Chemical composition and inhibitory activity of selected essential oils against fungi isolated from medicinal plants

Abstract

In recent years great attention was paid to biological control, the application of natural products in order to protect crops and medicinal plants against contamination with phytopathogenic and saprophytic fungi. Essential oils have been evaluated as a potentially safe replacement for chemicals used for that purpose. In this regard, antifungal potential of six essential oils was examined coupled with determination of the complete qualitative and quantitative chemical composition by GC-FID and GC-MS analysis. While essential oils of rosemary, sage, Spanish sage and black pepper were exclusively composed of monoterpenes, vetiver essential oil was entirely composed of sesquiterpenes. In essential oil of cinnamon dominates (E)-cinnamaldehyde. Applying the in vitro microdilution method, it was found that all essential oils were active in inhibiting the growth of all tested 21 pre- and post-harvest phytopathogenic and saprophytic fungi. MIC and MFC ranged from 1.2 mg ml-1 up to 22.6 mg ml-1 according to the test oil. Rosemary oil showed the best antifungal potential, followed by black pepper and cinnamon oil. Sage and Spanish sage oils also exhibited significant antifungal potential. Vetiver oil demonstrated the lowest antifungal activity. Essential oils that showed considerable antifungal potential are good candidates for further examination of their use in preventing and/or protection of medicinal plants, their seeds and dried drugs against fungal infections, both in the field and in warehouses.