March 10, 2009

Cranberry chemicals prevent infections

Chemicals present in cranberries prevent infection-causing bacteria from attaching to the cells that line the urinary tract, U.S. researchers said.

Paola Pinzon-Arango, Yatao Liu and Terri Camesano of Worcester Polytechnic Institute in Massachusetts, exposed E. coli grown in culture to either light cranberry juice cocktail or cranberry proanthocyanidins -- chemicals found in cranberry products -- and measured the adhesion forces between the bacteria and a silicon surface using atomic force microscopy.

The study demonstrated that the longer the bacteria were exposed to either the cranberry juice or the proanthocyanidins the greater the decrease in bacterial attachment.

The study authors noted the effect was reversible -- bacteria grew again in an environment without cranberry juice or proanthocyanidins regaining the ability to attach to the model surface.

Cranberries, one of only three species of fruits native to North America, has a long history of medicinal food use. Native Americans used the fruit for the treatment of bladder and kidney ailments hundreds of years ago, said Dr. Sheldon S. Hendler, co-editor in chief of the Journal of Medicinal Food, and of the University of California, San Diego, said in a statement.