Dental caries is an infectious disease that results in tooth decay and cavities if left untreated. It is one of the most common diseases around the world. With funding from USDA's Cooperative State Research, Education, and Extension Service (CSREES), a team of scientists in New York examined a group of compounds, called polyphenols, in grapes that could potentially fight the onset of tooth decay.

Streptococcus mutans, one of the primary microbial agents involved with tooth decay and cavity formation, produces a biofilm that covers the teeth. In creating the biofilm, it creates an acidic environment that breaks down the mineral structure of the tooth, producing points of weakness where the onset of disease can occur.

Hyun Koo and colleagues at the University of Rochester Medical Center (URMC) and the New York State Agricultural Experimental Station at Cornell University focused their analyses on red wine grapes and wine-derived byproducts due to their rich and diverse content of polyphenols and availability of the products for research. Previous studies show that polyphenolic compounds in the extracts of grape, apple, cranberry and cocoa act as a natural biological agent against S. mutans' ability to cause the disease.

Their work examined the chemical composition of polyphenolic compounds obtained from whole grape and pomace, a slightly fermented grape mash consisting primarily of skins and seeds. The phenolic compounds from the different wine grape varieties were tested against S. mutans to determine the most effective disruptive agent.

The scientists determined that all wine grape varieties contained high levels of polyphenolic extracts. The extracts, however, did not kill S. mutans. Instead, the extracts were effective at disrupting the bacteria's ability to form the acidic biofilms that cause dental caries. The phenolic extracts obtained from the pomace were slightly more effective than the whole grape in inhibiting acidic bacterial biofilm production.