Pomegranate Studied as Preventive Agent Against Prostate Cancer

Division Of Cancer Prevention

In recent years, the pomegranate has been on the cancer biologists’ research menu because of the Middle Eastern fruit’s promise as an antioxidant capable of targeting multiple pathways in the cancer development process. Hasan Mukhtar, Ph.D., director and vice chair of research in Dermatology at the Medical Sciences Center, University of Wisconsin has done some of the earliest studies to isolate the active ingredients in the pomegranate that have been shown to affect a variety of cancer cells in the laboratory.

Earlier work with pomegranate in Dr. Mukhtar’s lab identified six distinct anthocyanins that have some activity when exposed to cancer cell lines. Flavonoids like these give the pomegranate its color and are beginning to gain a reputation as a dietary supplement that may have beneficial effects against various diseases. “We tested all six of the compounds, but one of them – delphinidin – had distinctly more impact on these cancer cell lines than the others,” he reported. Working as a biological response modifier, delphinidin showed the ability to reduce inflammation, protected healthy cells’ DNA, kept blood vessels from growing that might otherwise support tumors, and limited the number of free radicals that are continuously being generated by the body, Dr. Mukhtar noted.

His current work funded by NCI* is focusing on prostate cancer. The active ingredients in pomegranate appear to affect several steps in some of the early stages of the disease. “We’re literally slowing this progression of the cancer by interfering at these earlier carcinogenic stages,” Dr. Mukhtar said. Prostate cancer “grows very slowly, likely for decades, before symptoms appear, typically in men older than 50, and a diagnosis is finally established,” he continued. Because of this long latency period, even a modest delay in disease progression for prostate cancer could have a positive impact at the population level, reducing the number of people who develop clinical disease, he noted.

Dr. Mukhtar and his colleagues are looking at delphinidin’s effect on one transcription factor in particular: NFkB. By controlling this cellular “master switch”, other genes are turned on and off and can thus affect many of the molecular pathways involved in the survival of cells, he explained. “We are using a very controlled extract to look at delphinidin’s impact on NFkB in human prostate cancer cells and also prostate cancer animal models in the lab.”

NCI Program Director Marjorie Perloff, Ph.D., commented, “There is a major need for effective and nontoxic agents capable of preventing prostate cancer. Compounds derived from natural substances, such as the pomegranate, hold much promise for potential development as chemopreventive agents. Dr. Mukhtar’s work in tissue culture and in animals to define what compounds in the fruit might be most actively involved as cancer preventive agents provides critical information that allows us to determine whether or not these compounds are suitable for further development as chemopreventive agents and specifically whether or not clinical trials should be undertaken.”