Objective: The aim of this in vitro study was to evaluate the antibacterial activity of trans-trans-farnesol (tt-farnesol) and 1-lauroyl-rac-glycerol (lauroyl) on A. actinomycetemcomitans and their toxicity on oral fibroblasts.
Method: A. actinomycetemcomitans smooth strain (D7S-1) at 106 cells/ml was cultured in TSBYE medium at 37oC in 5% CO2 (n=9). The minimum inhibitory concentration (MIC) was determined by exposing the bacterial cells to serial dilutions of tt-farnesol/ 1% DMSO (range of 0.2µM – 2mM) and 1-Lauroyl-rac-glycerol/water (range 0.2µM – 2mM). Gentamicin 1mg/mL was used as a positive control and 1% DMSO was used as a vehicle control. To evaluate the inhibitory effect of those compounds, the bacterial growth was estimated after 24h. The toxicity of those compounds was performed with oral fibroblasts (ATCC: CRL-7421) at 105 cells/ml (n=9), incubated overnight in DMEM/10%FBS at 37oC in 5% CO2.The viability of cells was observed by fluorometric method (Resazurin). In addition, the morphological characteristics of fibroblasts were observed under the microscope.
Result: The MIC of tt-farnesol and lauroyl was 200µM. In oral fibroblasts culture, the toxicity of tt-farnesol was 2mM and lauroyl did not show any cytotoxic activity in highest concentration tested. The therapeutic index of tt-farnesol was 10, and lauroyl was >10.
Conclusion: This study shows that tt-farnesol and lauroyl had inhibitory effects on A.actinomycetemcomitans growth and the therapeutic indexes show that these compounds have potential to be used as an antibacterial agent in oral diseases.