An optimized process for SC-CO2 extraction of antimalarial compounds from Artemisia annua L

Supercritical fractional extraction and separation scheme, was used to process Artemisia annua L., producing extracts enriched in active antimalarial principles. The best results were obtained when extraction was performed at 100 bar, 40 °C and the first separator was operated at the same pressure and at −7 °C. Paraffinic co-extracted compounds were selectively recovered in the first separator, confirming the efficiency of the fractional cooling separation and a concentration of 35% w/w of active compounds was obtained in the second separator. Artemisinin was the major active compound in the extract; but, other two active compounds, artemisin and dehydroartemisinin, were also largely found. Other co-extracted compounds belonged to Artemisia essential oil. Different SC-CO2 flow rates were tested: an increase from 0.8 to 1.2 kg/h did not determine appreciable variations of the extraction rate of the various compounds, indicating that internal mass transfer resistance mainly controlled the extraction process.