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

Document Type : Original Article


1 Department of Biology, Faculty of Agriculture and Food Industry, Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran

2 Department of Microbiology, Faculty of Basic Sciences, Islamic Azad University, Lahijan Branch, Lahijan, Iran

3 Medical Microbiology Research Center, Qazvin University of Medical Sciences, Qazvin, Iran

4 Social Development and Health Promotion Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran

5 Lung Diseases and Allergy Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran



Introduction: 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 Melissa officinalis L. (Lemon balm)and mouthwash Vi-one on Streptococcus mutant and Streptococcus sanguinis.
Methods: 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.
Results: The highest non-growth zones were 21 mm for Streptococcus mutant and 22 mm for Streptococcus sanguinis 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).
Conclusion: The results of this study showed the synergistic antibacterial effects of lemon balmand mouthwash on bacteria. More in vivo researches are needed to confirm and use the above combination.