Synergistic Effect of Methanolic Extracts of Rosmarinus Officinalis and Eugenia caryophyllata on Biofilm of Oral Pathogenic Bacteria

Introduction: Tooth decay is one of the most essential and costly diseases globally, which is caused by the formation of biofilms by various bacteria. This study aimed to investigate the synergistic antibacterial effect of Rosmarinus officinalis and Eugenia caryophyllataon inhibiting the growth and biofilm obtained of Streptococcus mutans and Streptococcus sanguinis bacteria. Methods: Rosmarinus officinalis and Eugenia caryophyllata were extracted by methanol solvent by maceration method and drying. Antibacterial properties were studied by disc, well diffusion, and biofilm formation measurement. Results: Analysis of the results in disc and well method showed that 100mg/ml concentration of Eugenia caryophyllata had the most potent antibacterial effect among different concentrations and the Streptococcus mutans was more sensitive than Streptococcus sanguinis. Measurements of biofilm formation also showed that only 100mg/ml and 80mg/ml concentrations of Eugenia caryophyllata could inhibit Streptococcus mutans biofilm. None of the extracts were able to inhibit the biofilm from Streptococcus sanguinis. Conclusions: 100mg/ml concentration of Eugenia caryophyllata has a similar or more antibacterial effect than commercial chlorhexidine mouthwash and can be considered for future research to make an herbal mouthwash.