Chocolate Compound Fights Cancer

The study, published in the April 2005 issue of the journal Molecular Cancer Therapeutics, explained how pentameric procyanidin (pentamer), a natural ingredient found in cocoa, neutralizes a number of proteins that seem to work together to trigger a cancer cell into continually dividing. "There are all kinds of chemicals in the food we eat that potentially have effects on cancer cells, and a natural compound in chocolate may be one,” said the lead author, Robert B. Dickson, Ph.D., a researcher and professor of oncology at the Lombardi Comprehensive Cancer Center at Georgetown University (Washington DC, USA). "We need to slowly develop evidence about the selectivity of these compounds to cancer, learn how they work, and sort out any issues of toxicity.”

Similar to many other foods, chocolate is the source of many potential anticancer compounds; however, Dr. Dickson points out that this study, which is part of a series of studies performed at Georgetown University on the chocolate-cancer association, does not mean that individuals who eat chocolate will either treat a current instance of cancer or reduce their risk of cancer. Nevertheless, the study was conducted on breast cancer cell cultures, so the result could possible apply to other cancers as well, according to Dr. Dickson.

Chocolate is made from cacao beans and are rich in natural antioxidants known as flavonoids. These substances may protect cells from damage caused by unstable molecules called free radicals, which are believed to contribute to cancer development as well as heart disease. The flavonoids contributing to the antioxidant benefit in chocolate are the procyanidins, and of the various kinds of procyanidins, pentamers appear to be the strongest, according to a number of other research projects.

The researchers, given this, used a purified preparation of pentamer on a variety of breast cancer cells, and looked at what happed compared to treatment on healthy breast cells. They then used an assortment of tests to identify proteins that were deactivated in the cancer cells. What they found were two well-known tumor-suppressor genes as well as two other proteins know to be involved in regulating the cell cycle (the progression of a cell from a state of being "quiet” into division and growth). They discovered that the breast cancer cells stopped dividing when treated with pentamer and that all four proteins were inactivated. Also, expression of one of the genes was reduced.

Dr. Dickson noted that "the novel aspect here is that a pattern of several regulatory proteins are jointly deactivated, probably greatly enhancing the inhibitory effect compared to targeting any one of the proteins singly. That is also why the compound seems to work on cancer cells, irrespective of whether any of these single genes are mutated, which often happens in cancer cells.”

He added that the scientists do not know why pentamer deactivates these proteins simultaneously, stopping the cell cycle. "We don't know at a fundamental level whether a master switch that triggers cell growth is turned off, or whether the chocolate compound exerts multiple independent effects on diverse cellular processes. That will be the subject of future studies here.”


Related Links:
Lombardi Comprehensive Cancer Center at Georgetown University