The effects of ecological factors on essential oil yield and composition of Ziziphora clinopodioides lam.Subsp.rigida(Boiss) Rech.f.

Ziziphora clinopodioides is one of the aromatic and medicinal plants belong to Labiatea family. The essential oil of this plant contains pulegone with many medicinal properties. The aim of this study was identification of natural habitats of Z. clinopodioides In Hamedan province and effects of ecological factors on it’s essential oil content and composition. So the aerial parts of Z. clinopodioides were collected from 11 localities at flowering stage and dried in shade and room temperature. Some ecological factors like geographical characters، height، slope percent and other plant species were determined. The soil of each collection site from 30 Cm depth was also analyzed. The plant materials were subjected to hydro-distillation for extraction their essential oils in three replications. The oil yields were calculated based on dry weight. The chemical constituents of essential oils were identified by using GC and GC/MS. The results showed that oil yields have significant difference at % and 5% levels. The highest oil yield was observed for Z7 and the lowest for Z11. Twenty six components were identified in the oils that the percentage of main compounds، pulegone and 1،8-cineole، was different in samples from different localities that showed the effect of ecological factors.