Contribution to the study of the chemical variability of the essential oils of the seeds and the stems in some populations of Pituranthos tortuosus (Coss.) Maire from Tunisia

Abstract

The aim of this study was to investigate the variation of the chemical composition of the seeds and stems essential oils of Pituranthos tortuosus (Coss.) Maire collected from three regions of Tunisia (Bousaid (Sfax), Rgeb (Sidi Bouzid) and Majoura (Gafsa)). The seeds and the stems were hydrodistillated during 4 h by using a Clevenger-type apparatus. The obtained essential oils were analyzed by GC and GC-EI-MS. The chromatographic analysis indicated the detection of sixty-seven components accounting from 97.5% to 99.7% of the whole of each essential oil with a predominance of monoterpene hydrocarbons (from 38.2% to 66.1%). So, a strong predominance of the monoterpene fraction was observed in the seeds (75.8%; 60.6%; 90.8%) and the stems (89.7%; 91.7%; 89.7%) essential oil of P. tortuosus collected from Majoura, Bousaid and Rgeb, respectively. However, sabinene (19.4%; 11.8%; 24.7%) and terpinen-4-ol (16.9%; 22.9%; 19.2%) were the most abundant compounds of the essential oil of seeds and stems of Rgeb as well as the essential oil of the stems of Majoura, respectively, whereas the major components of the seeds of P. tortuosus collected from Majoura were limonene (25.1%), sabinene (18.6%) and apiol (13.4%). The stems essential oils of Bousaid were dominated by terpinen-4-ol (32.3%), sabinene (23.6%) and p-cymene (10.9%) while dillapiole (34.7%), limonene (14.3%), sabinene (12.6%) and terpinen-4-ol (10.4%) were the main components of the essential oil of the seeds collected from Bousaid. Based on the main compounds, the essential oils of seeds and stems of P. tortuosus from the three regions of Tunisia displayed different chemical compositions.