ABSTRACT
Background: The post-harvesting process of medicinal plants such as drying operation and storage conditions has great influence on their quality and quantity of the active ingredients
Objective: The aim of this experiment was to investigate the effect of pre-drying operation and also storage conditions and duration on the essential oil content and composition of Thymus daenensis
Methods: A factorial experiment was conducted based on randomized complete block design with three replications. The first factor include drying operations [including pre-drying and without pre-drying], the second factor include storage method [shade storage and storage in a refrigerator at 4 degree C], and the third factor was storage duration [storing the plants organs for 60, 120 and 180 days]. The essential oil was extracted by clevenger apparatus and its components were identified using GC and GC/Mass
Results: The highest amounts of essential oil, linalool, borneol, terpinene-4-ol, thymol methyl ether, e-anethol, thymol and carvacrol were observed in plants stored for 60 days. Also, the highest amounts of a-pinene, camphen, Beta pinene, myrcene, a-phellandrene, a-terpinene, limonene, cis-sabinene hydrate and trans-sabinene hydrate were observed in the plants dried in the shade after pre-drying operation and stored in the refrigerator for 120 days
Conclusion: Drying of T. daenensis plants under shade without pre-drying operation and storing in 4 degree C was the best way to obtain the highest amounts of essential oil and its main components [thymol and carvacrol]