Berry Compound Thwarts Enzyme Linked to Cancer

Recent research by Agricultural Research Service (ARS) scientists and cooperators has fortified the standing of pterostilbene, a berry and grape compound cited for its health benefits, as a cancer inhibitor.

During tests employing cell fragments from mice livers, ARS chemist Agnes Rimando and colleagues in Poland found that the compound strongly suppresses a type of an enzyme that activates cancer-causing processes.

Rimando, who works at the ARS Natural Products Utilization Research Laboratory in Oxford, Miss., and her collaborators targeted an enzyme called cytochrome P450, which sets off a variety of compounds—known as “procarcinogens—that can turn substances such as cigarette smoke and pesticides into cancer-causing agents. Cytochromes are a factor in people’s varying responses to drugs and toxins entering their bodies.

Rimando has led numerous animal studies that focused on pterostilbene (pronounced "tare-o-STILL-bean") and its potential benefits to human health. This includes work showing that pterostilbene can help lower cholesterol and prevent heart disease, and that the compound is present in a genus of shrubs that includes many types of berries, including blueberries.

She also led studies that found that the compound is a powerful antioxidant that shows cancer-fighting properties similar to those of resveratrol. Indeed, pterostilbene is a derivative of resveratrol, a compound found in large quantities in the skins of red grapes that's known for its cardiovascular and cancer-fighting benefits.

In the most recent study, Rimando and scientists led by Renata Mikstacka at Poland's University of Medical Science in Poznañ tested pterostilbene and other resveratrol derivatives.

Pterostilbene showed strong inhibitory activity—much more than resveratrol—against a particular form of cytochrome P450, according to Rimando. She added that the results may explain the cancer-preventive property the compound demonstrated in a mouse mammary gland culture assay.

However, Rimando cautioned that more studies are needed to explain this process, as well as the activity of other trans-resveratrol compounds.

Read more about this research in the November/December 2006 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.