Structure of N-gamma-L-glutamyl-L-cysteine ethyl ester monohydrate

Novel inhibitory effects of gamma-glutamylcysteine ethyl ester against human immunodeficiency virus type 1 production and propagation

The anti-human immunodeficiency virus type I (anti-HIV-1) effects of gamma-glutamylcysteine ethyl ester (gamma-GCE; TEI-2306) were examined in vitro. In initial studies using a vigorously HIV-1-producing human T-lymphocytic cell line, gamma-GCE displayed a novel biphasic repressive effect on chronic HIV-1 infection that was unlike that of other glutathione prodrugs or other reported antioxidants. In high doses, up to a concentration of 2.5 mM, at which neither glutathione (GSH) nor another GSH precursor has shown inhibitory effects, gamma-GCE potently inhibited the production of HIV-1 by a selective cytopathic effect against infected cells, while the viability and growth of uninfected cells were unaffected at the same gamma-GCE concentrations. At lower concentrations (200 to 400 microM), gamma-GCE significantly repressed the virus production from chronically HIV-1-expressing cells without affecting their viability. The discrepancy of the thresholds of the toxic doses between infected and uninfected cells was found to be more than 10-fold. Relatively high doses of gamma-GCE, utilized in acute HIV-1 infection of T-lymphocytic cells, entirely blocked the propagation of HIV-1 and rescued the cells from HIV-1-induced cell death. Furthermore, gamma-GCE at such concentrations was found to directly inhibit the infectivity of HIV-1 within 4 h. Repressive effects of gamma-GCE on acute HIV-1 infection in human primary human peripheral blood mononuclear cells were also demonstrated. Here, the anti-HIV-1 strategy utilizing gamma-GCE is removal of both HIV-1-producing cells and free infectious HIV-1 in vitro, in place of specific immunoclearance in vivo, which might lead to an arrest or slowing of viral propagation in HIV-1-infected individuals.

The cardioprotective effect of gamma-glutamylcysteine ethyl ester during coronary reperfusion in canine hearts

1. The cardioprotective effect of gamma-glutamylcysteine ethyl ester was investigated on ischaemia-reperfusion-induced myocardial damage in anaesthetized dogs. 2. Open chest anaesthetized dogs were divided into four groups: 2 h occlusion of the left anterior descending coronary artery (LAD); 2 h LAD occlusion followed by 1 h reperfusion; 2 h LAD occlusion followed by 1 h reperfusion with administration of gamma-glutamylcysteine ethyl ester (10 mg kg-1 just before reperfusion); 2 h LAD occlusion followed by 1 h reperfusion with administration of GSH (the reduced form of glutathione, 10 mg kg-1 just before reperfusion). 3. After occlusion or reperfusion, heart mitochondria were prepared from the normal area and the occluded or the reperfused area, and mitochondrial function (rate of oxygen consumption in State III, and respiratory control index) was measured polarographically. 4. Mitochondrial GSH and GSSG (the oxidized form of glutathione) concentrations, and activities of glutathione peroxidase and glutathione reductase were measured. 5. Two h of LAD occlusion induced mitochondrial dysfunction with depletion of mitochondrial GSH concentration. One h of reperfusion after 2 h LAD occlusion induced significant mitochondrial dysfunction associated with a marked depletion of mitochondrial GSH concentration. 6. gamma-Glutamylcysteine ethyl ester reduced mitochondrial dysfunction and depletion of mitochondrial GSH concentration after 2 h LAD occlusion and 1 h reperfusion. In contrast, GSH did not prevent depletion of mitochondrial GSH concentration and mitochondrial dysfunction after 2 h LAD occlusion followed by 1 h reperfusion. 7. The activities of glutathione peroxidase and glutathione reductase did not change significantly in each group. 8. One h of reperfusion after 2 h occlusion of LAD induced ventricular arrhythmias. gamma-Glutamylcysteine ethyl ester markedly reduced the development of reperfusion arrhythmias, whilst GSH showed no protective effect.9. Gamma-Glutamylcysteine ethyl ester maintained mitochondrial GSH concentration, prevented reperfusion myocardial damage, and reduced reperfusion arrhythmias.