Antimalarial activity in vitro of the glyoxalase I inhibitor diester, S-p-bromobenzylglutathione diethyl ester.

S-p-Bromobenzylglutathione diethyl ester induced toxicity in the malarial parasite Plasmodium falciparum in infected human red blood cells in culture. The median inhibitory concentration, IC50, was 4.77 +/- 0.12 microM (N = 10) for incorporation of [3H]hypoxanthine in nucleotide synthesis and 5.20 +/- 0.1 microM (N = 10) for incorporation of [14C]isoleucine into protein. The prospective mechanism of action is inhibition of glyoxalase I by the de-esterified metabolite, S-p-bromobenzylglutathione, and accumulation of the cytotoxic substrate methylglyoxal.