In vitro application of chitosan effects on essential oil content and physiological characteristics of Dracocephalum kotschyi Boiss

D. kotschyi is a source of essential oils with medicinal properties such as antihyperlipidemic, immunomodulatory, antinociceptive and cytotoxic effects. This study aimed to investigate whether the application of chitosan can improve plant growth, increase secondary metabolite production and help antioxidant enzymatic systems in Dracocephalum kotschyi under in vitro culture. Tow-week-old seedlings of D. kotschyi were cultured in MS medium containing 0, 5, 10 and 20 mg.L-1 chitosan. Four weeks after treatments, the enzymatic and morphological parameters were measured and the GC/MS analysis was used to evaluate the secondary metabolites. Chitosan resulted in changes in physiological and morphological responses. It had a beneficial effect on the main essential oil contents such as thymol, p-cymene and candinol increased by 16.2%, 20.3% and 34%, respectively. In spite of reduction of antioxidant  activities and growth, 20 mg/l had a positive effect on the oil components in D. Kotschyi.