Thymus Vulgaris Effect on Streptococcus mutans Adhesion to Epithelial Cells

Objectives: To test the effect of pre-incubation of S .mutans or buccal epithelial cells (BEC) with different concentrations of aqueous Thymus vulgaris extract (ATE) on the adhesion of S .mutans to (BEC), and comparing it to that of chlorhexidine digluconate.Methods:. Brain heart infusion broth medium containing sterile fresh 5, 10 and 20 % (w/v) leaf extract of T. vulgaris at pH 7.4 was inoculated with S. mutans at log phase to a concentration of 10000 cells/mL and incubated at 37°C. Growth was measured following the absorbance at 420 nm at different intervals. Adherence was assayed microscopically using a mixture of equal volumes of BEC (1 x 100000 cells/mL) and bacteria (1 x 10000000 cells/mL), The number of bacterial cells adhering to every BEC was counted for about 50 BEC, taken at random calculation.The effect of ATE on the adherence of S. mutans on BEC was studied using bacterial cells incubated in the presence of 0,5,10 and 20%ATE for 1h at 37°C then harvested and washed twice with Hank's balanced salt solution (HBSS). Effect of treating BEC with ATE was done using BEC exposed to different concentrations of ATE (5, 10, 20%). Adhesion was also assayed after rinsing the mouth with ATE (5,10, 20%) and chlorhexidine digluconate. Results:83-98% inhibition of bacterial adhesion to pre-incubated BEC with ATE was obtained compared to 75-89% adhesion inhibition to BEC when bacterial cells were pre-incubated with ATE. There was a significant reduction in the adherence of bacterial cells to BEC(89%) after mouth rinse with 20% ATE compared to 45%adhesion inhibition with chlorhexidine digluconate. Conclusions:The diminished adherence of S.mutans to BEC after exposure to various concentrations of ATE may have clinical relevance.