Scientists are reporting identification of two substances in licorice
— used extensively in Chinese traditional medicine — that kill the
major bacteria responsible for tooth decay and gum disease, the leading
causes of tooth loss in children and adults. In a study in ACS' Journal of Natural Products, they say that these substances could have a role in treating and preventing tooth decay and gum disease.
Stefan Gafner and colleagues explain that the dried root of the
licorice plant is a common treatment in Chinese traditional medicine,
especially as a way to enhance the activity of other herbal ingredients
or as a flavoring. Despite the popularity of licorice candy in the U.S.,
licorice root has been replaced in domestic candy with anise oil, which
has a similar flavor. Traditional medical practitioners use dried
licorice root to treat various ailments, such as respiratory and
digestive problems, but few modern scientific studies address whether
licorice really works. (Consumers should check with their health care
provider before taking licorice root because it can have undesirable
effects and interactions with prescription drugs.) To test whether the
sweet root could combat the bacteria that cause gum disease and
cavities, the researchers took a closer look at various substances in
licorice.
They found that two of the licorice compounds, licoricidin and
licorisoflavan A, were the most effective antibacterial substances.
These substances killed two of the major bacteria responsible for dental
cavities and two of the bacteria that promote gum disease. One of the
compounds — licoricidin — also killed a third gum disease bacterium. The
researchers say that these substances could treat or even prevent oral
infections.
