Chemical composition and antimicrobial activity of the essential oil of Conyza canadensis (L.) Cronquist from Turkey

The essential oils obtained from the aerial parts and the roots of Conyza canadensis (L.) Cronquist (Asteraceae) at the flowering stage, collected from Turkey were simultaneously analysed by GC-FID and GC-MS. Forty-six components comprising 82.8% of the essential oil from the aerial parts and seven components comprising 96.7% of the roots oil were identified. Major constituents of the essential oil of the aerial parts were found to be limonene (28.1%), spathulenol (16.3%) and β-pinene (9.7%), whereas cis-lachnophyllum ester (86.5%), (2Z,8Z)-matricaria ester (3.9%) and β-pinene (2.3%) were identified to be main constituents in the volatiles of the root parts. In addition, antimicrobial activity of the essential oils was screened against Gram-positive and Gram-negative bacteria as well as one strain of fungus by broth microdilution method. Both of the essential oils exhibited antifungal activity against Candida albicans ATCC 10231 with 0.078 μg/ml MIC values. The highest antibacterial activity was observed by aerial parts oil against Escherichia coli RSKK 234 (MIC: 0.039 μg/ml). This is the first report on the chemical composition and antimicrobial activity of the essential oils obtained from C. canadensis growing in Turkey.