Effect of harvesting time on quantity and quality of essential oil in Thymus lancifolius and T. armeniacus

Thymol and carvacrol are two valuable secondary metabolites which are importance in medicinal use. This study aimed to investigate the effect of different harvesting times (pre blooming, 50% in blooming and 100% in blooming) on quantity and quality of T. armeniacus and T. lancifolius essential oil in pot experiment by using a completely randomized design in three replications during 2015 from Shahrekord University. The aerial parts of plants were collected in three times and the essential oils were extracted by hydro distillation (Clevenger apparatus) and were analyzed by using GC/MS. . The results were showed that in full blooming stages of plants had the highest of essential oil yield. The highest content of thymol (62%) was obtained in pre blooming and citronelol (30%) in 50% and full blooming of T. lancifolius. The highest carvacrol (44-45%) were obtained in 50% and full blooming stage of T. armeniacus, respectively. In conclusion, the variation species and harvesting times of plants were affected on quality and the function of essential oils.