TABLE 2.

Comparative toxicities of cysteine derivatives against P. falciparum versus normal cells^a

^aR¹, acid group side chain; R², amine group side chain; X, atom or group on compound shown in Fig. 1.

^bSelectivity index was calculated as the difference between P. falciparum and mammalian cells (neonatal foreskin fibroblast cell toxicity IC₅₀ values/IC₅₀ of P. falciparum).