Chemical composition and in vitro antimicrobial activity of the essential oil of the flowers of Tridax procumbens.

The essential oil of the flowers of Tridax procumbens L. was obtained by hydro-distillation and analyzed by gas chromatography equipped with a flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS). Twenty-six compounds were identified, which comprised 90.6% of the total constituents. The most abundant compound was (Z)-falcarinol (25.9%), followed by alpha-selinene (15.3%), limonene (8.3%) and zerumbone (4.3%). Antimicrobial activity was tested against six Gram-positive and eight Gram-negative bacteria, and three fungi. The oil was active against the tested Gram-positive bacteria at a concentration range of 0.14 +/- 0.03 - 0.57 +/- 0.05 mg/mL, while 0.67 +/- 0.12 - 4.58 +/- 0.41 mg/mL was effective against the studied Gram-negative bacteria. Remarkable antifungal activity was found against the tested fungi at a concentration range of 0.06 +/- 0.008 - 0.10 +/- 0.01 mg/mL.