Supercritical fluid extraction of curry flowers, sage leaves, and their mixture

Yield and composition of curry flower (Helichrysum italicum) and sage leaves (Salvia officinalis) extract obtained by supercritical CO2 extraction (SFE) at 15 MPa and 40 °C were analyzed and compared to composition of curry flowers and sage essential oil isolated by hydrodistillation. Furthermore, the SFE performed using a mixture of curry flowers and sage plant and SFE of mixture of curry flowers and essential oil of sage were analyzed, too. It was shown that the average selectivity of monoterpenes and some individual sesquiterpenes and diterpenes present in pure sage or pure curry extract were significantly changed when mixture of these plants was used for SFE. The goal of SFE realized with mixture of curry flowers and sage essential oil was to explain effect of essential oil used as co-solvent changing the solubility of different compounds or characteristic group of terpenes in supercritical CO2. Increased extraction of heavier compounds from curry flower which is actually not present in pure essential oil of sage was also detected. The pseudo-kinetic model was proposed and corresponding parameters which define the rate of extraction were determined and compared to the parameters obtained according to Sovovaʹs model usually used in literature for predicting yield of SFE from different plants.