Blueberry leaf polyphenols suppress biofilm formation and restore oral microbial homeostasis for caries control.

BACKGROUND

Dental caries is a dysbiotic biofilm-induced disease driven by Streptococcus mutans (S. mutans). Blueberry leaf polyphenols (BLP) are plant-derived polyphenols exhibiting antimicrobial properties. However, their effects on S. mutans remain incompletely understood.

METHODS

The composition of BLP was determined by ultrahigh-pressure liquid chromatography-triple quadrupole tandem mass spectrometer (UPLC-MS/MS). The minimum inhibitory concentration (MIC) and acid suppression activity were determined. In addition, the effect on biofilm was investigated by adhesion and aggregation assay, crystal violet assay, glycosyltransferases (GTF) activity, extracellular polysaccharides (EPS) quantification, scanning electron microscope (SEM) images and qRT-PCR. Furthermore, we carried out a rat caries model, and microbiome analyzes were performed by 16S rRNA sequencing.

RESULTS

UPLC-MS/MS analysis identified a range of compounds in BLP, including quercetin and chlorogenic acid. The MIC of BLP was 500 μg/mL, and it inhibited the acid production of S. mutans. Importantly, BLP decreased the sucrose-dependent adhesion and its auto-aggregation, inhibited the activity of GTF, resulting in reduced EPS and down-regulated genes like gtfB, comA and gbpB. In addition, it inhibited dental caries in rats and ameliorated the microbiota dysbiosis associated with caries.

CONCLUSIONS

BLP combats caries by inhibiting S. mutans growth, biofilm formation and restoring the oral microbiota.