Evaluation of the antifungal activity of the Iranian thyme essential oils on the postharvest pathogens of Strawberry fruits
Postharvest diseases cause considerable losses to harvested fruits and vegetables during transportation and storage. The aim of this study was to evaluate the antifungal potential of Thymus danensis and Thymus carmanicus against four postharvest pathogenic fungi (Rhizopus stolonifer, Penicillium digitatum, Aspergillus niger and Botrytis cinerea) which can reduce the shelf life of strawberry fruit. The chemical composition of plant oils was determined by capillary gas chromatography and mass spectrometry. Antifungal assays were carried out in vitro using PDA plates. Antifungal potential was found for 2 analysed essential oils. T. carmanicus oils have chemical compositions characterized by carvacrol (70%), p-cymene (12.4%) and γ-terpinene (2.5%) as the major components while the major constituents of the T. danensis were thymol (64.8%), α-terpinene (11.3%) and p-cymene (7.9%). Thymus sp. oils showed inhibitory effect even at low concentration (300 μl/L) against B. cinerea and R. stolonifer and showed inhibitory effect against A. niger and P. digitatum at 600 μl/L. Both essential oils tested in vivo at the preliminary concentration exhibited inhibitory activityagainst the four pathogens.
Key words: Thymus danensis, Thymus carmanicus, antifungal activity.