Essential oil composition and chemical variability of Xanthium italicum Moretti from Corsica

The chemical composition of Xanthium italicum Moretti essential oil was established for the first time using gas chromatography and gas chromatographymass spectrometry. One hundred and seven compounds were identified and accounted for 98.7% of the total amount. The main compounds were limonene (35.3%), borneol (5.6%), sabinene (5.8%), germacrene-D (2.5%), a-bisabolol (2.4%) and a-humulene (2.1%). Twenty-five oil samples were investigated, and their chemical variability was analysed statistically. Two main groups of essential oils were identified in concordance with the morphological characteristics: hydrocarbon-rich oils, which correlated with 100120?cm plant height and oxygenated-rich oils, which correlated with 520?cm plant height. The chemical composition of the oils obtained from separated organs and the concentrations of the main compounds throughout the vegetative cycle of the plant were studied. Stem and leaf oils were characterized by the occurrence of limonene (47.9% g and 22.9%, respectively) and germacrene-D (4.6% and 15.8%, respectively). Flower oils displayed d-selinene and germacrene-D as the main components (22.4% and 17.0%, respectively). X. italicum fruits yielded oil with a high amount of oxygenated compounds (72.9%), particularly sesquiterpene compounds (61.5%) such as a-bisabolol (43.0%), a-cadinol (5.0%) and (E,E)-a-farnesol (4.3%). The amount of hydrocarbon compounds remained stable throughout the vegetative cycle, whereas the amounts of oxygenated compounds increased during fructification. Copyright (C) 2012 John Wiley & Sons, Ltd.