Effects of antimalarial drugs on oxygen consumption by erythrocytes infected with Plasmodium berghei: An ESR study

Abstract

Oxygen consumption in mouse erythrocytes infected with Plasmodium berghei has been followed by electron spin resonance (ESR) spectroscopy of nitroxide radical spin probes. The parasitized red cell suspension is mixed with the spin probe CTPO (3‐carbamoyl‐2, 2, 5, 5‐tetramethyl‐3‐pyrrolin‐1‐yloxy) in a closed chamber. Oxygen consumption is monitored by the increasing resolution of the superhyperfine splittings of the spin label. The antimalarial drugs quinacrine, primaquine, and quinine are shown to decrease the rate of oxygen consumption of the parasitized erythrocyte suspensions. The spin‐label method offers advantages over conventional polarographic and spectrophotometric assays for highly parasitized cell populations where cells are fragile and contain oxidized hemoglobin as well as hemoglobin‐derived pigments.