FIG. 4.

Stage-specific antimalarial effect of HDTAB. P. falciparum culture was synchronized using 5% d-sorbitol, and parasitemia was adjusted to 0.5 to 0.7% at a hematocrit level of 1% with fresh and uninfected B⁺ human RBCs. Incorporated [³H]hypoxanthine was determined as described in Materials and Methods. [³H]hypoxanthine incorporation in ring (A), trophozoite (B), and schizont (C) stages of P. falciparum is presented as counts per minute. (D) Growth inhibitory effect of HDTAB toward rings, trophozoites, and schizonts. Incorporation of [³H]hypoxanthine in HDTAB-treated cells was measured and compared to the value in the DMSO control, which was taken as 100% growth or 0% growth inhibition. Data are presented as means ± standard errors of the means (error bars) for three different experiments performed in triplicate.