Evaluating the Antibacterial Activities of Thymus Vulgaris L. Essential Oil against Streptococcus Oralis in Vitro Study
Background: Dental biofilm acting a major factor in the cause of gingivitis and periodontitis. The primary colonizers of dental biofilm are of large magnitude in the sequence steps of biofilm creation. Streptococci make about 60% to 80% of oral bacteria existing in the biofilm which shaped on surfaces of teeth. Chemical anti-biofilm agents were used for dental biofilm control and gingivitis prevention which then prevent periodontitis but it has several side effects which necessitates the need for an anti-biofilm agent that has fewer side effects. Thymus vulgaris L. essential oil has been shown to make bacteriostatic and bactericidal effects toward several dental biofilm bacteria. Nevertheless, the antibacterial effect of it on primary dental biofilm colonizer (Streptococcus oralis) has never been tested which was investigated in this study.
Aim: Evaluating the antibacterial effects of Thymus vulgaris L. essential oil against Streptococcus oralis in vitro.
Materials and Methods: The Streptococcus oralis bacteria were isolated by collection of human supra gingival dental biofilm samples from 10 subjects. Presence of the target microorganisms is confirmed using morphological characteristics, Gram stain, and catalase production test, ability for blood haemolysis, Optochin sensitivity and conventional polymerase chain reaction test. Agar susceptibility test was used to study the sensitivity of Streptococcus oralis to Thymus vulgaris L. essential oil as compared to Chlorhexidine 0.2% as a positive control and 10% Dimethyl sulphoxide as a negative control. The minimal inhibitory concentration was defined by means of two-fold serial microdilution method. The minimum bactericidal concentration was also defined.
Results: The Thymus vulgaris L. essential oil showed higher antibacterial activity against Streptococcus oralis than Chlorhexidine. Bacteria was sensitive to different concentrations of the oil with minimum inhibitory concentration was (0.09%) and the minimum bactericidal concentration was (0.09%) for Streptococcus oralis.
Conclusion: The Thymus vulgaris L. essential oil was effective against Streptococcus oralis with bacteriostatic and bactericidal action, and could be used as a natural active agent to produce oral health care products.
Keywords: Streptococcus oralis,Thymus vulgaris L. Essential oil, Chlorhexidine, Antibacterial