicals in a range of fruits, vegetables, herbals and dietary supplements.  For more information please contact Customer Services on +44 (0) 118 918 4076 or email enquiries@rssl.com

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