Chemical composition and anti-fungal activities of three essential oils from Satureja spp. on four post-harvest pathogens of strawberry fruit

Post-harvest diseases cause considerable losses to harvested fruits and vegetables during transportation and storage. The aim of this study was to evaluate the anti-fungal potential of the oils from three Iranian Satureja species (S. hortensis, S. khuzistanica, and S. spicigera) against four post-harvest pathogenic fungi (Rhizopus stolonifer, Penicillium digitatum, Aspergillus niger, and Botrytis cinerea) which can reduce the shelf-life of strawberry fruit. The chemical compositions of the plant oils were determined by capillary gas chromatography and mass spectrometry (GC-MS). Anti-fungal assays were carried out in vitro using potato dextrose agar (PDA) plates. The minimum inhibitory concentrations (MIC) and minimum fungicidal concentration (MFC) of the essential oils were determined and compared with each other. Measurable anti-fungal potential was found for three of the essential oils analysed. Satureja spp. oils showed promising inhibitory effects, even at low concentrations (300 mu l l(-1)), against B. cinerea and R. stolonifer, whereas they had anti-fungal effects against P digitatum at 600 mu l l(-1). The essential oils of S. spicigera and S. khuzistanica showed fungistatic effect against A. niger, with a MIC of 300 mu l l(-1). Although all three essential oils showed fungicidal effects against B. cinerea, R. stolonifer, and P digitatum, no fungicidal effect was observed against A. niger, even at high concentrations. All three essential oils were tested in vivo and exhibited inhibitory activities against all four pathogens. S. khuzistanica oil gave the best results and so may be used to decrease, significantly, the incidence of post-harvest diseases in strawberry fruit.