Inhibitory and preventive effects of *Arnebia euchroma* (Royle) Johnst. root extract on *Streptococcus mutans* and dental caries in rats

BACKGROUND: Dental caries is a prevalent oral disease. Arnebia euchroma (Royle) Johnst. root (AR) extracts have anti-inflammatory, anticancer, and antibacterial properties. This study investigated the antibacterial impact of AR extract on Streptococcus mutans (S. mutans) UA159 and its anti-caries effect in rats. METHODS: Antibacterial activity against S. mutans planktonic cells and biofilms was assessed using bacterial and biofilm sensitivity tests and live–dead staining. Fluorescently tagged bacteria were used to evaluate adhesion to saliva-coated hydroxyapatite (HAP). In vivo anti-caries efficacy and safety were assessed in a rat caries model. RESULTS: AR extract inhibited S. mutans growth and biofilm formation, disrupted and reduced established biofilms, and inhibited bacterial adhesion to saliva-coated HAP. In a rat model, AR extract significantly reduced the incidence and severity of smooth-surface and pit-and-fissure caries while showing excellent biosafety. CONCLUSIONS: AR extract shows strong antibacterial activity against S. mutans and reduces dental caries in rats, suggesting Arnebia euchroma could be utilized for prevention and treatment of dental caries.

Zeyu Wu, Jie Song, Yangyang Zhang, Xiyu Yuan, Jin Zhao