In vitro inhibition of Toxoplasma gondii by the anti-malarial candidate, 6-(1,2,6,7-tetraoxaspiro[7.11]nonadec-4-yl)hexan-1-ol.

An anti-malarial candidate, 6-(1,2,6,7-tetraoxaspiro[7.11]nonadec-4-yl)hexan-1-ol (N-251), was studied to characterize its potential as a novel anti-Toxoplasma gondii drug. In the present study, IC50 and LC50 of N-251 on host cells and T. gondii were compared to those of artemisinin and sulfadiazine. The IC50 on Huh-7 cells was 10.19μg/ml, 67.69μg/ml and 310.17μg/ml for N-251, artemisinin, and sulfadiazine, respectively. The LC50 for anti-T. gondii effect was shown to be 1.11μg/ml, 5.79μg/ml, and 5.45μg/ml for N-251, artemisinin and sulfadiazine, respectively. N-251 concentration causing complete parasiticidal effect with minimal cytotoxicity on host cells was determined to be 5μg/ml. Additionally, the anti-T. gondii effect of N-251 was confirmed by ultrastructural changes, loss of organelles, degenerated morphology and the increase of amylopectin as detected by transmission electron microscope (TEM). Accordingly, the present study suggests that the anti-malarial synthetic endoperoxide, N-251, is an emerging drug candidate more effective than artemisinin and sulfadiazine.