ascorbic-acid and piperidine

In this study, 3,4,5-trisubstituted piperidines were synthesized enantioselectively, and their antioxidant activity was evaluated. The 3,4,5-trisubstituted piperidines containing TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) and a spatially proximal hydroxy group showed good antioxidant activity. Some of these compounds showed IC50 values in a nanomolar range, comparable to that of TEMPO. Probably the TEMPO generated from the homolysis of the CON bond of 3,4,5-trisubstituted piperidines functions as a radical-scavenging entity, and the hydroxy group of piperidines has a synergistic effect to the antioxidant activity.

Topics: Antioxidants; Dose-Response Relationship, Drug; Molecular Structure; Piperidines; Stereoisomerism; Structure-Activity Relationship

A series of piperamide derivatives (8a-j) was synthesized with various substituted piperidine and piperazine compounds. The prepared compounds were evaluated for antibacterial activity against gram-positive and gram-negative bacteria and antifungal activity by disc diffusion method. The antioxidant activity of the compounds was evaluated by DPPH and superoxide radical scavenging method and antidepressant activity using forced swim and tail suspension behavioral despair tests in mice. The compounds 8a, 8b and 8c were investigated for their monoamine oxidase A and B (MAO-A and MAO-B) inhibitory property. Some of the test compounds were active in forced swim test (FST) and tail suspension test (TST). Compounds 8a and 8b showed a significant effect, when compared to standard drug, clorgyline.

Topics: Amides; Animals; Anti-Bacterial Agents; Antidepressive Agents; Antifungal Agents; Antioxidants; Behavior, Animal; Candida albicans; Gram-Negative Bacteria; Gram-Positive Bacteria; Mice; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Piperazine; Piperazines; Piperidines

We have synthesized several nitroxides with different substituents which vary the steric and electronic environment around the N-O moiety and have systematically investigated the role of substituents on the stability of the radicals. Our results demonstrated the reactivity toward ascorbate correlates with the redox potential of the derivatives. Furthermore, ab initio calculations also indicated a correlation between the reduction rate and the computed singly occupied molecular orbital-lowest unoccupied molecular orbital energy gap, but not with solvent accessible surface area of the N-O moiety, supporting the experimental results and suggesting that the electronic factors largely determine the radicals' stability. Hence, it is possible to perform virtual screening of nitroxides to optimize their stability, which can help to rationally design novel nitroxides for their potential use in vivo.

Topics: Ascorbic Acid; Cyclic N-Oxides; Electron Spin Resonance Spectroscopy; Magnetic Resonance Spectroscopy; Piperidines; Structure-Activity Relationship