Subcritical water extraction of essential oils from Thymbra spicata

Essential oils from the leaves of Thymbra spicata L. were extracted using subcritical water. The extraction efficiencies of different temperatures (100, 125, 150 and 175 degreesC), pressures (20, 60, and 90 bar) and flow rates (1, 2, and 3 ml min(-1)) were investigated. The components of essential oils of Thymbra spicata were removed from the aqueous extract by C18 solid phase extraction. The identification of components was carried out using two-dimensional gas chromatography (GC)- Time of flight/Mass Spectrometry (TOF/MS). The essential oil yields were found to be 2.5, 2.7, 3.7, 3.5% for 100, 125, 150 and 175 degreesC, respectively. Subcritical water extraction of essential oils from Thymbra spicata exhibited the highest extraction efficiency at 150 degreesC, 2 ml min(-1) and 60 bar for 30 min. The minimum time for a complete extraction of the leaves of Thymbra spicata was 20 min at 150 degreesC and 2 ml min(-1). (C) 2003 Elsevier Science Ltd. All rights reserved.