Inhibition of cell proliferation in culture. The EC50 values for L. major promastigote proliferation were determined for dipyridamole (panel A), etazolate (panel B) and trequinsin (panel C). Panel D represents an EC50 determination for trequinsin with L. infantum amastigotes. EC50 values were determined various time points and cell densities, and all growth experiments were repeated at least three times. Representative growth curves for each inhibitor are shown. EC50 values for all inhibitors were in the 30 – 100 μM range for both promastigotes and amastigotes.