Jan 7, 2010
pomegranate and cancer
Eating pomegranates or drinking pomegranate juice may help prevent and slow the growth of some types of breast cancer. A new study shows a group of phytochemicals called ellagitannins found in abundance in pomegranates inhibited the growth of estrogen-responsive breast cancer in laboratory tests.
The abstract of the study says “Estrogen stimulates the proliferation of breast cancer cells and the growth of estrogen-responsive tumors. The aromatase enzyme, which converts androgen to estrogen, plays a key role in breast carcinogenesis. The pomegranate fruit, a rich source of ellagitannins (ET), has attracted recent attention due to its anticancer and antiatherosclerotic properties. On consumption, pomegranate ETs hydrolyze, releasing ellagic acid, which is then converted to 3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one (“urolithin”) derivatives by gut microflora. The purpose of this study was to investigate the antiaromatase activity and inhibition of testosterone-induced breast cancer cell proliferation by ET-derived compounds isolated from pomegranates. A panel of 10 ET-derived compounds including ellagic acid, gallagic acid, and urolithins A and B (and their acetylated, methylated, and sulfated analogues prepared in our laboratory) were examined for their ability to inhibit aromatase activity and testosterone-induced breast cancer cell proliferation. Using a microsomal aromatase assay, we screened the panel of ET-derived compounds and identified six with antiaromatase activity. Among these, urolithin B (UB) was shown to most effectively inhibit aromatase activity in a live cell assay. Kinetic analysis of UB showed mixed inhibition, suggesting more than one inhibitory mechanism. Proliferation assays also determined that UB significantly inhibited testosterone-induced MCF-7aro cell proliferation. The remaining test compounds also exhibited antiproliferative activity, but to a lesser degree than UB. These studies suggest that pomegranate ET–derived compounds have potential for the prevention of estrogen-responsive breast cancers.”
Researchers say the ellagitannins in pomegranates work by inhibiting aromatase, which is a key enzyme used by the body to make estrogen and plays a key role in breast cancer growth.
“We were surprised by our findings,” Chen says. “We previously found other fruits, such as grapes, to be capable of the inhibition of aromatase. But phytochemicals in pomegranates and in grapes are different.”
Researchers say pomegranates have recently been hailed for their potential anti-cancer and heart healthy benefits thanks to their high antioxidant content. But they say this is the first study to look at their effects on aromatase and breast cancer growth.
In the study, published in Cancer Prevention Research, researchers examined the impact of 10 ellagitannin-derived compounds from pomegranates on aromatase activity and breast cancer cell growth in laboratory tests.
The results showed that of those 10 compounds, urolithin B most significantly inhibited breast cancer cell growth.
Experts say further studies will be needed to determine whether eating or drinking pomegranate-derived products will have the same effect in humans, but these results are promising.
“More research on the individual components and the combination of chemicals is needed to understand the potential risks and benefits of using pomegranate juice or isolated compounds for a health benefit or for cancer prevention,” Powel Brown, MD, PhD, chairman of the clinical cancer prevention department at the University of Texas M.D. Anderson Cancer Center. Brown was not associated with the study.
Until then, researchers say people may consider eating more pomegranates to protect against cancer in the breast and perhaps other tissues and organs.
