Melarsen oxide

Melarsen oxide (0-150 μM) competitively inhibits purified erythrocyte glutathione reductase, with a K_i value of 23.7 μM, and shows no obvious time-dependent secondary inactivation^[1].
Melarsen oxide inhibits purified Setaria digitata glutathione reductase via a two-stage mechanism, with a K_i of 38.3 μM and a maximum inactivation rate of 1.0×10^-4 s^-1 in the second stage; this inhibitory effect is fully reversible by excess GSSG^[1].
Melarsen oxide (0.5-10 μM; ~30-100 min) induces rapid, dose-dependent lysis of bloodstream-form trypanosomes of T. b. brucei strain 427; complete lysis occurs within 30 min at 10 μM, within 40 min at 2.5 μM, and the lysis rate reaches 50% at approximately 100 min at 0.5 μM^[2].
The EC₅₀ values of melarsen oxide (72 h or 48 h treatment followed by 24 h resazurin incubation) against bloodstream-form T. b. brucei strain 427 in the endpoint propidium iodide assay are comparable to those obtained from the Alamar Blue assay, ranging from ~1.5 nM to ~5 nM depending on the initial seeding density^[2].
Melarsen oxide (up to 100 μg/mL; 70 h) potently inhibits the growth of the bloodstream form strain STIB 900 of Trypanosoma brucei rhodesiense, with an MIC of 6.5 ng/mL^[3].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.