Extraction of sage (Salvia officinalis L.) by supercritical CO2: Kinetic data, chemical composition and selectivity of diterpenes

The supercritical carbon dioxide (SFE) extraction of Dalmatian sage (Salvia officinalis L.) was investigated and compared to extraction performed by Soxhlet ethanol–water (70:30) mixture extraction (SE) and hydrodistillation (HD). The supercritical extraction allowed isolation of wide spectrum of phytochemicals, while other applied methods were limited to either volatiles (HD) or high molecular compounds isolation (SE). The kinetics of the supercritical extraction and fractionation within the pressure range of 10–30 MPa at 50 °C were also analyzed as well as the chemical compositions of total extract and partial or differential fractions isolated at different CO2 consumption. Volatile fraction could be isolated at low pressure and low CO2 consumption, whereby the pressures between 10 and 15 MPa followed by increased CO2 consumption were favourable for obtaining desired selectivity of diterpenes which contain compounds with expressed antioxidative characteristics.