Determination of chemical component of essential oil of Origanum dubium plants grown at different altitudes and antifungal activity against Sclerotinia sclerotiorum.

The aim of this study was to determine effect of altitude on the yields, composition, and antifungal activities of the essential oil isolated from Origanum dubium plant populations collected at four different altitudes. The essential oil yield, the content of four compounds and antifungal activities against Sclerotinia sclerotiorum were found to vary in relation to the different altitudes examined. According to the GC‐MS analysis, carvacrol (46.51%–85.65%), linalool (0.24–48.37), p‐cymene (1.89%–7.89%), and γ‐terpinene (0.28%–6.31%) were determined as major compounds of essential oils of the plants collected from different altitudes. Altitude seems one of the factors that affected the quantity and quality of the essential oil of O. dubium. A significant correlation between the amount of carvacrol, p‐cymene, and antifungal activities was determined. The essential oil of plant having the highest content of carvacrol (85.65%) showed the strongest antifungal activity against S. sclerotiorum at relatively very low concentration used (0.75 µl petri−1). Practical applications: The essential oil yields, the chemical compositions and antifungal activities against Sclerotinia sclerotiorum were found to vary in relation to the altitudes where plants grown. Since the yield, chemical composition, and biological activities was affected, altitude seems to be an important factor that should be considered. To the best of our knowledge, this is the first study reporting antifungal activities of essential oil of Origanum dubium against devastating plant fungal disease agent S. sclerotiorum. [ABSTRACT FROM AUTHOR]