Background: Dental caries still remain a highly prevalent disease among all age groups especially children. It is caused
due to repetitive and/or prolonged demineralization of tooth enamel caused by exposure to low pH from organic acids
produced by acidogenic oral bacteria during fermentation of dietary carbohydrates. Streptococcus mutans is a facultative
anaerobic , gram positive cocci commonly found in the human oral cavity which plays an important role in causing dental
caries. Moringa oleifera Lam. (drumstick tree) is a Moringaceae family member which possesses a variety of advantageous
biological properties, such as immunomodulatory, anticancer, antiulcer and antimicrobial properties. Thymus vulgaris is
a pleasant smelling perennial shrub which has a direct influence on many bacteria species. The use of combinations of
these two EOs and their components are thus a new approach to increase the antimicrobial efficacy of EOs , taking
advantage of their synergistic and additive effects.
Materials and methods: The broth microdilution method was used to determine the minimum inhibitory concentration(MIC)
of the essential oils. The MIC of Moringa, Thyme and combination of the both essential oils against S.mutans which were
used in the assay were assessed at a different concentration level.
Results: The antimicrobial activity of M.oleifera, T.vulgaris and combination of both the essential oils was proven with the
MIC value of 2.5%v/v, 0.03906% and 0.03906% respectively.
Conclusion: The combination of Moringa oleifera and Thymus vulgaris essential oil can be used as a good antimicrobial
agent to treat various Streptococci borne oral infections. Further incorporation of this oil into the drug formulations is
also recommended to treat S.mutans borne oral as well as systemic infections.
Key words: Streptococcus mutans, Moringa oleifera, Thymus vulgaris, essential oils, antimicrobial activity, synergistic effect.