Available online at www.sciencedirect.com Talanta 74 (2008) 930–935 Comparing the effect of sub-critical water extraction with conventional extraction methods on the chemical composition of Lavandula stoechas E. Sultan Giray a,∗ , Saliha Kırıcı b , D. Alpaslan Kaya b,c , Murat T ¨ urk a , ¨ Ozg¨ ur S ¨ onmez a,d , Memet ˙ Inan b a Department of Chemistry, Faculty of Science and Arts, C ¸ukurova University, 01330 Adana, Turkey b Department of Field Crops, Faculty of Agriculture, C ¸ukurova University, 01330 Adana, Turkey c Department of Field Crops, Faculty of Agriculture, Mustafa Kemal University, 31020 Hatay, Turkey d Department of Chemistry, Faculty of Science and Arts, Mersin University, 33030 Mersin, Turkey Received 31 January 2007; received in revised form 18 July 2007; accepted 30 July 2007 Available online 15 August 2007 Abstract The volatile extract composition of Lavandula stoechas flowers obtained by hydrodistillation (HD), subcrtical water extraction (SbCWE) and organic solvent extraction under ultrasonic irradiation (USE) were estimated by gas chromatography–mass spectrometry (GC–MS). One hundred and twenty four components were detected in SbCWE extracts while 94 and 65 signals were gained from HD and USE extracts, respectively. Most of the constituents were identified. The major compounds in all three extracts were fenchon, camphor, myrtenyl acetate, myrtenol and 1,8-cineol, but they differ in quantitatively. The total monoterpene hydrocarbons are higher in HD and USE extracts than those of SbCWE extract. However, SbCWE extract had higher concentration of light oxygenated compounds which contributes to the fragrance of the oil in a major extension. Heavy-oxygenated compounds was also in higher abundance in SbCWE extract (9.90%) than those of HD and USE extracts (3.19 and 4.78%, respectively). Effect of temperature on the extraction yield of SbCWE was investigated and while oil yield was increasing with an increase in temperature, a decrease in the extraction ability of sub-critical water toward the more polar compounds such as, 1,8-cineol, camphor and fenchon, was observed. Kinetic studies shown that SbCWE is clearly quicker than conventional alternatives. Most of components of volatile compounds were extracted at 15 min. © 2007 Elsevier B.V. All rights reserved. Keywords: Sub-critical water extraction; Essential oil; Lavandula stoechas 1. Introduction Lavandula genus is an important member of Labiatae (Lami- aceae) family. Lavandula species are widely distributed in the Mediterranean region and cultivated in France, Spain and Italy. In Turkey, mainly two species, Lavandula stoechas and Lavan- dula angustifolia and their subspecies and hybrid forms grow wildly or are cultivated. Lavandula species are great commer- cial value due to their intense and pleasant aroma. Both the plant material and its essential oil are mainly demanded in perfumery, cosmetic, and food industries. The medicinal importance of the plant is well documented and the drugs prepared from this plant are registered in many Pharmacopeia [1]. The plant is used as ∗ Corresponding author. Tel.: +90 322 338 74 11; fax: +90 322 338 60 70. E-mail address: esgiray@cu.edu.tr (E.S. Giray). expectorant, antispasmodic, carminative, a good stimulan, deob- struent, resoluent and wound healing. The essential oil obtained from its flowering twigs has been used as a remedy against colic and chest affections, to relieve nervous headache, bliousness and for cleansing wounds [2]. With better understanding of natural products, researchers have become interested in studying the active natural products as medicine, food additives or as natural pesticides [3]. The pharmaceutical studies of natural products are one of the most interesting and active research areas. Since pharmacologically active compounds in herbal plants usually are in low concen- tration, a great deal of research has been done to develop more effective and selective extraction methods for recovery of these compounds from the raw materials. The conventional methods used to prepare essential oils are steam distillation and solvent extraction. Steam distillation is also most used methods to pre- pare essential oils on a commercial basis. However, there are few 0039-9140/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.talanta.2007.07.040