ESSENTIAL OIL COMPOSITION OF THYMUS FALLAX FISCH. & C.A. MEY. AT DIFFERENT GROWING ALTITUDES IN MAZANDARAN, IRAN

Thymus fallax Fisch. & C.A. Mey. (Lamiaceae) is a permanent plant that grows in some mountain rangelands of Mazandaran province in Iran. The aerial parts of Thymus fallax were collected during flowering stage from mountain rangelands of Mazandaran province, in North of Iran. Around samples were collected from three altitudes (2400 m, 2700 m and 3000 m a.s.l.), in mountain regions of Mazandaran province. The goal of current research was to assess the effect of altitude on the chemical composition and function of essential oil in Thymus fallax. The essential oil was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas spectrometry (GC-MS). Based on the results, the essential oil content is between 1.12 - 1.61% at different altitudes. The result of study shows that the highest concentrated essential oil (1.61%) was extracted in the lowest altitude (2400 m), while it was opposite, (0.1.12%) in the highest altitude (3000 m). The main compounds of essential oil are: thymol (5.95% - 10.06%), carvacrol (13.63% - 69.04%), p-cymene (4.19% - 12.18%) and borneol (4.72% - 5.66%). According to the results, altitude has a negative effect on the percentage of essential oils and essential oil decreases with increasing altitude. The altitude has a negative effect on the percentage of thymol and the content of thymol decreased with increasing altitude. The altitude has a positive effect on the percentage of carvacrol and the content of carvacrol increased with increasing altitude.