Extraction of essential oils of leaves and flowers of Achillea monocephala by superheated water

Superheated water extraction at temperatures of 100 degrees C, 125 degrees C, 150 degrees C and 175 degrees C was applied to extract the essential oils of Achillea monocephala leaves and flowers. The compositions of the essential oils, obtained using superheated water at various temperatures, were characterized by comprehensive GC-time of flight mass spectrometry (TOF-MS). The highest essential oil yields were obtained at 150 degrees C, 2 ml/min and 60 bar for 30 min, and were 2.90% and 1.58% for the leaves and flowers, respectively. The major compounds were camphor and borneol for the leaf oil and camphor, borneol, 1,8-cineole and alpha -campholenal for the flower oil. Extraction with superheated water was completed in the first 20 min at 150 degrees C. Copyright (c) 2005 John Wiley & Sons, Ltd.