Synergistic antibacterial effects of methanolic extract of Melissa officinalis L. and Mouthwash Vi-one on Streptococcus mutant and Streptococcus sanguinis

Abstract

<strong>Introduction: </strong>The use of chemical and vegetable compounds reduces the microbial plaque of the tooth. The aim of this study was to investigate the synergistic antibacterial effects of methanolic extract of <em>Melissa officinalis</em> L. (<em>Lemon balm)</em>and mouthwash Vi-one on <em>Streptococcus mutant</em> and <em>Streptococcus sanguinis</em>.<br /> <strong>Methods: </strong>Methanolic extract of lemon balm was prepared by Soxhlet method. The concentrations of 250, 125, 62.5, 31.25, 15.26, 7.81, 3.9, 1.95, 0.97 and 0.48 mg/ml of methanol extract and mouthwash prepared and mixed in the same proportion.Agar well diffusion, minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were used to determine the antibacterial effect.<br /> <strong>Results:</strong> The highest non-growth zones were 21 mm for <em>Streptococcus mutant</em> and 22 mm for <em>Streptococcus sanguinis</em> which observed at a concentration of 250 mg/ml. The best value of MIC and the MBC for both bacteria were 7.81 and 62.5 mg/ml, respectively. As the concentration increased, antibacterial activity increased as well (p≤0.05).<br /> <strong>Conclusion:</strong> The results of this study showed the synergistic antibacterial effects of <em>lemon balm</em>and mouthwash on bacteria. More <em>in vivo</em> researches are needed to confirm and use the above combination.