Result indicated that the number of fractions in the Propolis samples extracts were 33 with different percentages. The HPLC analysis indicated the presence of phenolic compound, cinnamic acid and its derivatives, flavonoids and esters. Result obtained indicated variable differences in percentages of the compounds in samples collected from four countries. Propolis extract antimicrobial activity aginst pathogenic bacteria was investigated in vitro.Minimal inhibitory concentration (MIC) for the strains tested was determined using the method of broth dilution with the propolis extract in serial concentrations.Results of MIC showed MRSA with(0.5-10) followed by Bacillus subtilis with (0.5-15) and Micrococcus with (4-10). The MIC of Gram-negative bacteria showed Proteus vulgaris with(5-15) followed by , Pseudomonas aeruginosa with (10-21) and , Escherichia coli with (15-21).Futhermore the results obtained indiacted that Iranian propolis was the most potent inhibitor for all types of tested bacteria. The results exhibited that propolis is more efficient than some antibiotic discs .
Key Words : propolis , pathogenic bacteria , chemical composition , antimicrobial activity .