IN-VITRO EFFECTS OF ARTEMISININ ETHER, CYCLOGUANIL HYDROCHLORIDE (ALONE AND IN COMBINATION WITH SULFADIAZINE), QUININE SULFATE, MEFLOQUINE, PRIMAQUINE PHOSPHATE, TRIFLUOPERAZINE HYDROCHLORIDE, AND VERAPAMIL ON TOXOPLASMA-GONDII

The in vitro effects of the following antimicrobial agents on Toxoplasma gondii tachyzoites were studied: artemisinin ether (arteether), cycloguanil hydrochloride (cycloguanil), mefloquine, primaquine phosphate, and quinine sulfate, as well as the calcium channel blocker verapamil and the calmodulin inhibitor trifluoperazine hydrochloride. Arteether at greater than or equal to 0.5 mu g/ml and cycloguanil at greater than or equal to 1.0 mu g/ml inhibited T. gondii in vitro. Cycloguanil (2.5 mu g/ml) combined with a noninhibitory concentration of sulfadiazine (25 mu g/ml) inhibited T. gondii more than cycloguanil alone. Neither primaquine phosphate, mefloquine, nor quinine sulfate had an inhibitory effect on intracellular T. gondii. Verapamil and trifluoperazine hydrochloride were not inhibitory at lower physiologic concentrations, but higher physiologic concentrations were toxic to cell cultures in vitro and therefore our assay could not be used to assess their effects.