Berry promising anticancer prospects

From San Diego, at the Experimental Biology 2000 meeting

Twelve years ago, scientists uncovered a mechanism to explain why the folk remedy of eating cranberries fights urinary tract infections. It now appears that the medicinal powers of the pucker-inducing berries might extend to breast cancer as well.

For years, Najla Guthrie and her colleagues at the University of Western Ontario in London have been exploring anticancer prospects of flavonoids, natural antioxidants, isolated from citrus juices (SN: 5/4/96, p. 287). Because deeply pigmented berries also contain dozens of such compounds—several with suspected anticancer activity—Guthrie recently turned to cranberries.

Her team gave 24 female mice a normal diet for 12 weeks. For another two dozen animals, the researchers swapped cranberry juice for drinking water. A third set of mice got food with enough cranberry solids—remains of berries after the juice is removed—to make up 1 percent of the chow. One week into the assigned diet, the researchers injected 1 million human breast tumor cells into a mammary gland of each animal.

The mice, genetically engineered to have a compromised immune system, all developed breast cancer. However, eating a cranberry-laced diet significantly delayed the development of those tumors. Whereas mice on the normal diet gave rise to palpable tumors after about 7 weeks, tumors weren’t detected in juice-supplemented animals until 2 weeks later. Mice eating berry-boosted chow developed tumors 4 weeks after mice eating a normal diet did. Autopsies showed that the cranberry products also cut, by more than half, the number of tumors that spread to the lungs and lymph nodes, Guthrie notes.

The greater effect of the cranberry solids may be due to some compounds that they, but not the juice, contain, Guthrie says. She is now examining whether the activity of the berry solids traces largely to one component or to several, “potentially even acting in synergy,” she says.

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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