ABSTRACT
One of the essential problems of using medicinal plants which are mostly collected from the wild is their fungus and microbial infections. Nowadays, exposing the plants to Gamma radiation apparently removes the problem. But, as the plants contain outstanding amount of chemical substances, the exposition can lead to a change in the composition of the plants chemicals and therefore a change in their medicinal effects. Making poisonous, carcinogen or stimulant substances in the plants could be examples of this change. The aim of this research was evaluating effect of Gamma radiation on chemical composition of ten medicinal plants essential oils; Mentha, Coriandrum, Foeniculum, Zingiber, Cuminum, Bunium, Melissa, Thymus and Zataria. Essential oil of the species before and after Gamma radiation were obtained over Clevenger apparatus, analyzed using GC and GC/MS and identified based on RT, KI and authentic references. Results showed that within ten species, the Coriander oil was affected with the 10 and 25 KG of Gamma radiation and changed to the another components. These results of experiment can alert the world, to the threatening consequences of using Gamma radiation concerning human health