Chemical composition and antiradical capacity of essential oils from Lebanese medicinal plants

Essential oils from five wild species growing in Lebanon and used in traditional medicine were obtained by hydrodistillation. Their chemical composition was determined by gas chromatography (GC) and GC-mass spectrometry (GC-MS), and the major constituents were α-pinene in Juniperus excelsa M. Bieb. (68.8-86.8%, according to different organs), carvacrol in Thymbra spicata L. (65.8%) and Coridothymus capitatus (L.) Rchb. f. (47%), pulegone in Mentha spicata L. subsp. condensata (Briq.) Greuter & Burdet (32.8%) and 1,8-cineole in Salvia fruticosa (Mill.) K. Schum. (48.7%). Antiradical capacity of the essential oils was measured in vitro by the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTSs+) radical cation and 2,2-diphenyl-picryl hydrazyl (DPPHs) radical assays. A good agreement between the two tests was recorded: C. capitatus and T. spicata oils showed the highest ABTSs+ and DPPHs radical-scavenging activity, possibly due to their high levels of carvacrol, whereas the lowest antiradical capacity was reported for J. excelsa oils.