Rattiporn Kaypetchรัตติพร กายเพชรThaniya Muadcheingkaธนิยา หมวดเชียงคะPairin TonputMahidol University. Faculty of Dentistry. Research OfficeMahidol University. Faculty of Dentistry. Department of Oral Microbiology2016-02-092016-12-132016-02-092016-12-132016-02-022015-09Kaypetch R, Muadcheingka T, Tonput P. Antibacterial activity of Ocimum sanctum oil against Streptococcus mutans: in vitro. M Dent J 2015; 35: 311-9.0125-5614 (printed)https://repository.li.mahidol.ac.th/handle/123456789/1005Objectives: This study aimed to investigate the antibacterial effect of essential oil extracted from Ocimum sanctum against caries-related bacteria, Streptococcus mutans. Materials and methods: Essential oil extracted from leaves of Ocimum sanctum by steam distillation (Botanicessence, Bangkok, Thailand) were used in this study. The antibacterial effect was determined against Streptococcus mutans ATCC 25175 and Streptococcus mutans KPSK2 using disc diffusion and micro broth dilution technique. Results: Ocimum sanctum essential oil had antibacterial effects against both strains of Streptococcus mutans with the zone of inhibition ranging from 7 to 25.95 mm. The antibacterial effect against Streptococcus mutans KPSK2 was more potent than that on Streptococcus mutans ATCC 25175. Minimum inhibitory concentration of Streptococcus mutans ATCC 25175 and Streptococcus mutans KPSK2 equal to 0.188 and 0.047 mg/ml, respectively. Minimum bactericidal concentration against Streptococcus mutans ATCC 25175 and Streptococcus mutans KPSK2 equal to 0.377 and 0.095 mg/ml. Conclusion: Essential oils from Ocimum sanctum showed moderate antibacterial effect against both strains of Streptococcus mutans. It can be beneficial to use as an agent to prevent or aid the treatment of dental caries.engMahidol UniversityAntibacterial activityCaries-related bacteriaDisc diffusion techniqueEssential oilOcimum sanctumStreptococcus mutansOpen Access articleวิทยาสารทันตแพทยศาสตร์มหิดลMahidol Dental JournalArticleMahidol University