Volatile Compounds of Fennel Leaves Obtained by Hydrodistillation and Supercritical CO ₂

Background/Objective Fennel is a Mediterranean perennial herb growing near the sea on calcareous soils in full sunlight. The objective of the study was to identify chemical compounds present in fennel leaves obtained by two different extraction methods. Methods The fennel leaves were extracted by hydrodistillation and supercritical CO 2 extraction. The chemical composition of the essential oils obtained were analyzed by gas chromatography-mass spectrometry. Results The essential oil yield of fennel leaves obtained by hydrodistillation was 0.8% and of the essential oil obtained by supercritical CO 2 extraction was 0.5%. The main chemical compounds of the essential oil obtained by hydrodistillation were: oxygenated monoterpenes (75.05%), monoterpene hydrocarbons (7.97%) and sesquiterpene hydrocarbons (3.72%). The most dominant compounds of the essential oil obtained by supercritical CO 2 extraction were: oxygenated monoterpenes (57.52%), sesquiterpene hydrocarbons (12.18%) and oxygenated sesquiterpenes (9.37%). Conclusion The hydrodistillation is a method of choice for obtaining oxygenated monoterpenes, especially anethole which represents 65.77% of the whole essential oil compared to the essential oil obtained by supercritical CO 2 extraction where anethole was present in 20.16%.