ethanolic extracts of aloe vera and propolis as cavity disinfectants: an in vitro study

Introduction: Though a large number of agents including chlorhexidine have been used for cavity disinfection during restorative procedures, till date none has proved to be "ideal." Thus, there is a need for an alternative cavity disinfectant, which is safe, effective, and economic. Herbal extracts of Aloe vera and propolis have shown the potential to be used as cavity disinfectants but not much is known about them. The aim of this study was to evaluate and compare the antibacterial activity of ethanolic extracts of Aloe vera and propolis against S. mutans and L. acidophilus, along with assessing the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Materials and Methods: The study included three groups: 2% chlorhexidine solution (group I), ethanolic extract of Aloe vera (group II), and ethanolic extract of propolis (group III). An MIC test was carried out using tissue culture microplates and serial dilution technique and later to MBC, an aliquot of each incubated well with concentrations higher than MIC was subcultured on brain heart infusion (BHI) medium. Antibacterial assay was carried out using agar disk diffusion technique and zones of inhibition were determined. One-way analysis of variance (ANOVA) was used for intergroup comparison followed by post hoc Tukey′s test for groupwise comparison. Results: Group II and Group III showed bacteriostatic effect but no bactericidal effect against both S. mutans and L. acidophilus. There was a significant difference in the antibacterial activity against both the tested microorganisms among all the groups, the highest being in group I followed by group II and group III. Conclusions: Ethanolic extracts of Aloe vera and propolis are only bacteriostatic and their antibacterial efficacy is inferior to chlorhexidine against both S. mutans and L. acidophilus.