Fig. 9.

Isobolograms describing the interactions of proguanil or tBuPG with cycloguanil and cycloguanil with atovaquone against P. falciparum 3D7 parasites. The interactions of antimalarial compounds was assessed using isobologram analysis in 48 h assays. I values were calculated as previously described⁴. Positive values of I indicate synergism, and negative values indicate antagonism; addition occurs when I equals 0. The significance of the difference of I from zero was assessed with Student’s t test