The effect of anti-malarial drugs on Plasmodium falciparum (New Guinea strains) developing in vitro

Abstract
A method is described which has been used to study the effects of drugs on trophozoites of P. falciparum (New Guinea strains) growing in vitro The effects of sera containing various anti-malarial drugs—paludrine, atebrin, sontochin (SN6911), M4430, resochin (SN7618), plasmoquine, quinine, sulphadiazine and sulphamerazine—on these parasites are described. Atebrin, sontochin, resochin and quinine were observed to cause arrest of development and degeneration of ring and amoeboid forms. Paludrine and M4430 exerted their lethal effect on the early schizonts. The sulphonamides caused degeneration of divided schizonts. Plasmoquine had inconstant or only minor effects. The degenerating forms seen when paludrine is used in vitro with P. falciparum and in vivo with P. vivax are similar. The mode of action of anti-malarial drugs is discussed.