determine optimum of harvest time on the quantity/quality of essential oil and thymol of thyme (thymus vulgaris l.) in isfahan

background & aim: thyme is common named thymus vulgaris l. belongs to lamiaceae family. thyme is a most important medicinal plant that was used in pharmaceutical, food, cosmetics hygienic industries in most of developed countries. experimental: determine optimum of harvest time this plant was done in a random block design with three replications was conducted in field islamic azad university of khorasgan (isfahan) 2009 and 2010. treatment phonological stages such as: 1) before flowering stage; 2) at beginning of flowering stage; 3) 50% blooming stage; 4) at full flowering step and 5) at fruit set stage. the essential oil obtained by hydro-distillation using a clevenger- type apparatus and, was analyzed by gc and gc/ms. results & discussion: statistic analysis showed that the effects phonological stages had significant effect on essential oil yields & percent, thymol. the highest essential oil content (2.42%) was extracted at the beginning of flowering stage. analysis and identification of components showed thymol main compounds in all samples. industrial/practical recommendation: according to the results of this project 50% blooming stage optimum of harvest time on the quantity/quality of essence and thymol of thyme.