Effects of different ecological conditions and extraction techniques on the quality of volatile oils from flaxleaf fleabane (Erigeron bonariensis L.)

The objective of this study was mainly to compare the chemical composition of essential oils from the whole parts of Erigeron bonariensis obtained by traditional hydrodistillation technique and by supercritical fluid extraction recognized as an alternative efficient method. A comparison of the effects of different ecological conditions on the chemical composition of essential oil samples collected in different localities, Monastir (Tunisia) and Cagliari (Sardinia, Italy), has been also performed. Thus, interestingly gas chromatography/mass spectrometry (GC/MS) analysis showed that the volatile fraction prepared by supercritical fluid extraction from Tunisian E. bonariensis was richer in terpenes components (90.6%) compared with the essential oil obtained by traditional hydrodistillation (86.2%). Chemical analysis revealed that although roughly the same compounds were extracted using both supercritical fluid extraction (SFE) and hydrodistillation (HD) but with different percentages. Furthermore, the essential oil of Tunisian E. bonariensis obtained by traditional hydrodistillation has high content of caryophyllene oxide (18.7%), spathulenol (18.6%) and α-curcumene (10.2%) whereas Sardinian essential oil was richer in Cis-lanchnophyllum ester (14.2%) and (E)-β-farnesene (12.0%).