Chemical Composition and Antimicrobial Activity of the Essential Oil of Ruta chalepensis L. Growing Wild in Lebanon

The essential oils (EOs) isolated from the fresh aerial parts of Ruta chalepensis L. collected in North Lebanon were obtained by solvent-free microwave extraction (Milestone (R)), yielding 0.12% EO from both the leaves and a mixture of stems and leaves. The EOs were characterized by GC/MS analysis, and 27 components were identified, which were primarily ketones (88.0-93.2%). The main components were nonan-2-one and undecan-2-one. The antimicrobial activity of the EOs against a Gram-positive and a Gram-negative bacterium, a yeast, and a dermatophyte was evaluated using the broth-microdilution technique and expressed as minimal inhibitory concentration (MIC). The EOs revealed moderate in vitro antifungal activity against Trichophyton rubrum and Candida albicans.