Ethanol modified supercritical fluids extraction of scopoletin and artemisinin from Artemisia annua L.

This work studied the supercritical carbon dioxide (SC-CO2) extractions with adding 16.25% ethyl alcohol as a co-solvent to obtain scopoletin and artemisinin from Artemisia annua L. A two-factor central composite experimental design was adopted to determine the optimal operation conditions in extracting the maximal amount of these bioactive compounds. Experimental results indicated that the 289 mu g of scopoletin/g of the feed in dry basis and the 11.6 mg of artemisinin/g of the feed had been obtained at these optimal conditions. Two hours ethanol modified SC-CO2 extractions were superior to 16 h Soxhlet N-hexane extractions in producing more pure artemisinin and scopoletin and the amount of the extracts increased with the density of SC-CO2. A normal phase silica-gel column chromatography to purify artemisinin from the SC-CO2 extract presented that the purity of artemisinin attained 98.2% but with a low recovery of 54.4%. This reduced recovery may be caused by an occurrence of the bridging peroxide atoms of artemisinin reacted with silica-gel molecules during the column purification. (c) 2007 Elsevier B.V. All rights reserved.