Phytotoxic activity of Moldavian dragonhead (Dracocephalum moldavica L.) essential oil and its possible use as bio-herbicide

The incessant use of synthetic herbicides may cause several ecological problems including environmental contamination and developing herbicide-resistant species. These concerns led to exploring new eco-friendly weed control strategies. Present study is aimed to assess the phytotoxic activity of Moldavian dragonhead, Dracocephalum moldavica L., essential oil (EO) on Bromus tectorum L. All experiments were carried out as a completely randomized design with three replications. The EO of D. moldavica was analyzed using gas chromatography coupled with mass spectrometry (GC–MS). The outcomes of GC–MS showed that geranyl acetate (32.57 %), geranial (24.50 %), neral (22.65 %), and geraniol (8.78 %) are the major bioactive compounds of EO. As a result of treatment of B. tectorum with EO, seed germination and plantlet growth parameters were reduced in a concentration-dependent manner, and were completely suppressed with an essential oil concentration of 2 μL/mL. The content of pigments was also reduced in a dose-dependent manner. Although, antioxidant enzymes activities were enhanced in low concentrations of the EO, they were inhibited in high concentrations especially at 2 μL/mL. H2O2 and malondialdehyde content as well as electrolyte leakage were enhanced with the increasing concentration of EO. Overall, the outcomes of present study suggest that essential oil of D. moldavica can be used industrially to develop bio-herbicides owing to its noteworthy phytotoxic activity and weed killer potential.