In vitro comparison of anti-bacterial effect of Thymus vulgaris and Thymus daenensis essential oil and their effective ingredients Thymol and Carvacrol on Streptococcus mutans strain

Background and Objective: Dealing with dental caries over time, side effects of chemical mouthwashes and increasing bacterial resistance to them has led researchers to look for herbal sources. Considering the antibacterial features of Thymol and Carvacrol as the key ingredients of T.vulgaris and T.daenensis, respectively, this study aimed toward a comparative assessment of the antibacterial effects of T.vulgaris, T.daenensis, Thymol and Carvacrol on S.mutans strain. Method of Evaluation: This study was experimental. S.mutans strain was received from Iranian Institute of Pasteur. Thymol and Carvacrol were purchased from Sigma-Aldrich Chemical Company. T.vulgaris and T.daenensis essential oils were obtained from the leaves of these plants by the distillation method using the Clevenger apparatus. The antibacterial effect was assessed by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and zone of inhibition (ZOI) by macrodilution with disc diffusion at concentrations 15.3-100% of each four materials at 24, 48 and 72 hours. Data were analyzed using SPSS 22 software. Findings: The MIC and MBC of T.vulgaris and T.daenensis essential oils, Thymol and Carvacrol on S.mutans strain were respectively 6.25-6.25%, 6.25-3.125%, 3.125-3.125% and 3.125-3.125%. The results revealed that ZOI increased significantly with the increasing concentrations and ZOI of Thymol and Carvacrol was higher in comparison to T.vulgaris and T.daenensis. Among these four materials, ZOI indicated a significant difference with time increase from 24 to 72 hours only in T.daenensis. Conclusion: The results of this study indicated that T.daenensis essential oil inhibited S.mutans strain growth in a time and concentration-dependent pattern; whereas, the T.vulgaris essential oil, Thymol and Carvacrol did that in a concentration-dependent and time-independent pattern.

کلیدواژه ها:

Streptococcus mutans ، anti-bacterial ، Thymol ، Carvacrol