Abstract

The chemical composition of the volatile fractions of two populations of Ruta chalepensis L. (Rutaceae) collected, at the vegetative stage, from two areas of the South-East of Tunisia (Sdira and Thoujene) were analysed. The volatile fractions were extracted from the leaves by hydrodistillation or static headspace, then analysed by gas chromatography flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS). Octyl acetate (24.22 to 33.16 %), 2-undecanone (12.43 to 23.82%) and 2-nonanone (14.11 to 41.69%) were found to be major components of the volatiles extracted by hydrodistillation or head space method.Minor components revealed by hydrodistillation were not detected by head space extraction. However, hexadecanoic acid (10.2%) and di(ethylhexyl) phthalate (12.73%) were detected only in headspace of R. chalepensis leaves from Thoujene. Unlike the essential oil, the ethanol andthe aqueous extracts revealed interesting antioxidant activities including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power and metal (Fe²⁺) chelating activity and could be considered as important sources of natural antioxidants.

Key words: Ruta chalepensis, hydrodistillation, headspace, ketones, esters, antioxidant activity.