Optimization of artemisinin extraction from Artemisia annua L. with supercritical carbon dioxide plus ethanol using response surface methodology

Malaria is a high priority life-threatening public health concern in developing countries, and therefore there is a growing interest to obtain artemisinin for the production of artemisinin-based combination therapy products. In this study, artemisinin was extracted from the Artemisia annua L. plant using supercritical carbon dioxide (SC-CO2) modified with ethanol. Response surface methodology based on central composite rotatable design was employed to investigate and optimize the extraction conditions of pressure (9.9-30 MPa), temperature (33-67 degrees C), and co-solvent (ethanol, 0-12.6 wt.%). Optimum SC-CO2 extraction conditions were found to be 30 MPa and 33 degrees C without ethanol. Under optimized conditions, the predicted artemisinin yield was 1.09% whereas the experimental value was 0.71 +/- 0.07%. Soxhlet extraction with hexane resulted in higher artemisinin yields and there was no significant difference in the purity of the extracts obtained with SC-CO2 and Soxhlet extractions. Results indicated that SC-CO2 and SC-CO2+ethanol extraction is a promising alternative for the extraction of artemisinin to eliminate the use of organic solvents, such as hexane, and produce extracts that can be used for the production of antimalarial products.