Hosien Hashemi Moghaddam - Department of Horticultural Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran
Fatemeh Sefidkon - Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
Ali Ashraf Jafari - Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
Sepideh Kalate Jari - Department of Horticultural Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran

Nepeta binaludensis Jamzad is an endemic and rare perennial plant belonging to the Lamiaceae family which grows in a limited area in Binaloud Mountain in northeast of Iran. In order to study the effect of drying methods on its essential oil content and composition, the aerial parts were collected in flowering stage from its habitat at altitude of ۲۶۵۰ m above sea level in July ۲۰۱۸. Seven drying methods as sun drying, shade drying, oven drying at ۳۰oC, ۴۰oC and ۵۰oC and microwave drying (۱۸۰W and ۳۶۰W) were applied in three replications. The essential oils of all samples were obtained using a Clevenger type apparatus during ۳ h. The essential oils were analyzed using gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS). Data statistically analyzed using one way ANOVA (CRD) with three replications and mean comparison were made using the Tukey method. The highest oil yield was obtained in oven drying ۵۰ °C (۲.۱۶%) followed by shade drying (۱.۹۶%). In contrast, the lowest values of essential oil content, ۱.۰۹ and ۰.۶۵%, were obtained in sun drying and microwave ۳۶۰W, respectively. Twenty-four compounds were identified in the essential oils of N. binaludensis with various drying methods with neptalactone (۲۳.۱-۵۴.۰%), ۱,۸-cineol (۲۵.۵-۵۱.۰%) and myrcene (۲.۰-۴.۰%) as major components. The highest percentage of ۱,۸-cineole (۵۱%) was obtained from sample dried in oven ۵۰ °C, while, the highest amount of neptalactone (۵۴.۰%) was obtained from sample dried by the microwave ۱۸۰ W. The results demonstrated that drying the aerial parts of N. binaludensis in the shade and oven ۵۰oC are the best optimal methods to obtain the highest oil yield, while drying in microwave at ۱۸۰ W is recommended to enhance higher neptalactone content in the oil.

Nepeta binaludensis Jamzad, Drying method, essential oil, ۱, ۸-cineole, nepetalactone