The Antimicrobial Properties of Malaysian Propolis as Intracanal Medicament in Endodontics

Numerous studies have shown that propolis, from the sting and stingless bees, possessed antimicrobial, antifungal, antidiabetic, antitumoral and antioxidant properties. Propolis produced by stingless bees, Heterotrigona itama, also possessed these properties but in varying intensity. Exploiting this natural product with antimicrobial properties against Enterococcus faecalis (EF), would be advantageous in endodontics. Particularly where the current synthetic medicament, calcium hydroxide (Ca(OH)2), failed to remove these bacteria, predominantly found in failed root canal-treated (RCT) teeth. The aims of this study are to determine the antimicrobial properties of Malaysian propolis (MP) against Enterococcus faecalis and to compare the antibacterial effect of MP with Ca(OH)2 as an intra-canal medicament. Raw propolis was purchased from Humaira Honey Sdn Bhd, Lenggong, Perak and the ethanolic extraction method was carried out until lyophilization. Antimicrobial susceptibility testing (AST) was done on five samples, namely, MP, Ca(OH)2, 2% chlorhexidine (CHX), 70% ethanol, and sterile normal saline (SDW), where CHX, 70% ethanol and SDW as controls. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) methods were carried out. The MIC and MBC for MP and CHX were done using the micro-dilution method on 96-well, while Ca(OH)2 were performed using the serial macro-dilution method. The results were analysed by Kruskal Wallis test with Mann-Whitney posthoc test and repeated-measures ANOVA with Bonferroni post hoc test (p <0.05). The mean MIC from three trials that were carried out on the samples was CHX (<0.008%) < MP (0.03%) < Ca(OH)2 (0.62%). While the MBC values for three trials were found to be CHX (0.011%) < MP (0.07%) < Ca(OH)2 (1.25%). In conclusion, MP was shown to be antibacterial and effective against Enterococcus faecalis and is more effective when compared to Ca(OH)2, which is commonly used as an intra-canal medicament. Further research is needed to test MP’s clinical efficacy.