The combined extraction of sage (Salvia officinalis L.): Ultrasound followed by supercritical CO2 extraction

A wide spectrum of phytochemicals could be isolated from sage (Salvia officinalis L.) using different extraction or distillation technique: the supercritical fluid extraction (SFE), the volatiles compounds (monoterpenes and sesquiterpenes) isolation using hydrodistillation or higher molecular compounds with Soxhlet extraction or ultrasound-assisted extraction. The combination of ultrasound-assisted extraction followed by re-extraction of obtained extract with supercritical CO2 was performed in this study. The goal of performed investigation was to concentrate diterpenes present in sage extract which are generally considered to be responsible for antioxidant activity of extracted compounds.The fractionation using the supercritical CO2, and different combination of the ultrasound-assisted solvent extractions (water–ethanol mixture or only water) followed by supercritical CO2 re-extraction of obtained extract or treated plant material were analyzed and compared. Based on the results of these investigations it could be proposed the best extraction procedure: the ultrasound pretreatment of plant material with distilled water and re-extraction of plant material (residue) using supercritical CO2. That procedure gives two valuable products: the ultrasound extract which is rich in sugars and possess the immunomodulatory activity and supercritical extract which is rich in diterpenes and sesquiterpenes.