Antifungal Activity of Essential Oils from Two Varieties of Sweet Basil (Ocimum basilicum L.)

The aim of this work was an evaluation of the antifungal activity of essential oils from two cultivars of sweet basil (Ocimum basilicum L.): ‘Wala’ and ‘Fine Verde’. The essential oils from dried, ground herbs were extracted with the hydro-distillation method using Deryng apparatus. The composition of the oils was analyzed by gas chromatography. The antifungal activity of the oils was tested against the following strains: Alternaria sp., Aspergillus flavus, Botrytis cinerea, Cladosporium herbarum, Eurotium amstelodami and Eurotium chevalieri. The disc diffusion agar method was applied. Each oil was used in two doses, 10 and 5 μl/disc. A disc (6 mm dia.), soaked with oil, was placed on agar plates, which had been previously inoculated with spores of the different strains. The diameters of fungal growth inhibition zones were measured after 72h of incubation at 25°C and expressed in millimeters. The obtained results showed that the diameter of the mycelium growth inhibition zone significantly depended on the source of oil, the dose of oil, and the species of fungi. The essential oil from the ‘Wala’ variety was more effective against the tested fungi than the oil from ‘Fine Verde’ and the inhibition zones were greater when the dose of the oils was higher. E. chevalieri was the most sensitive to both of the oils and A. flavus was the most resistant. The differences in the antifungal activity of the tested oils were probably the result of their different chemical compositions. In comparison with the ‘Fine Verde’ oil, the oil from ‘Wala’ had more than twice the amount of linalool, more 1,8-cineole, and contained geraniol and methyl chavicol. In the conditions of the experiment both oils showed greater antifungal activity than cycloheximide (actidion) and methyl thiophanate (Topsin M 500 SC) used as controls.