Purpose: To evaluate the antimicrobial effect of Egyptian propolis vs New Zealand propolis on Streptococcus mutans and lactobacilli in saliva.
Materials and Methods: The strains used for the experiment were isolated from 12 patients having a high caries index. The ethanolic extract (EEP) of pure Egyptian propolis was obtained by dissolving 20 g of propolis in 70% aqueous ethanol to a final volume of 100 ml. The commercial New Zealand propolis, combined with antibacterial agents, was an ethanolic extract of propolis in lozenge form; this was dissolved in distilled water to obtain an EEP. The EEP was further fractioned using a liquid-liquid extraction technique with hexane and chloroform solvents. The antimicrobial properties of the two propolis types and their fractions on Streptococcus mutans and lactobacilli were examined separately by determining minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Twelve clinical isolates were obtained from the collected saliva of all patients, one (Streptococcus mutans and Lactobacilli) from each patient, for susceptibility testing.
Results: The MIC values of the New Zealand propolis were lower than the MIC values of the Egyptian propolis, indicating that the New Zealand propolis and hexane fractions (H-fr) in general had stronger antimicrobial effects. In addition, its antimicrobial action was greater on S. mutans than on lactobacilli, except with H-fr they were the same.
Conclusion: The commercial New Zealand propolis hexane fraction had the strongest antimicrobial action. The EEP had a more potent antimicrobial effect on S. mutans than on lactobacilli.
Keywords: bactericidal effect, lactobacilli, propolis, Streptococcus mutans