Response surface methodology to supercritical fluids extraction of artemisinin and the effects on rat hepatic stellate cell in vitro

Artemisinin and its derivatives; ancient tradition inspiring the latest therapeutic approaches against malaria

Artemisinin (ART) is an endoperoxide sesquiterpene lactone, commonly used in the treatment of malaria. Although it was isolated from Artemisia annua L., a plant widely applied in Chinese Traditional Medicine, its mechanism of action remains uncertain and its clinical use is still limited due to its low solubility, its poor bioavailability and short in vivo half-life. Over time, several studies have been aimed towards the discovery of potent ART derivatives that could overcome clinical drawbacks. In this review, we focus on the multifaced aspects of ART and on the efforts spent to improve its pharmacological profile that so far culminated in the discovery of more effective drugs. Lastly, we outline the new perspectives in the ART-derivatives scenario.

Production Technologies of Pharmacologically Active Sesquiterpene Lactones

Sesquiterpene lactones form a large group belonging to natural terpenoids series, generally found in plants of Asteraceae family and exhibiting anti-tumor, antiviral, immunostimulant, antifungal, antimicrobial, anti-inflammatory, antimutagenic, growth stimulating, antifeedant effects. Therefore, search for new compounds with a broad spectrum of pharmacological activity in this series provides the opportunities for effective and conceptually new drug design. The basis of the technology for the isolation of sesquiterpene lactones is the extraction of raw materials with various organic solvents, followed by chromatographic purification. Sesquiterpene lactones have no common properties that can be used in their isolation. Some of them are well soluble in non – polar solvents, others-only in polar, in this regard, the methods of isolation of sesquiterpene lactones are diverse. The greatest number of sesquiterpene lactones is isolated from leaves and flowers, slightly less – from roots and bark. Therefore, the development of methods for their isolation is associated with the selection of solvents and optimization of the extraction mode. Unfortunately, very few medicines based on sesquiterpene lactones are produced by the pharmaceutical companies today. Complexity of introduction of pharmacologically active sesquiterpene lactones technology into pharmaceutical production is in imperfection of their isolation methods from plant raw material, their purification and separation from obtained extracts. Production technologies of the patented medicines "Santonin", "Alanton" on the basis of sesquiterpene lactones are multiphase, labor-intensive, implying the use of many toxic organic solvents which is against the international GMP standards.

Optimization of artemisinin extraction from Artemisia annua L. with supercritical carbon dioxide + 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°C), and co-solvent (ethanol, 0-12.6 wt.%). Optimum SC-CO2 extraction conditions were found to be 30 MPa and 33°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.