Pomegranate, a rich source of antioxidants, has been linked to improved heart health, but a growing body of science indicates the fruit protect against prostate cancer. Studies have also reported a role in joint health by slowing cartilage loss in arthritis.
It is these antioxidants, and particularly ellagitannin compounds like punicalagins and punicalins, which accounts for about half of the fruit's antioxidant ability, that are reportedly behind the proposed health benefits.
The new study, led by Daneel Ferreira from the University of Mississippi, deepens our understanding of how the constituents of the fruit may boost prostate health.
“Our results indicate a previously unexplored pathway through which pomegranate juice constituents may contribute to prostate cancer chemoprevention,” they write.
Writing in the Journal of Agricultural and Food Chemistry, Ferreira and his co-workers report that pomegranate’s ellagitannin compounds may inhibit the activity of s well as activity of cytochrome P450 1B1, an enzyme known to be highly expressed in various human cancers, but not in normal tissues, and an established target in the prevention of prostate cancer.
“Our study has asserted a previously unknown mechanism of action of pomegranate juice constituents, which could potentially contribute to prostate cancer chemoprevention,” they wrote. “We proved that systemically available metabolites of pomegranate juice are effective inhibitors of CYP1B1 enzyme activity/expression and could lower the incidence of prostate cancer initiation and sustenance.”
The researchers performed an in vitro experiment to test the ability of pomegranate ellagitannins and its microbial metabolites to inhibit CYP1B1.
They found that the microbial metabolite urolithin A showed the greatest activity for inhibiting CYP1B1, with a 2-fold selectivity over another enzyme CYP1A1, which actually has anti-cancer activity. Inhibition of CYP1A1 is therefore not desirable.
“It is also well-known that prostate cancer typically possesses long latency periods and develops in older men; therefore, cancer chemoprevention by dietary supplement-based intervention is a desirable form of chemotherapy,” wrote the researchers. “Pomegranate juice consumption, thus, may be of considerable advantage in prostate cancer chemoprevention, not only in patients with a genetic predisposition toward prostate cancer but also in patients undergoing cancer therapy.”
Over half a million men worldwide are diagnosed with prostate cancer every year, with over 200,000 deaths from the disease. The lowest incidence of the cancer is in Asia and the Far East, in particular India and China.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, ASAP article, doi: 10.1021/jf902716r
“Effects of Pomegranate Chemical Constituents/Intestinal Microbial Metabolites on CYP1B1 in 22Rv1 Prostate Cancer Cells”
Authors: S.G. Kasimsetty, D. Bialonska, M.K. Reddy, C. Thornton, K.L. Willett, D. Ferreira