ELSEVIER Journal of Chromatography A, 785 (1997) 353-360 JOURNAL OF CHROMATOGRAPHY A Extraction of artemisinin and artemisinic acid from Artemisia annua L. using supercritical carbon dioxide Marcel Kohler a, Werner Haerdi a, Philippe Christen b, Jean-Luc Veuthey b'* ~University of Geneva, Laboratory of Mineral. Analytical and Applied Chemistry. 30. quai Ernest Ansermet. CH-1211 Geneva 4, Switzerland bUniversiO~ of Geneva, Laborato©" of Pharmaceutical Analytical Chemisto,. 20, bd. d'Yvoy, CH-1211 Geneva 4, Switzerland Abstract Artemisinin (an antimalaric compound) and its major precursor artemisinic acid, isolated as the active principles of the medicinal plant Artemisia annua L., were extracted by supercritical fluid extraction (SFE) and analyzed by supercritical fluid chromatography (SFC) using a capillary column, coupled with a flame ionization detector (FID). With optimized operating conditions, artemisinin and artemisinic acid were quantitatively extracted at a flow-rate of 2 ml min ~ in less than 20 min. The supercritical fluid was composed of carbon dioxide and 3% methanol with temperature and pressure fixed at 50°C and 15 MPa, respectively. From the kinetic curves, it appears that the extraction of artemisinin is not limited by the diffusion of the analyte from the plant into the extraction fluid but rather by the elution process. These conditions avoided degradation of the analyte and gave clean extracts ready to be analyzed by SFC. The SFE-SFC-FID method was successfully applied to six samples of A. annua containing various concentrations of artemisinin and artemisinic acid. Results were compared with two conventional liquid solvent extraction processes. © 1997 Elsevier Science B.V. Keywords: Artemisinin; Artemisinic acid 1. Introduction Malaria is a major disease in many countries, since, according to an estimation of the World Health Organisation (WHO), approximately 300 to 500 million people contract malaria yearly and almost 2 million die annually [1]. Controlling malaria is now becoming very problematic in view of the develop- ing resistance of Plasmodium falciparum to chloro- quine, mefloquine and other commonly used antima- larial drugs [2]. Therefore, it is vital to investigate new antimalarial compounds. Artemisinin is a promising drug against chloro- quine-resistant strains of P. falciparum and in the Corresponding author. 0021-9673/97/$17.00 © 1997 Elsevier Science B.V. All rights reserved. PII S0021-9673(97)00403 2 treatment of cerebral malaria [3-5]. This compound is an endoperoxide sesquiterpene lactone (Fig. 1) found in the aerial parts of the plant Artemisia annua L. (Asteraceae), a plant which has been used for many centuries in traditional Chinese medicine for the treatment of fever and malaria. Although the total CH H , 3 O ~ C H ~ 0 O H'w I H O ~CH 3 O CH 3 [ CH3 ] HOOC" CH 2 ARTEMISININ ARTEMISINIC ACID Fig. I. Structures of artemisinin and artemisinic acid.