Hydroxyl containing seleno-imine compound exhibits improved anti-oxidant potential and does not inhibit thiol-containing enzymes

Design and synthesis of organoselenium compounds with high thiol peroxidase (TPx) and low thiol oxidase (TOx) activities have been a difficult task and remains a synthetic-activity relationship dilemma. In this regard we are reporting for the first time a detail experimental data (both in vitro and in vivo) about the anti-oxidant and toxicological profile of an lmine (-N=) containing organoselenium compound (Compound A). The TPx activity of Compound A was significantly higher than diphenyl diselenide (DPDS). Both Compound A and DPDS protected sodium nitropruside (SNP) induced thiobarbituric acid reactive species (TBARS) production in rats tissue homogenate with significantly higher activity observed for Compound A than DPDS (p < 0.05). The Compound A also exhibited strong antioxidant activity in the DPPH and ABTS radical scavenging assays. This study reveals that an imine group close to selenium atom drastically enhances the catalytic activities in the aromatic thiol (PhSH) assay systems. The oxidation of biologically significant thiols reflects the toxicity of the compounds. However, the present data showed that treatment with Compound A at 0, 10.25 or 50 mg/kg was not associated with mortality or body weight loss. Similarly it did not inhibit alpha-ALA-D and Nat(+1)/K+1 ATPase (sulfhydryl group containing enzymes) activities after acute oral treatment; rather it enhanced non-protein thiols (NPSH) concentration. The Compound A did not cause any oxidative stress as measured by TBARS production in rat's tissue preparation. Our data also indicate that exposure to Compound A did not affect plasma transaminase activities or levels of urea and creatinine in rats. Ascorbic acid is always considered a marker of oxidative stress and the reduction of its content may indicate an increase in oxidative stress. Treatment with Compound A did not alter Ascorbic acid levels in rats. The conducted in vitro and in vivo tests show the versatile therapeutic potential of this compound in the area of free radical induced damages, will undoubtedly enhance our understanding of the mechanism of model compounds and may ultimately yield insights that result in improved GPx mimics. (C) 2011 Elsevier Ireland Ltd. All rights reserved.