Maple polyphenols inhibit sortase and drastically reduce Streptococcus mutans biofilms

Dental caries is initiated by the adherence of Streptococcus mutans to tooth surfaces, leading to biofilm (plaque) formation and the production of enamel-eroding acids. Sortase A (SrtA) plays a critical role in this process because it anchors many protein adhesins to the bacterial cell wall, making it a promising target for plaque prevention. Our previous research demonstrated that edible polyphenols from maple extracts-nortrachelogenin-8'-O-β-D-glucopyranoside, lariciresinol, isoscopoletin, and (-)-epicatechin gallate (ECG)-inhibit SrtA in Listeria monocytogenes and act as antibiofilm agents. Using in silico modeling based on the X-ray structure of S. mutans SrtA, we found that maple polyphenols, as well as a related compound, (-)-epigallocatechin gallate (EGCG), bind S. mutans SrtA with favorable free energy values. These polyphenols inhibited sortase activity in vitro and reduced S. mutans attachment to hydroxyapatite discs, which mimic tooth surfaces, as well as to acrylic false teeth. Among the tested compounds, ECG exhibited the strongest antibiofilm activity at a 100 µM concentration, significantly outperforming EGCG. Notably, this effect was independent of the S. mutans strain tested. ECG is not only present in maple extracts but is also abundant in green and black tea. Given their efficacy, safety, and natural abundance, we propose that aqueous maple extracts or ECG alone could serve as a safe, cost-effective strategy for preventing dental caries. This approach may be particularly beneficial for young children, for whom antimicrobial oral hygiene products pose toxicity concerns.IMPORTANCEThis study highlights the potential of natural compounds from maple to combat Streptococcus mutans, the bacteria responsible for tooth decay. We identified sortase inhibition as a key mechanism by which maple-derived polyphenols prevent the formation of biofilms on tooth-like surfaces. One of these compounds, (-)-epicatechin gallate, which is also abundant in tea leaves, emerges as a powerful and safe alternative to traditional plaque-fighting agents. Its natural abundance, affordability, and lack of toxicity make it especially promising for inclusion in oral care products like mouthwashes, offering a safer option for children who often accidentally swallow them.