Wild Blueberry (Vaccinium angustifolium Ait.) Polyphenols Target Fusobacterium nucleatum and the Host Inflammatory Response: Potential Innovative Molecules for Treating Periodontal Diseases

Blueberries contain significant amounts of flavonoids to which a number of beneficial health effects in humans have been associated. The present study investigated the effect of a polyphenol-rich lowbush blueberry (Vaccinium angustifolium Ait.) extract on the two main etiologic components of periodontitis, a multifactorial disorder affecting the supporting structures of the teeth. Phenolic acids, flavonoids (flavonols, anthocyanins, flavan-3-ols), and procyanidins made up 16.6, 12.9, and 2.7% of the blueberry extract, respectively. The blueberry extract showed antibacterial activity (MIC = 1 mg/mL) against the periodontopathogenic bacterium Fusobacterium nucleatum. This property may result from the ability of blueberry polyphenols to chelate iron. Moreover, the blueberry extract at 62.5 mu g/mL inhibited F. nucleatum biofilm formation by 87.5 +/- 2.3%. Subsequently, the ability of the blueberry extract to inhibit the NF-kappa B signaling pathway in U937-3x kappa B cells was investigated. The blueberry extract dose-dependently inhibited the activation of NF-kappa B induced by F. nucleatum. In addition, a pretreatment of macrophages with the blueberry extract (62.5 mu g/mL) inhibited the secretion of IL-1 beta, TNF-alpha, and IL-6 by 87.3 +/- 1.3, 80.7 +/- 5.6, and 28.2 +/- 9.3%, respectively, following a stimulation with F. nucleatum. Similarly, the secretion of MMP-8 and MMP-9 was also dose-dependently inhibited. This dual antibacterial and anti-inflammatory action of lowbush blueberry polyphenols suggests that they may be promising candidates for novel therapeutic agents.