Figure 5.

Screening of in vitro Plasmodium falciparum blood cultures under various conditions for thioethers (m/z 88+90). Thioethers were absent in the control (A) and in the headspace of 100 mL of a red blood cell suspension (1% hematocrit; B). Thioethers were neither present following treatment with 1000 ng/mL of the antimalarial piperaquine tetraphosphate tetrahydrate (C) nor after treatment-lysing of cells (D). As a positive control, red blood cell cultures were spiked at the levels previously detected in healthy individuals (E). Peaks: 1, allyl methyl sulfide; 2, 1-methylthio-propane; 3, (E)-1-methylthio-1-propene; and 4, (Z)-1-methylthio-1-propene. Data are representative of findings obtained in 2 independent experiments with average parasitemia levels of 29.9%. Abbreviation: VOC, volatile organic compounds.