Ultrastructure of Plasmodium falciparum "in vitro". II. Morphological patterns of different quinolines effects.

In the present morphological study, we used electron microscopy (EM) to evaluate the activity of three quinolines upon Plasmodium falciparum strains cultured in vitro. The drugs (namely chloroquine, mefloquine and a new active substance, SF6606) showed common cellular targets (i.e. feeding process, protein synthesis, membrane formation and utilisation) but gave rise to different morphological features. EM as a tool is able to reveal a variety of drug-induced alterations, but it does not seem to supply evidence of a definite mechanism of action. Nevertheless, our observations suggest that each drug acts via several mechanisms, possibly linked to different degrees of parasite susceptibility.