ABSTRACT
The genus of Diplotaenia presents two species in Iran, D. damavandica and D. cachrydifolia. The first one is endemic of Iran and the second grow wild in lran and Anatoly. In this research, the aerial parts of D. cachrydifolia were collectcd in three stages of plant growth before flowering full flowering and beginning of fruit formation. The plant materials, after drying in room temperature were hydro-distilled for obtaining the essential oils were analyzed by GC and GC/MS. The oils were obtained at yields of 0.93% [before flowering], 4.49% in full flowering and 2.66% [after flowering] based on dry weights of plant materials. Eighteen compounds were identified in the oil of D. cachrydifolia before flowering. The main components were limonene [28.04%], elemieine [15.35%], cis-isoelemieine [15.12%], and apiol [11.78%] and cis-beta- oeimene [10.87%]. In the full flowering stage, eighteen compounds were identified in the oil, with limonene [41.81%], elemieine [21.96%] and cis-beta oeimene [18. 70%] as major constitutents. Twcnty-one components were characterized in the oil of D. cachrydifolia at the beginning of fruit. formation, The main components were limonen [47.63%], clemicine [20.51%], cis-beta-oeimene [8.55%] and I, 8-cineole [5.71%]. The main difference of the essential oils of D. cachrydifolia in these three stages, was that cis isoelemieine disappeared in the oil of full flowering and 1,8-cineole was detected only in the oil of after flowering