Changes in Essential Oil Composition of Oregano (Origanum onites L.) due to Diurnal Variations at Different Development Stages

Abstract

The composition of essential oil in plants was affected by genetical and environmental conditions, which is determined by growth region and harvesting time in terms of ontogenetical and diurnal variability. In the present study, aerial parts of Origanum onites were harvested at three different development stages (pre, full and post flowering) and six different times of the day (06:00, 10:00, 12:00, 16:00, 20:00 and 24:00 h). A total of twenty-six components were identified by GC-MS,The major component was carvacrol, followed by thymol, p-cymene and ?-terpinene. The content of carvacrol in the essential oil varied between 24.66 and 52.58% and the highest carvacrol content was obtained from 10:00 h at pre-flowering stages, thymol content changed between 2.80 and 23.77% and the highest thymol content was also obtained from 24:00 h at pre-flowering stages.