Comparative evaluation of antimicrobial efficacy of Syzygium aromaticum,Ocimum sanctum and Cinnamomum zeylanicum plant extracts against Enterococcus faecalis: a preliminary study

Abstract

To evaluate the antimicrobial efficacy of Ocimum sanctum, Cinnamomum zeylanicum, Syzygium aromaticum and 3% sodium hypochlorite (NaOCl) against Enterococcus faecalis in planktonic suspension and biofilm phenotypes. The antibacterial efficacy of different concentrations of aqueous ethanolic extracts of O.sanctum, C.zeylanicum and S.aromaticum against E.faecalis at various time intervals was assessed using the agar well diffusion test, microdilution test and biofilm susceptibility assay (BSA) on cellulose nitrate membrane as well as in a tooth model. NaOCl was used as the positive control. Distilled water was used as negative control for agar diffusion and microdilution tests and phosphate-buffered saline for the BSA. The results of the agar diffusion test were analysed statistically using anova and Tukey's tests. Cinnamomum zeylanicum, S.aromaticum and O.sanctum exhibited minimum bactericidal concentration at 10%, 10% and 40%, respectively. Cinnamomum zeylanicum, S.aromaticum, O.sanctum and NaOCl showed complete bacterial inhibition in planktonic form after exposure of 30, 15, 35 and 1min, respectively. In BSA on cellulose nitrate membrane, NaOCl was associated with complete bacterial inhibition after contact of 2min, whilst 10% C.zeylanicum, 10% S.aromaticum and 40% O.sanctum showed cessation of growth after 12, 12 and 24h, respectively. The results of BSA on tooth model were similar except for O.sanctum, which was not included in the model. Cinnamomum zeylanicum, S.aromaticum and O.sanctum demonstrated antimicrobial activity against planktonic and biofilm forms of E.faecalis with C.zeylanicum and S.aromaticum having better antimicrobial efficacy than O.sanctum. NaOCl had superior antimicrobial efficacy amongst all the groups.