Parasite growth inhibition curve with artesunate concentration for the quantitative test. This curve resulted from the analysis of data sets from nine independent assays using a four-parameter nonlinear regression. Each concentration was tested in triplicate in each independent assay. The X-axis was transformed into logarithm to the base 10 to better visualize the linear portion of the curve. Data are presented as the mean ± SD (n ≥ 9). FU = fluorescence unit; Log₁₀ = logarithm to the base 10; [AS] = artesunate concentration; nM = nanomolar; Red-dotted lines = indicate linearity interval.