Antimicrobial effects of six Algerian propolis extracts

Summary This study aimed to study the antimicrobial effect of propolis and determine the essential compounds which give it the antimicrobial activity. The antimicrobial effect was investigated for six ethyl acetate extracts of propolis (EAPs) collected from different regions of Algeria on four pathogenic strains (Shigella dysenteriae, Shigella sonnei, Staphylococcus aureus and Escherichia coli) and two benefit strains (Bifidobacterium animalis and Lactobacillus rhamnosus). The results obtained in this study indicated that the different EAPs showed potential inhibitory effects on tested pathogenic strains with variable minimum inhibitory concentration (MIC) values of 0.3 and 9 mg ml−1, while the beneficial bacteria showed resistance against EAPs of propolis. The results demonstrated also that the flavonoid compounds have very low MIC values, while phenolic acid compounds have variables MIC values of 1–10 mg ml−1. These results indicated that propolis contains proven substances with antimicrobial activity and are a prelude to the investigations aimed at empowerment of the bee substance as a potential source of antimicrobial agents with multiple outlets. This study has demonstrated that propolis has good antimicrobial effects against pathogenic strains (but not beneficial bacteria). Polyphenol compounds give this natural product the antimicrobial effects.