Comparison of the Volatiles of Achillea millefolium L. Obtained by Supercritical Carbon Dioxide Extraction and Hydrodistillation Methods

The volatiles of Achillea millefolium L., cultivated in Iran, were obtained by hydrodistillation and supercritical (carbon dioxide) extraction methods'. The volatiles were analyzed by capillary gas chromatography using flame ionization and mass spectrometric detections. The effects of different parameters, such as pressure, temperature, modifier volume and extraction time, on the supercritical fluid extraction (SFE) of A. millefolium volatiles were investigated. The results showed that, under a pressure of 300 atm, temperature 35 degrees C, 5% methanol and dynamic extraction time of 20 min, extraction was more selective for germacrene D. Fifty compounds, were identified in tire hydrodistilled oil. The major volatile components of A. millefollium were 1,8-cineole (15.2%) and germacrene D (14.1%). However, by using supercritical carbon dioxide under optimum conditions, only two components constituted more than (60%) of the volatile concentrate.