Pomegranate May Ward Off Prostate Cancer

LOS ANGLELESPomegranate extract, high in ellagitannins, appears to concentrate in the prostate after administration and protect against prostate cancer cell growth in mice, according to recent research reported in the Journal of Agriculture and Food Chemistry (2007; Epub Aug. 28 ahead of print). Researchers from the University of California (UCLA) following up on a previous phase II clinical studywhich showed pomegranate juice doubled PSA (prostate specific antigen) doubling time in prostate cancer patients with rising PSAconducted an animal trial on pomegranate extract in wild-type male mice, including secondary work in mice given human prostate cancer cells.

Working off the theory that ellagitannins (ETs) hydrolyze to release ellagic acid (EA), which is then converted by gut microflora to 3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one (urolithin A, UA) derivatives, researchers sought to further define the metabolism and tissue distribution of ET metabolites. They administered a standardized ET-enriched pomegranate extract (PE) and UA to the mice, and measured metabolite levels in plasma and tissues over a 24-hour period. After administration of PE and UA, ET metabolites were concentrated at higher levels in mouse prostate, colon, and intestinal tissues, compared to other tissues.

Next, they tested PE on prostate cancer growth in severe combined immunodeficient (SCID) mice injected subcutaneously with human prostate cancer cells (LAPC-4). They noted PE significantly inhibited LAPC-4 xenograft growth in SCID mice, compared to controls. Further, they showed EA and several synthesized urolithins inhibited the growth of human prostate cancer cells in vitro.

The researchers concluded the chemopreventive potential of pomegranate ETs and localization of their bioactive metabolites in mouse prostate tissue suggest that pomegranate may play a role in prostate cancer treatment and chemoprevention. They recommended future human tissue bioavailability studies and further clinical studies in men with prostate cancer.