Qinghaosu does not affect the major thermotropic phase transition in model membranes of dipalmitoylphosphatidylcholine.

The effect of the antimalarial agent qinghaosu (artemisinin) on the major thermotropic phase transition in bilayer membranes of dipalmitoylphosphatidylcholine has been studied by differential scanning calorimetry and by the use of fluorescent probes (pyrene excimer formation and depolarization of diphenylhexatriene fluorescence). Addition of up to 40 mol% qinghaosu to dipalmitoylphosphatidylcholine bilayer caused no observable effect on the temperature or enthalpy of the phase transition. The results suggest that the antimalarial action of qinghaosu is not due to a direct effect on the lipid structure of the parasite membrane.