A class of chemical compounds found naturally in grapes could be used to help inhibit the growth of the bacteria that cause tooth decay. The compounds may even one day be used as active ingredients in common, over-the-counter mouthwash, the researchers said. The study was published late last year in the Journal of Agricultural and Food Chemistry.
The chemicals found in grapes, known as polyphenols, were studied as part of a growing movement in the medical community to develop treatments for bacterial infections without actually killing them. Not only are many bacteria resistant to some treatments, but treatments for mouth sterilization in particular result in beneficial bacteria being eliminated along with harmful bacteria. In this case, the researchers wanted to see if the chemicals found in grape pomace may help inhibit Streptococcus mutans, the dental pathogen that produces tooth-decaying acid and sugary substances called glucans, which cause plaque. S. mutans is resistant to the mouth's natural antibodies.
The researchers, working in collaboration with the University of Rochester Medical Center and Cornell University, sourced red grape samples from wineries located in the Finger Lakes in upstate New York. The scientists used Pinot Noir from Hosmer Winery in Ovid; Cabernet Franc from Cornell Orchards in Lansing; Baco Noir from Pleasant Valley Winery in Hammondsport; and Noiret from Swedish Hill Winery in Romulus. Baco Noir and Noiret are hybrids.
For the study, the scientists exposed S. mutans samples to extracts from grapes as well as from pomace (material remaining after grapes are pressed). All four samples of the pomace were found to reduce the virulence of S. mutans by 70 percent to 85 percent. When the researchers used the whole grape extract, however, the bacteria's virulence was inhibited only 30 percent to 65 percent. Though it remains unclear why, the pomace was able to prevent the bacteria from producing the enzymes necessary for glucan production.
"We have determined that the polyphenolic extracts prepared from the red-wine pomace are effective in inhibiting virulence traits of S. mutans, even though the extracts do not suppress the growth of this pathogen," said study co-author Olga Padilla-Zakour, associate professor of food processing at Cornell and director of the University's New York State Food Venture Center. The scientists also believe that the pomace may work in a way similar to that which was examined in a study on the compound resveratrol (a compound found naturally in grapes), and its help in blocking the ability of gingivits bacteria to reproduce and flourish in the mouth.
However, fans of Finger Lakes wines are unlikely to see any benefit beyond that of taste. "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 author Hyun Koo, assistant professor of dentistry within the Eastman Department of Dentistry and Center for Oral Biology at the Medical Center at Rochester University. "We hope to isolate the key compounds within the winemaking waste that render bad bacteria harmless, perhaps in the mouth, with a new kind of rinse."
Padilla-Zakour added that rinsing the mouth out with red wine, as opposed to waiting for an FDA-approved wine-based mouthwash, may actually be bad for overall oral health. "Wine has a naturally high content of organic acids, and therefore it cannot be used as a mouth rinse because the acids can demineralize the tooth enamel," she said.