Antimicrobial Efficacy of <i>Teucrium polium</i> L. Extracts for Dental Caries: Green Extraction Techniques and Bioactive Compounds

Dental caries is a highly prevalent chronic condition globally. In recent years, scientists have turned to natural compounds such as plant extracts as an alternative to address concerns related to biofilm-mediated disease transmission, increasing bacterial resistance, and the adverse impacts of antibiotics. Consequently, this study investigated the antimicrobial properties of ethanolic, hydroethanolic, and aqueous extracts of <i>Teucrium polium</i> L. (<i>T. polium</i>), which belongs to the <i>Lamiaceae</i> family, at different concentrations (0.1, 1, 10, 100, 500, 1000 ppm) against seven bacteria commonly associated with dental decay. The hydroethanolic extract demonstrated the highest efficacy against <i>S. mutans</i> (minimum inhibitory concentration (MIC) = 1.24 mg/mL), while the ethanolic extract exhibited the most potent activity against <i>S. sanguinis</i> (MIC = 1.55 mg/mL). For <i>S. sobrinus</i>, the ethanolic extract was the most effective (MIC = 1.52 mg/mL), whereas the hydromethanolic extract displayed the highest efficacy against <i>S. salivarius</i> (MIC = 1.52 mg/mL). <i>S. aureus</i> was most susceptible to the ethanolic extract (MIC = 1.9 mg/mL), whereas the aqueous extract demonstrated the strongest antimicrobial effect against <i>S. epidermidis</i> (MIC = 2.03 mg/mL). Finally, the ethanolic extract exhibited the maximum efficacy against <i>L. fermentum</i> (MIC = 1.36 mg/mL). Overall, the ethanolic extract demonstrated the highest efficacy against all tested bacteria, followed by the hydroethanolic extract, while the aqueous extract showed comparatively lower effectiveness. Therefore, depending on the specific target bacteria, it is suggested to combine the antibacterial extract of <i>T. polium</i> with the most effective solvent to effectively combat the bacteria responsible for dental decay. The study found that mouthwashes containing ethanolic and hydroethanolic extracts, at a concentration of 2.44 mg/L, effectively inhibited the growth of all oral bacteria contributing to dental caries. Future research should explore <i>T. polium</i> extracts' mechanisms of action against oral pathogens, their practical applications, and their efficacy against conventional treatments, paving the way for innovative dental therapies.