Bactericidal Activity of Brazilian Red Propolis on Common Oral Pathogens

Objectives: The aim of this study was to evaluate the bactericidal activity of Brazilian Red Propolis (BRP) on common oral pathogens. BRP is a natural, complex, resinous mixture produced by Apis mellifera bees, for utilization in the assembly and repair of hives.
Methods: For this study, the bactericidal activity of raw BRP was evaluated for the following pathogens: Streptococcus mutans, Streptococcus sobrinus, and Streptococcus intermedius. Raw BRP was dissolved in 80% ethanol and antimicrobial activity was qualitatively assessed using an agar diffusion assay. This assay was designed to eliminate the intrinsic antimicrobial properties of the ethanol diluent and assess only the antimicrobial properties of BRP. BRP showed growth inhibition activity against S. mutans, S. sobrinus, and S. intermedius using this assay. Furthermore, the bactericidal activity of BRP in liquid was evaluated against same oral pathogens over time. Data was subjected to statistical analysis and t-test with a pre-set alpha of 0.05.
Results: When compared to ethanol control (3.2%), raw BRP resulted in increased bactericidal activity at a concentration of 100µg/mL for all pathogens evaluated, for any exposure time. At 60min, the bactericidal activity for both 10ug/mL and 100ug/mL concentrations were significantly higher against S. intermedius when compared to their respective ethanol concentrations at exposure time. The concentration of 100ug/ml was completely bactericidal, while 10ug/mL would kill 95.01% +/- 3.66%.
Conclusions: Our results corroborate previous studies data and suggest that the use of a natural product, such as BRP, could result in antimicrobial activity for common oral pathogens, including the endodontic pathogen, S. intermedius. Studies are being conducted in order to determine bactericidal activity against other endodontic pathogens including, Prevotella intermedia, Fusobacterium nucleatum, and Parvimonas micra.