Investigation of Inhibition Effect of Nitro Group Containing Substances on Glutathione Reductase Enzyme

Glutathione reductase (Glutathione: NADP+ oxidoreductase, EC 1.8.1.7; GR) catalyzes electron transfer between reduced (GSH) or high molecular weight (GSSG) disulfide substrates and reduced pyridine nucleotides (NADPH). Discovery of glutathione reductase (GR) inhibitors has become very popular recently due to antimalarial and anticancer activities. Enzymatic activity was measured by Beutler’s method with a Spectrophotometer, at 25°C. The assay system contained 100 mM Tris-HCl buffer pH 8.0, including 0.5 mM EDTA, 3.3 mM GSSG and 0.1 mM NADPH. Inhibition effects of Nitrobenzene (1), 3,5- Dinitrosalicylic acid (2), (2,4-Dinitrophenyl)((4-(prop1-en-2-yl)cyclohex-1-enyl)-methyl)sulfane (3), ((7,7- dimethylbicyclo[2.2.1]heptan-1-yl)methyl)-(2,4- dinitrophenyl)sulfane (4), and ((2-Chloro-7,7- dimethylbicyclo[2.2.1]heptan-1-yl)methyl)-(2,4- dinitrophenyl)sulfane (5) compounds on GR have been investigated in vitro. IC50 values were determined by drawing % activity- [I] graphs for compounds showing inhibition effects. IC50 values of GR for these substances were observed to be at micromolar level.