Essential oil chemical composition and antifungal effects on Sclerotium cepivorum of Thymus capitatus wild populations from Calabria, southern Italy

Abstract

The paper reports the qualitative and quantitative composition and its antifungal activities of Thymus capitatus (L.) Hoffmanns. & Link, Lamiaceae, essential oils isolated by hydrodistillation from the aerial parts of plants collected in Calabria, Southern Italy. The essential oils of 22 samples were analysed by GC-Flame ionization detection and GC/MS. A total of sixty five compounds were identified. Phenols were present in highest percentage (average: 79,03%). Carvacrol was the main component (81,52%-78,40%) in all samples, confirming that T. capitatus is a carvacrol chemotype, according to literature data for this species. This essential oil was also characterized by high level of biogenetic precursor of the phenols: p-cimene (4,98%), γ-terpinene (3,13%) and by β-cariophyllene, were the most abundant sesquiterpene hydrocarbons. Antifungal activity against Sclerotium cepivorum Berk., a soil born fungus, was tested. At the concentration of 250 ppm there was no development of fungal mycelium. To our knowledge, studies have never been conducted on Calabria wild populations of T. capitatus essential oil nor were conducted studies on parasitic fungi of specific interest for crops such as Sclerotium cepivorum.