Chemical composition, weed killer and antifungal activities of Tunisian thyme (<i>Thymus capitatus</i>Hoff. et Link.) essential oils

Abstract

The chemical composition, phytotoxic and antifungal activities of the essential oils isolated by hydrodistillation from the aerial parts of Tunisian thyme were evaluated. In order to find best results, different variables (i.e. provenance and phase of plant development) were considered. The chemical composition analysed by gas chromatography/mass spectrometry (GC/MS) revealed variability among provenances displaying interesting chemotypes and that carvacrol (63–84%), limonene (5–10%), δ-terpinene (0–7%), and β-myrcene (0–7%) were the main components. Antifungal ability of Thymus capitatus essential oils was tested by disc agar diffusion against five phytopathogenic fungi: Fusarium avenaceum, F. culmorum, Microdochium nivale var. nivale, Alternaria sp., and Bipolaris sorokiniana. High antifungal activity was observed for the essential oil isolated at the post-flowering development phase for the Bekalta provenance. There was no difference in the antifungal activities of oils isolated at the flowering phase from the other provenances. Thyme essential oils showed high level of weed-killer activity as well against Sinapis arvensis.