Effect of heavy metal stresses due to Nichel and Cadmium concentrations on extract composition of Thymus persists

Thyme is one of the high consuming medicinal plant in Iran and Thymus persicus is an Iran endemic thyme species which grows in heavy metal contaminated areas of Zanjan province. In order to study of the effect of Nickel and Cadmium on the secondary compounds of Thymus persicus, seedlings were cultured in different concentrations of Ni and Cd: 0 (control), 0.2, .04 and 0.6 mM in a hydroponic culture system. Three weeks after treatment, the N-Hexane extract of aerial parts of plants at control and heavy metal stress treatments were analyzed using GC/MS. According to the results; thymol, thymoquinone, linalool and formic acid were the main components of the extract at the control treatment. The percentage of thymol increased at all Ni and Cd concentrations except for the 0.4 mM Ni, however; the amount of thymoquinone, linalool and formic acid decreased at all heavy metal treatments comparing to control. It can be suggested that Ni and Cd had different effects on extract composition in this plant. Some major compounds of extract increased and some decreased which showed unpredictable consequences.