Detection of Antimalarial Activity for New Compounds by Isotopic Microtest

Two clone lines(Dd2 and 3D7) of Plasmodium falciparum were cultivated continuously in human erythrocytes at 37°C in RPMI 1640 medium with human serum and subjected to 6% sorbitol treatment 2 times in order to obtain highly synchronized cultures.The second generation parasites after the treatment were diluted with human RBC to be a suspension of P.falciparum-human RBC at 2.5% hematocrit and 0.5% parasitemia,and 2 μCi/ml of 8-3H-hypoxanthine was added.Isotopic microtest was employed to detect the antimalarial activity for 20 new compounds.Results revealed that the 20 compounds showed no anti-malarial activity,while the control drugs,chloroquine and quinine,exhibited high efficacy,indicating that the isotopic microtest is a stable and reproducible assay for screening new antimalarials.