Chemical composition, antimicrobial and antioxidant activities of the essential oil of Conyza canadensis growing wild in Kashmir valley

Chemical composition of the essential oil of Conyza canadensis has been carried out using Gas chromatography-mass spectrometry (GC-MS). A total of 26 components, constituting 93.94% of the total volatile constituents present in the aerial part, have been identified. The hydrodistilled extract of the aerial part of C. canadensis was dominated mainly by monoterpene hydrocarbons (53.08%) followed by sesquiterpene hydrocarbons (37.25%). The major components identified in the essential oil were limonene (23.78%), (Z)-lachnophyllum ester (21.25%), (E)-β-ocimene (16.02%), β-pinene (11.83%) and (E)-β-farnesene (7.84%). The essential oil and the individual constituents exhibited significant antibacterial activity against the tested Gram-positive and Gram-negative food-borne bacteria with MIC values in the range of 12.00-40.00 μg/mL for the essential oil and 32.00-600 μg/mL for the individual constituents, respectively. The essential oil showed maximum inhibitory activity against Candida albicans and Candida parapsilosis with MICs of 2.50 and 1.80 μg/mL, respectively. The essential oil showed promising antioxidant activity using DPPH (2, 2-diphenyl-1-picrylhydrazyl) and hydroxyl radical scavenging assays.