Chemical Composition and Antibacterial Activity of Essential Oils of Thymus Vulgaris L. on Salmonella spp.
Keywords:
lamiaceae, thyme, Thymus vulgaris, thymol, p-cymene, antibacterial activity, SalmonellaAbstract
Introduction: Essential oils are a complex mixture of compounds with numerous industrial uses. Among the aromatic plants with medicinal value, Thymus vulgaris L. is a perennial subshrub of the family Lamiaceae, used as a flavoring and preservative with antiseptic and antimicrobial activity. Salmonella spp. is a gram-negative enteropathogen that causes salmonellosis, a foodborne disease with a notorious increase in recent years.
Objective: To study the chemical composition and antibacterial activity of essential oils of Thymus vulgaris L on Salmonella enteritidis ATCC 17036 and Salmonella paratyphi A ATCC 9150.
Methods: Two essential oils of Thymus vulgaris L were used: one imported, product of the flowers of Thymus vulgaris and Thymus zygis and another experimental oil obtained from the leaves, flowers and stems of Thymus vulgaris. Presumptive identification of the compounds was performed by gas chromatography coupled to mass spectrometry. For preliminary antimicrobial activity, the agar diffusion method and the broth macrodilution method were used to obtain the minimum inhibitory concentration and the minimum bactericidal concentration.
Results: In the commercial oil, 19 components were fully identified, the major ones were thymol (45.3 %) and p-cymene (30.3 %); while in the experimental one, 33 components were found and 32 (97 %) were fully identified, being p-cymene (43.8 %) the most predominant. The commercial sample exhibited inhibition of Salmonella paratyphi A at 4.625 mg/mL with respect to eEO which required 5.5 mg/mL to inhibit Salmonella enteritidis.
Conclusions: Chemically, differences were observed in the compounds present in the oils studied, which may be related to the part of the plant used to obtain them. Both Salmonella species showed susceptibility at relatively low concentrations with respect to the reported toxic dose, which catalogs the essential oil of Thymus vulgaris as a potential biotherapeutic.
