EFFECT OF LIQUORICE AND Azadirachta indica EXTRACTS ON THE EXPRESSION OF VIRULENCE GENES of Enterococcus faecalis

Background: Enterococcus faecalis is usually the most isolated species from oral infections, such as marginal periodontitis, root canals infection, and periradicular abscesses. A number of irrigants are utilized to clean the root canal system. However, new strategies are depending on the natural products rather than standard bactericidal medications.

Methods: Enterococcus faecalis (ATCC 29,212) were used in all experiments throughout this study, several solvents have been used for the purpose of extraction including standard hexane, chloroform, ethyl acetate, n-butanol, ethyl alcohol, and water which are abbreviated as fraction 1,2,3,4,5 and 6, respectively. The minimum inhibitory concentration (MIC) for antibacterial activity assay of different plant extracts (Glycyrrhiza glabra ‘Liquorice’ and Azadirachta indica ‘neem’) was determined by serial dilution. Finally, the effects of each fraction of plant extracts determined on the expression of virulence genes (ace and gelE) in Enterococcus faecalis.

Results: The result showed that Liquorice and Azadirachta indica extracts decreased the expression of virulence genes (gelE and ace) in Enterococcus faecalis. Fraction 5 (ethyl alcohol fraction) of Liquorice extract suppressed the expression of gelE gene while fraction 1 of Azadirachta indica suppressed expression of ace gene.

Conclusions: The present study aimed to determine new therapeutic strategies by evaluating the effects of Liquorice and Azadirachta indica extracts on the expression of virulence genes in Enterococcus faecalis. More studies are required to investigate the effect of different plant extract on virulence genes of Enterococcus faecalis.