ANTIMALARIAL ACTIVITY OF NOVEL ARYLENE BIS(METHYLKETONE) COMPOUNDS

Because of the spread of drug-resistant Plasmodium species, there is a n urgent need for novel effective antimalarial agents. A series of ary lene bis(methylketone) compounds were screened in vitro against a numb er of Plasmodium falciparum clones and in vivo against Plasmodium berg hei, (3,5-diacetylphenyl)amino-1,6-dimethylpyrimidinium chloride (Cyto kine Network Inc. [CNI]-H0294) was the most effective of the compounds in vitro, with an IC50 Of 1.5-4.0 mu M against parasite clones with a wide range of sensitivities to chloroquine and pyrimethamine, Other c ompounds in the series had in vitro IC50 values of 20-25 mu M, In a 4- day test for suppression of P. berghei parasitemia in vivo, 50 mg/kg/d ay CNI-H0294 significantly decreased parasitemia by >90%, The compound was found to have low toxicity in mice, with an LD(50) Of 590 +/- 66 mg/kg intraperitoneally, and rapid plasma kinetics. These results show that CNI-H0294 has considerable antimalarial activity and merits furt her study.