Figure 4

Effect of transient treatment with MA at different plasmodial stages. A. Development of parasitaemia after maslinic acid treatment at different growth stages of P. falciparum 3D7. Twelve-hours ring-stage synchronized cultures at 10% parasitaemia were incubated in the presence of MA 100 μM for 12 hours at times corresponding to ring (R+MA), trophozoite (T+MA) and schizont (S+MA) stages. After treatment, MA was removed and parasitaemia was monitored up to 86 h after culture synchronization: untreated (white triangles), R+MA (white circles), T+MA (black circles), S+MA (black triangles), not-removed MA (black squares). Cycle time indicates the elapsed hours of the culture started with synchronized 12 hour-old rings. Results are presented as arithmetic mean of three independent experiments ± SD. B. Morphological changes observed in the transiently-treated cultures. Representative light-microscopy fields of cultures subjected to the treatment are shown after Wright's-staining at the times indicated.