In vitro inhibitory and biofilm disruptive activities of ginger oil against Enterococcus faecalis

Abstract

Background: This study investigated the antibacterial effect of ginger (Zingiber officinale) oil against a common resistant root canal pathogen known as Enterococcus faecalis. The aim of the study was to determine the inhibition of E. faecalis growth in culture suspension and ability to inhibit growth of bacteria through disruption of pre-formed monospecies biofilm. Methods: Ginger rhizome oil was prepared in two-fold concentration series from 0.04 to 5.00 mg/mL and mixed with brain heart infusion broth inoculated with E. faecalis in anaerobic condition. Among the antibacterial tests performed were the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations using microdilution assays, and anti-biofilm assay on 3-day old pre-form monospecies biofilm on a 94 well-plate. Ampicillin was used as a positive control. Results: The result showed an in vitro dose-dependent bacteriostatic activity towards E. faecalis in suspension broth (MIC 0.04mg/mL) but no bactericidal activity within the tested concentration range. It was also found that the ginger oil inhibitory activity against E. faecalis was comparably less in anti-biofilm activity than against bacteria cultured in suspension solution. Conclusion: The study suggests that at determined concentrations, ginger oil has the potential to be used as an antibacterial agent in the management of root canal infections particularly where newly formed E. faecalis is involved.