Supercritical extraction of Hypericum caprifoliatum using carbon dioxide and ethanol + water as co-solvent

Hypericum caprifoliatum is a natural source of phloroglucinol derivatives such as hyperbrasilol B, uliginosin B and japonicin A, compounds with pharmaceutical interest due to principally their antidepressant properties. This work studies supercritical fluid extraction to obtain non-volatile compounds from the aerial parts of H. caprifoliatum as well as the influence of the co-solvent as agent of process intensification. The experimental procedures were carried out in a pilot unity. The mathematical simulation of the experimental data was performed by mean of three mathematical models aiming to promote the improvement of the knowledge about this technology. The feasibility of the mathematical model was investigated by mean of fitting of the experimental data obtained. The co-solvents tested were ethanol, water, and water–ethanol mixtures.     

Extraction of bioactive enriched fractions from Eruca sativa leaves by supercritical CO2 technology using different co-solvents

Supercritical fluid extraction from freeze-dried Eruca sativa leaves is assessed with the aim of studying the feasibility to obtain bioactive enriched fractions containing different classes of valuable compounds. Total extraction yields and compositions using pure CO₂ and CO₂ + selected co-solvents are compared. Overall extraction curves, fitted by the model of broken and intact cells developed by Sovová, are reported and the influence of the main parameters that affect the extraction process is analysed. The extract with the highest content in glucosinolates and phenols was collected at 30 MPa and 75 °C using 8% (w/w) of water with respect to the CO₂ flow rate, whereas the fraction richest in lipids was obtained using 8% (w/w) of ethanol as co-solvent at 45 °C and 30 MPa. A process including a first step with supercritical CO₂ extraction using water as co-solvent followed by a second step, where a fraction rich in lipids is extracted using ethanol as co-solvent, is proposed. SCCO₂ results are compared with Soxhlet and other methods that combine organic solvents with ultrasounds.