Chemical composition and fungicidal activity of commercial essential oils of Thymus vulgaris L

The antifungal activity of commercial Thymus vulgaris oils on the development of mycelium of the phytopathogenic fungi Fusarium solani (Mart.) Sacc., Rhizoctonia solani Kühn and Colletotrichum lindemuthianum (Sacc. et Magn.) Briosi et Cav. was studied. The gas chromatography data showed that the essential oils were rich in thymol (22-38%) and its biogenetic precursors γ-terpinene and p-cymene. The carvacrol content was relatively low in all the oils tested, ranging between 1% and 2%. The fungicidal activity of the oils was correlated with their thymol content. The principal chemical components of thyme oils were then tested using the same concentrations as in the thyme oils. Only the fungicidal activity of thymol was high and close to that of the oils with the same thymol content. The effects of the thyme oils and thymol on the hyphae cytomorphology of the studied fungi was an increased vacuolization of the cytoplasm and accumulation of lipid bodies, undulations of the plasmalemma, and alterations of the mitochondria and endoplasmic reticulum.