Antifungal activity of Nepeta rtanjensis essential oil

The chemical composition and antifungal activity of the essential oil of an endemic Serbian plant Nepeta rtanjensis Diklić & Milojević was studied. The essential oil was isolated from cultivated plants. Inhibition of mycelia growth of five micromycetes, two Alternaria species originally isolated from N. rtanjensis, Cladosporium cladosporoides, Trichoderma viride and Bipolaris spicifera, were tested using the agar dilution method. The essential oil of N. rtanjensis, the main component of which was 4aα,7α,7αβ-nepetalactone, showed strong antifungal activity against all the tested micromycetes. The minimum inhibitory concentration of N. rtanjensis essential oil ranged from 0.6 to 1.4 μg mL-1. The fungi most sensitive to the tested oil were Alternaria species, while Trichoderma viride was the most resistant