Ruta chalepensis L. Essential Oil: Chemical Composition and Phytotoxic Activity Jamel Mejri 1, 3, *, Jalloul Bouajila 2 , Safouane Ben Sik Ali 3 , Manef Abderrabba 1 , Mondher Mejri 4 1 Unité de recherche en physico-chimie moléculaire, Institut Préparatoire des Etudes Scientifiques et Techniques, IPEST, BP51, La Marsa 2070, Tunisia 2 Laboratoire de Synthèse et de Physicochimie de Molécules d’Intérêt Biologique, UMR CNRS 5068, Université Paul-Sabatier, 118 route de Narbonne, F-31062 Toulouse, France 3 Département de Génie des Procédés, Institut Supérieur des Etudes Technologiques de Bizerte, 7035 Menzel Abderrahmen, Tunisia 4 Département de Génie des Procédés, Institut Supérieur des Etudes Technologiques de Zaghouan, 1121 Mograne, Tunisia Abstract: The aim of this work is to study the use of Ruta chalepensis essential oil as a bioactive substance in order to propose ways of valuation and rational exploitation of the plant. In this context, the extraction of essential oil was carried out using hydrodistillation process. 23 compounds were identified in the aerial part of Ruta chalepensis essential oil. The major compound is undecan-2-one (77.7 %). In addition, the phytotoxic activity of Ruta chalepensis essential oil was investigated. An important toxicity on the germination of the hard wheat was observed. Indeed, the rate of hard wheat germination passes from 65.55 % at 0.5 μl.ml - 1 essential oil concentration to 31.11% at 1 μl.ml -1 . Key words: Ruta chalepensis L., essential oil, hydrodistillation, undecan-2-one, phytotoxic activity. Introduction Ruta chalepensis L. is a wild plant that grows in Tunisia. It is cultivated in some gardens for decoration and for use in traditional herbal medicine. A phytochemical screening of Ruta species characterized the presence of alkaloids, flavonoids, coumarins, tannins, volatile oil, glycosides and terpene as possible bioactive compounds 1 . Indeed, flavonoids, glycosides and tannins are considered as potential inhibitors of pro-inflammatory molecules 1, 2 . Indeed, Ruta species are resources of various classes of natural products with biological activities: antifungal, antioxidant, phytotoxic, abortifacient, antidepressant, antidote, anti- inflammatory 1, 2, 3, 4, 5, 6, 7, 8, 9 . Ruta species are studied for the production of furanocoumarins 3 . Ruta graveolens Ruta chalepensis, Ruta montana and Ruta angustifolia. Furanocoumarins are used in dermatology and for the treatment of other diseases. The seeds of Ruta angustifolia and Ruta Montana are difficult to germinate. This inhibition may be due to the high concentration of furanocoumarins. Ruta Journal of Biologically Active Products from Nature ISSN Print: 2231-1866 Online: 2231-1874 www.jbappn.com *Corresponding author (Jamel Mejri) E-mail: < jmejri2001@yahoo.com > © 2012, Har Krishan Bhalla & Sons