Antibacterial Activity of Synthesized ZnO Nanoparticles in Combination with Zataria multiflora Essential Oil against Oral Cavity Streptococcus mutans

The use of various nanoparticles and plant-based antibacterial substances can be a suitable alternative to conventional mouthwashes. The aim of this study was to investigate the antimicrobial effect of synthesized ZnO nanoparticles in combination with Zataria multiflora essential oil against Streptococcus mutans. ZnO-NPs were synthesized by zinc acetate and potassium hydroxide and their characteristics are evaluated by FE-SEM and XRD. Z. multiflora essential oil is extracted and its chemical compounds are analyzed by GC–MS. Antibacterial activity of essential oil and nanoparticles was studied by broth microdilution method against standard and clinical strains of S. mutans and was determined minimum inhibitory concentration (MIC). The antibacterial interactions of these materials are tested by checkerboard titration. The results showed that ZnO-NPs were spherical and were synthesized with an average diameter of 23.77nm. MIC of ZnO-NPs against S. mutans strains was reported in the range of 12.5-50 μg/ml, and the MIC of Z. multiflora essential oil was in the range of 0.031-0.25 μl/ml. It was observed that ZnO nanoparticles with essential oil of Z. multiflora have synergistic effects against S. mutans and can be a suitable alternative to mouthwashes such as chlorhexidine.