Effects of selected quinolin-4(1H)-imines on oxygen consumption of Leishmania parasites. L. infantum axenic amastigote (A) and L. infantum (B), L. amazonensis (C), and L. major (D) promastigotes were treated with 2-fold the IC50s of each selected quinolin-4(1H)-imine. Percentages of inhibition are relative to the oxygen consumption values obtained at basal levels. The graphs show the mean values and standard deviations (error bars) from 3 independent experiments. KCN was used as the positive control. Statistical significance was determined using a paired t test. *, P < 0.05; **, P < 0.005; ***, P < 0.0005; ****, P < 0.0001.