Researchers from the University of Michigan report that curcumin, found in turmeric, and piperine, found in black peppers, decreased the number of stem cells while having no effect on normal differentiated cells.
The researchers used doses equivalent to 20 times to potency of what could be consumed through the diet – however, such potencies are possible from dietary supplements, said the researchers. Because the research is in vitro and relatively preliminary, the Michigan-based researchers cautioned against taking adding curcumin or piperine supplements to their diet at this time.
“If we can limit the number of stem cells, we can limit the number of cells with potential to form tumours,” explained lead author Madhuri Kakarala.
The results of the study, said to be the first to suggest these dietary compounds could reduce the risk of cancer by targeting stem cells, are published in Breast Cancer Research and Treatment.
According to the American Cancer Society, almost 195,000 new cases of breast cancer will be diagnosed in the US this year, and over 40,000 will die from the disease.
Furthermore, the researchers found that normal, non-cancerous stem cells were unaffected by the compounds, which appeared to selectively target the cancer stem cells.
“This shows that these compounds are not toxic to normal breast tissue,” said Kakarala says. “Women at high risk of breast cancer right now can choose to take the drugs tamoxifen or raloxifene for prevention, but most women won't take these drugs because there is too much toxicity. The concept that dietary compounds can help is attractive, and curcumin and piperine appear to have very low toxicity.”
Curcumin is a natural pigment that gives the spice turmeric its yellow colour. Recent studies have investigated its potential to lower cholesterol levels, improve cardiovascular health, reduce the risk of Alzheimer's and diabetes as well as cancer-fighting properties.
The black pepper extract market, also known as piperine, is dominated by Sabinsa’s BioPerine ingredient, which has seen 250 per cent growth in two years, said the company recently.
The US market for piperine has the potential to reach about $25m, or 40 tons, estimates Sabinsa, but the company also holds patents and trades in Canada, the European Union and Japan and has a patent pending in India.
The study was supported by the National Institutes of Health, while Sabinsa donated both the curcumin and piperine used in the study.
Source: Breast Cancer Research and Treatment
Published online ahead of print, doi: 10.1007/s10549-009-0612-x
“Targeting breast stem cells with the cancer preventive compounds curcumin and piperine”
Authors: M. Kakarala, D.E. Brenner, H. Korkaya, C. Cheng, K. Tazi, C. Ginestier, S. Liu, G. Dontu, M.S. Wicha