Public release date: 21-Aug-2007

BOSTON, Aug. 21, 2007 — Compounds in cranberries may help improve the effectiveness of platinum drugs that are used in chemotherapy to fight ovarian cancer, researchers have found in a laboratory study that will be reported today at the 234th national meeting of the American Chemical Society. The scientists demonstrated in cell culture studies that human ovarian cancer cells resistant to platinum drugs became up to 6 times more sensitized to the drugs after exposure to the cranberry compounds in comparison to cells that were not exposed to the compounds, which were obtained from juice extracts.

Although preliminary, the findings have the potential to save lives and reduce the harmful side effects associated with using high doses of platinum drugs for the treatment of ovarian cancer, the researchers say, adding that human studies are still needed. The new study adds to a growing number of potential health benefits linked to cranberries.

The new study focused on cranberry juice because of past research suggesting that the juice has a wide range of potential health benefits, including the ability to fight urinary tract infections, stomach ulcers, and cancer. Singh and his associates obtained ovarian cancer cells that were relatively resistant to platinum. They treated the cells with various doses of a purified extract of commercially available cranberry drink (containing 27 percent pure juice), exposed the cells to the platinum drug paraplatin and compared them to cells that were not exposed to the extract.

Paraplatin killed 6 times more cancer cells that were pre-treated with juice extract compared to cells that were exposed to the cancer drug alone, the researchers say. The extract also slowed the growth and spread of some cancer cells. The maximum amount of juice extract given to the cells was the human equivalent of about a cup of cranberry juice, according to the researchers.

Singh and colleagues believe that the active compounds in the extract are powerful antioxidants called ‘A-type’ proanthocyanidins that are unique to cranberries and not found in other fruits. The researchers add that they do not understand exactly how the cranberry compounds work. However, based on research by other groups, these compounds appear to bind to and block certain tumor promoter proteins found in the ovarian cancer cells, they say. The result is that the cancer cells become more vulnerable to attack from the platinum drugs, the scientists say, noting that the cranberry compounds are not a cure for cancer.