The effects of cordycepin on malaria parasites

The effects of cordycepin (3′-deoxyadenosine) both on cultures of the erythrocytic stages of Plasmodium knowlesi incubated in vitro and Plasmodium berghei berghei in vivo have been studied. Concentrations of drug as low as 106M affected the growth in vitro of the parasite after a lag period of about 4 hours. These effects could be partially prevented by adenosine but not by other purines tested. Of the various anabolic and catabolic processes studied in the malaria parasite in vitro, the drug affected nucleic acid synthesis first and to the greatest extent. It was without observable effect on the host red cell. Cordycepin was therapeutically active at doses of 50 mg./kg. and above against blood-induced P. b. berghei infections. Complete cure was not obtained even at the highest doses and toxic effects were observed at doses of 200 mg./kg. and above.