Blueberry extracts were found to inhibit the formation of Fusobacterium nucleatum biofilms by almost 90%, according to findings published in the Journal of Agricultural & Food Chemistry.
Researchers from Université Laval in Quebec City also report that the blueberry polyphenols also reduce the secretion of inflammatory compounds, and blocked specific pro-inflammatory pathways.
“This dual action of lowbush blueberry polyphenols suggests that they may be promising candidates for novel therapeutic agents,” they wrote.
Nutraceuticals for oral health
There are several different avenues for researchers to explore for nutraceuticals to beneficially impact oral health, ranging from reducing dental plaque-related diseases, such as caries, gingivitis and periodontitis, or even reducing bad breath (halitosis).
Much of the research into the oral health benefits of probiotics has focused on Streptococcus mutans, the main bacteria associated with tooth decay. S. mutans binds to teeth via aggregation forming dental plaque. The bacteria then convert sugar to acid, which attacks the enamel of the teeth.
The new study focused on Fusobacterium nucleatum, which plays a role in periodontal disease.
The researchers report that the extract was composed of 16.6% phenolic acids, 12.9% flavonoids (flavonols, anthocyanins, flavan-3-ols), and 2.7% procyanidins. The extract was tested against F. nucleatum using microplate assays and results showed that a solution with blueberry extract at a concentration of 62.5 micrograms per milliliter inhibited the formation of a F. nucleatum by 87.5%.
“The effect of the blueberry extract on biofilm formation by F. nucleatum was visualized by scanning electron microscopy,” they added. “Electron micrographs clearly showed that there was a marked reduction in mature biofilm and that the architecture was disrupted when F. nucleatum was grown in the presence of the blueberry extract.”
The secretion of inflammatory compounds such as IL-1beta, TNF-alpha, and IL-6 was also inhibited by 87%, 80%, and 28%, respectively, by the blueberry extracts when macrophages were stimulated by F. nucleatum.
“Although the colonization of subgingival sites and subsequent biofilm formation by periodontopathogens such as F. nucleatum is the initial step in the pathogenesis of periodontitis, the host immune response, which results in the overproduction of a large variety of inflammatory mediators involved in tissue and bone destruction, is critical,” explained the researchers.
“In the present study, we showed that blueberry polyphenols possess marked iron-chelating activity, which may be another antimicrobial mechanism. Indeed, by chelating iron, which is an essential cofactor for bacterial growth, blueberry polyphenols may compete with bacteria for iron, creating an iron-deficient, bacteriostatic environment.
“Because the ferrous form of iron is responsible for the formation of reactive oxygen species (ROS), this iron-scavenging property may contribute to the antioxidative activity of blueberry polyphenols.”
Source: Journal of Agricultural & Food Chemistry
Volume 63, Number 31, Pages 6999-7008, doi: 10.1021/acs.jafc.5b01525
“Wild Blueberry (Vaccinium angustifolium Ait.) Polyphenols Target Fusobacterium nucleatum and the Host Inflammatory Response: Potential Innovative Molecules for Treating Periodontal Diseases”
Authors: A. Ben Lagha, S. Dudonne, Y. Desjardins, D. Grenier