INVITRO ACTIVITY OF ARTEMISININ, ITS DERIVATIVES, AND PYRONARIDINE AGAINST DIFFERENT STRAINS OF PLASMODIUM-FALCIPARUM

The activities of artemisinin (qinghaosu), dihydroartemisinin (dihydroqinghaosu), artemether and pyronaridine were tested in a 48 h in vitro assay against 3 chloroquine-sensitive and one chloroquine-resistant strains of Plasmodium falciparum. Growth inhibition was modelled with a sigmoid Emax model. All compounds markedly inhibited the growth of all strains although, for the chloroquine-resistant strain, merozoites were detected at concentrations as high as 10a 4m of artemisinin, dihydroartemisinin and artemether. Dihydroartemisinin, artemether and pyronaridine appeared to be more potent than artemisinin, with EC50 values of 4A 7-23 nm, 0A 98-6A 1 nm and 4A 4-18 nm respectively, while the EC50 value of artemisinin was 3 108 nm against all 4 strains. © 1990 Oxford University Press. All Rights Reserved.