Supercritical CO2 extraction of Salvia officinalis L.

Dry sage leaves were extracted with dense carbon dioxide under the following conditions: pressure, 9–12.8 MPa; temperature, 25–50 °C; sage feed, 3–4 g; carbon dioxide flow rate, 0.05–0.35 g/min; solvent-to-feed ratio, 16–21. The oil in finely ground particles was easily accessible to the solvent and its extraction was controlled by phase equilibrium. A part of essential oil dissolved in CO2 almost immediately, the other part was extracted gradually together with cuticular waxes and water. The difference in extraction rate was connected with essential oil fractionation due to the different solubility of oil components and solute–matrix interaction in the second extraction period. Collection efficiency of a cooled glass U-tube at ambient pressure was low for volatile substances but good for sesqui- and diterpenes. The extraction yield of oxygenated monoterpene manool was more than double its yield obtained by hydrodistillation.