The supercritical CO2 extraction of four different plants from Lamiaceae family, namely oregano (Origanum vulgare), thyme (Thymus zygis), sage (Salvia officinalis) and rosemary (Rosmarinus officinalis) was carried out in an experimental pilot-plant comprising an extraction cell of two liters capacity. 600 g of leaves of each plant material, with the same pre-treatment, were extracted at the same pressure and temperature (30 MPa and 313 K) and using 2.4 kg/h of CO2. Further, the same fractionation procedure in a two on-line decompressing separators at, respectively, 10 MPa and 0.1 MPa was employed. In this way, a thoughtful comparison of the extraction kinetic was established and discussed, in terms of the extraction yields attained in the separators, the variation of the essential oil composition with time and the content of key bioactive substances identified in the different fractions

This is the author’s version of a work that was accepted for publication in Journal of Supercritical Fluids. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in The Journal of Supercritical Fluids 64 (2012): 1-8 http://dx.doi.org/10.1016/j.supflu.2012.01.006

The authors gratefully acknowledge the financial support from the Comunidad Autónoma de Madrid (ALIBIRD, project number S-2009/AGR-1469) and the Ministerio de Educación y Ciencia (CONSOLIDER-INGENIO, CSD 2007-00063)