Antimicrobial activity of Origanum heracleoticum L. essential oil from Serbia
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.
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. Among the aromatic plant species from family Lamiaceae (Labiateae), genus Origanum occupies a special position. In Europe and, in general, all over the world, the most commonly found oregano species belong to the botanical genus Origanum. Within this genus, Ietswaart (1) recognised three groups, 10 sections, 38 species, 6 subspecies and 17 hybrids based on morphological criteria (2).
Origanum heracleoticum L. (Origanum vulgare L. ssp. hirtum) is widely distributed in the Mediterranean basin and is used as a spicy herb under the name "Greek oregano". It is generally accepted that Greek oregano is of the highest quality (3). Oregano is of great economic importance but this is not only related to its use as a spice. Chemical analysis of the oregano essential oil (EO) revealed the presence of several ingredients, most of which have important antioxidant, antibacterial and antifungal properties (4, 2, 5, 6). The major antibacterial co ...