ABSTRACT. Artemisinin, a sesquiterpene lactone derived from Artemisia annua, is a potent antimalarial agent whose mechanism is believed to involve peroxide bond cleavage catalyzed by transition metals. Hemin, inorganic iron, and hemoglobin have all been proposed as primary mediators of this activation through free radical formation. This study aimed to compare the ability of these biological species to induce artemisinin-derived radicals using electron spin resonance (ESR) spectroscopy. Extracted artemisinin was tested in systems containing horseradish peroxidase (HRP) and hemoglobin. While radical generation was confirmed in the presence of hemoglobin, unexpected radicals were also detected in solvent-only controls, particularly with absolute ethanol, complicating interpretation. These results highlight the need for further investigation into solvent-specific radical contributions and refinement of experimental controls when studying artemisinin activation pathways.

 

Keywords: Artemisinin, ESR, hemoglobin, hemin, peroxide cleavage, radical formation, malaria