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 μg 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.