Effect of a Berry Polyphenolic Fraction on Biofilm Formation, Adherence Properties and Gene Expression of Streptococcus mutans and Its Biocompatibility with Oral Epithelial Cells

Abstract

The ability of Streptococcus mutans to adhere to oral surfaces and form biofilm is a key step in the tooth decay process. The aim of this study was to investigate a berry (wild blueberry, cranberry, and strawberry) polyphenolic fraction, commercialized as Orophenol^®, for its antibacterial, anti-biofilm, and anti-adhesion properties on S. mutans. Moreover, the biocompatibility of the fraction with human oral epithelial cells was assessed. Phenolic acids, flavonoids (flavonols, anthocyanins, flavan-3-ols), and procyanidins made up 10.71%, 19.76%, and 5.29% of the berry polyphenolic fraction, respectively, as determined by chromatography and mass spectrometry. The berry polyphenolic preparation dose-dependently inhibited S. mutans biofilm formation while not reducing bacterial growth. At concentrations ranging from 250 to 1000 µg/mL, the fraction inhibited the adhesion of S. mutans to both saliva-coated hydroxyapatite and saliva-coated nickel-chrome alloy. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that incubating S. mutans with the berry polyphenolic fraction was associated with a reduced expression of luxS gene, which regulates quorum sensing in S. mutans. The berry fraction did not show any significant cytotoxicity in an oral epithelial cell model. In conclusion, Orophenol^®, which is a mixture of polyphenols from wild blueberry, cranberry and strawberry, possesses interesting anti-caries properties while being compatible with oral epithelial cells.

Keywords: S. mutans; anti-adhesion; anti-biofilm; berry polyphenols; epithelial cells; quorum sensing.

Figure 1

Effect of the berry polyphenolic fraction (Orophenol^®) on growth and biofilm formation by S. mutans ATCC 25175 (Panel (A)) and S. mutans ATCC 35668 (Panel (B)). Results are expressed as the means ± SD of triplicate assays. *, significant decrease compared to the control assay in the absence of the berry fraction (p < 0.01).

Figure 2

Effect of the berry polyphenolic fraction (Orophenol^®) on the adherence of S. mutans ATCC 25175 (Panel (A)) and S. mutans ATCC 35668 (Panel (B)) to saliva-coated hydroxyapatite (sHA) and saliva-coated nickel–chrome alloy (sNi–Cr). Results are expressed as the means ± SD of triplicate assays. *, significant decrease compared to the control assay in the absence of the berry fraction (p < 0.01).

Figure 3

Effect of the berry polyphenolic fraction (Orophenol^®) on the mRNA expression of comD, gtfC, and luxS in S. mutans ATCC 25175. The expression was normalized to 16S rRNA. Results are expressed as the means ± SD of triplicate assays. *, significantly different from the control assay in the absence of the berry fraction (p < 0.01).

Figure 4

Effect of the berry polyphenolic fraction (Orophenol^®) on the viability of human oral epithelial cells (B11 cell line) following 2 h (Panel (A)) and 48 h (Panel (B)) treatments. Results are expressed as the means ± SD of triplicate assays.