Document Type : مقاله‌های پژوهشی

Abstract

Introduction: Astragalus honey has valuable therapeutic effects; however, its antibacterial effect is not well understood. In this study the antimicrobial activity of astragalus honey on three species of Lactobacillus strains involved in the process of tooth decay was evaluated.Materials and methods: The present in vitro study wascarried out to determine the effect of different concentrations of astragalus honey on three Lactobacillus species. Different concentrations of honey (9.3, 18.75, 37.5, 75, 150, 300 and 600 ppm) were prepared by adding sterile water to pure honey (1200 ppm). Antibacterial activity of honey was determined by serial dilutions and the disk diffusion method. Data analysis was performed with SPSS 20, using one-way ANOVA and comparison of means with Tukey test (α=0.0001).Results: Although a honey concentration of 1200 ppm strongly inhibited the growth of all the three Lactobacillus strains, concentrations below 75 ppm were more effective. The minimum inhibitory concentrations (MIC) of honey against L. casei (PTCC 1608), L. rhamnosus (PTCC 1637) and L. plantarum (PTCC 1058) were 75, 100 and 100 ppm, respectively and the minimum bactericidal concentrations (MBC) were 100, 150 and 150 ppm, respectively. Zones of inhibition for 1200 ppm concentration at 24, 48 and 72 hours for L. casei were 10.6, 11.2 and 11.77 mm, respectively, with 10.2, 10.3 and 11.05 mm for L. plantarum and 9.14, 9.90 and 10.2 mm for L. rhamnosus, respectively (p value < 0.0001).Conclusion: Based on the results, astragalus honey can be used as a natural antibiotic; however, further studies are necessary to evaluate the antibacterial activity of honey.Keywords: Antibacterial, Honey, Lactobacillus strains.