Assessment of antioxidant and DPPH free radical scavenging activity of 1,2-dithiole-3-thione derivatives by using cyclic voltammetry, spectroscopic, and molecular docking studies

The antioxidant and the DPPH free radical scavenging activity of 4-phenyl-3H-1,2-dithiole-3-thione (DT1), 5-(4-fluorophenyl)-3H-1,2-dithiole-3-thione (DT2), 5-(4-phenyl-3-thioxo-3H-1,2-dithiol-5-yl)benzo[d]oxazole-2(3H)-thione (DT3) and 4-methyl-5-((phenylamino) methyl)-3H-1,2-dithiole-3-thione (DT4) was investigated using cyclic voltammetry (CV) and electronic spectroscopy (ES) assays. The diminution in anodic peak current density of an acetonitrile solution of DPPH in the absence and presence of gradually increasing amounts of 1,2-dithiole-3-thione derivatives (DT) was successfully exploited for measuring the antioxidant activity and the DPPH free radical scavenging activity. The EC50 values obtained from the CV and ES experiments suggested that all compounds had potential DPPH radical scavenging ability with the derivative DT3 possessing the highest potency of 21.5 +/- 1.30 from CV and 20.6 +/- 1.05 from ES. A molecular docking simulation indicated that all DT derivatives interacted with amino acid residues of glutathione reductase via hydrogen bonding and hydrophobic interactions. Based on the inhibitory concentration and docking score values, compound DT4 was the second inactive compound against the glutathione reductase enzyme having values equal to 41.4 mu M and a docking score of -25.6 kJ/mol respectively. Toxicity perdition studies revealed that compounds DT1 and DT2 were non-toxic. [GRAPHICS] .