Inhibitory effects of the main compounds of oregano essential oil against some pathogenic fungi

The in vitro activity of essential oil compounds of Origanum heracleoticum L. was testedagainst Verticillium dahliae, Fusarium oxysporum, Phoma tracheiphila, Phytophthoracactorum and Botrytis cinerea by the well diffusion method using four different concentrations(from 1 x 104 to 1 x 10-2 μg·ml-1). Analyses by GC-ITMS of the oil extracted by steamdistillation from dried inflorescences made it possible to identify 19 main compounds. Themajor compounds were thymol (39.10 %) followed by γ-terpinene (21.26 %) and ρ-cymene(11.23 %). Carvacrol and the plain essential oil at their higher concentrations showed aninhibitory effect against all pathogens tested. However, the percentage of inhibition was notalways correlated with the concentration.