A class of chemicals in red wine grapes may significantly reduce the ability of bacteria to cause cavities, according to a study published in the Dec. 12 issue of Journal of Agricultural and Food Chemistry.
Researchers from the University of Rochester Medical Center (New York) and the New York State Agricultural Experiment Station at Cornell University (Ithaca) wanted to examine the make-up of polyphenols in red wine grape varieties and their ability to interfere with Streptococcus mutans.
They prepared polyphenolic extracts from the 2005 harvest of red wine grape varieties (pinot noir, cabernet franc, baco noir and noiret) and pomace (fermented seeds and skins cast away after grapes are pressed during the winemaking process) from wineries in the Finger Lakes region of New York state. They prescreened the varieties for their phenolic content and chose grape pomace since it was readily available, contains at least as many polyphenols as whole fruit and is an inexpensive source material. They chose red wine grapes since they contain 40 percent more phenol content than white wine grapes.
Researchers found that all polyphenolic extracts inhibited two bacterial glucosyltransferases (GTFs) secreted by S. mutans by as much as 85 percent. Cabernet franc grape extracts were the most effective GTF inhibitors, with pinot noir grapes a close second at concentrations that might be useful therapeutically. None of the extracts from any variety, however, killed the bacteria outright. Grape polyphenols also were found to cause S. mutans to produce significantly less acid.
"Most foods contain compounds that are both good and bad for dental health, so the message is not ‘drink more wine to fight bacteria,’ " said study coauthor Dr. Hyun Koo, assistant professor of dentistry, Eastman Department of Dentistry and Center for Oral Biology, University of Rochester Medical Center. "We hope to isolate the key compounds within the wine-making waste that render bad bacteria harmless, perhaps in the mouth with a new kind of rinse."
The study was funded by a U.S. Department of Agriculture grant to study the influence of grape polyphenols on oral bacteria.
