ANTIMICROBIAL ACTIVITY OF SOME ESSENTIAL OILS

Essential oils of Thymus vulgaris (type borneol), Thymus vulgaris (type linalool), Thymus serpyllum, Eucalyptus smitii, Eucalyptus globulus, Eucalyptus radiata, Eucalyptus polybractea, Eugenia caryophyllus (bud), and Rosa damascena were tested for antimicrobial activity against gram-positive Staphylococcus aureus (ATCC 25923), gram-negative Escherichia coli (ATCC 25922), gram-negative Pseudomonas aeruginosa (ATCC 27853), and yeast Candida albicans (ATCC 14053). Antimicrobial screening was done using a qualitative agar diffusion test. All essential oils possessed some antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans. None of the essential oils was active against Pseudomonas aeruginosa. Grampositive Staphylococcus aureus was more resistant to tested essential oils. The yeast Candida albicans was the more sensitive to essential oils. To determine minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), a quantitative serial dilution of the essential oils of Thymus serpyllum, Eugenia caryophyllus, and Thymus vulgaris (type borneol) were utilized in bioactivity tests against Staphylococcus aureus, Escherichia coli, and Candida albicans. The tested essential oils exhibited inhibitory and bactericidal activities against all tested microorganisms at low concentrations. The effect of essential oil vapor was tested using the essential oil of Thymus serpyllum against Staphylococcus aureus, Escherichia coli and Candida albicans. The vapor of essential oil of Thymus serpyllum inhibited the growth of Candida albicans, but did not affect the growth of Staphylococcus aureus and Escherichia coli.