Antimicrobial activity of Origanum heracleoticum L. essential oil from Serbia

Abstract

The modern trends in nutrition suggest the limitation of synthetic food additives or the substitution with natural ones. Aromatic herbs are probably the most important source of natural antimicrobial agents. The aim of this study was to investigate antibacterial effects of various concentrations of Origanum heracleoticum essential oil on the food-borne bacteria. The antimicrobial activity of Origanum heracleoticum essential oil was evaluated using laboratory control strains Escherichia coli ATCC/10536/, Salmonella choleraesuis ATCC/10708/, Salmonella enteritidis ATCC/13076/, Proteus mirabilis ATCC/12453/, Pseudomonas aeruginosa ATCC/10145/, Staphylococcus aureus ATCC/11632/, Bacillus cereus ATCC/10876/and Enterococcus faecalis ATCC/14506/, obtained from the American Type Culture Collection. The antimicrobial activity was determined using disk diffusion method and more precise broth microdilution method. Using the broth microdilution method essential oil of Origanum heracleoticum L. showed antimicrobial activity against all tested strains of microorganisms with exception of the test strain of Pseudomonas aeruginosa. The tested oil had antibacterial effect on gram-positive bacteria in the range of MIC/MBC=0.2-0.39/0.78 μl/ml. The essential oil was active in the range from MIC/MBC=0.39 to 50/0.78 to 50 μl/ml against the tested gram-negative bacteria. P. aeruginosa ATCC/10145/showed the lowest sensitivity of MIC/MBC=50/50 μl/ml.