Effects of altitudes on secondary metabolite contents of Origanum majorana L.

Altitude is an important ecological factor that significantly affects essential oil content, yield and composition. The Origanum majorana , belonging to Origanum genus of Lamiaceae family, is a species with antibacterial and antiviral effects, widely used as a spice and also used in folk medicine for treatment of diseases such as asthma, indigestion, headache and rheumatism. In this study, conducted to examine the effects of altitude on essential oil content and composition of origanum majorana , plant samples were collected from the southern region of Turkey at the beginning of flowering period from seven different altitudes (766 m, 890 m, 968 m, 1079 m, 1180 m, 1261 m and 1387 m) at 100 m intervals. The highest percentage of essential oil (6.50%) obtained by hydro-distillation was determined at 766 m altitudes. The GC-MS analyses revealed that low altitude affected some essential oil components positively. The linalool ratio, which is the major component of the essential oil of Origanum majorana species, was the highest at 766 m (79.84%) altitudes. Borneol (0.97%), linalool oxide (1.28%), trans-linalool oxide (1.47%), caryophyllene (2.78%), a- humulene (0.21%), germacrene-D (0.31%) and bicyclogermacrene (2.64%) components yielded high values at 890 m altitudes. Thymol (6.28%) and a-terpineol (1.04%), which have an important place in the essential oil composition, increased at 1180 m altitudes; a- terpinene (0.17%), cis-sabinene hydrate (0.82%), terpinene-4-ol (0.55%) and carvacrol (21.50%) increased at 1387 m altitudes.