New antioxidant agents are urgently required to combat oxidative stress, which is linked to the emergence of serious diseases. In an effort to discover potent antioxidant agents, a novel series of 2-thiouracil-5-sulfonamides (4–9) were designed and synthesized. In line with this approach, our target new compounds were prepared from methyl ketone derivative 3, which was used as a blocking unit for further synthesis of a novel series of chalcone derivatives 4a–d, thiosemicarbazone derivatives 5a–d, pyridine derivatives 6a–d and 7a–d, bromo acetyl derivative 8, and thiazole derivatives 9a–d. All compounds were evaluated as antioxidants against 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2), lipid peroxidation, and 15-lipoxygenase (15-LOX) inhibition activity. Compounds 5c, 6d, 7d, 9b, 9c, and 9d demonstrated significant RSA in all three techniques in comparison with ascorbic acid and 15-LOX inhibitory effectiveness using quercetin as a standard. Molecular docking of compound 9b endorsed its proper binding at the active site pocket of the human 15-LOX which explains its potent antioxidant activity in comparison with standard ascorbic acid.

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Hypothesis:The structural modularity of Gemini Amphiphilic Pseudopeptides (GAPs) allows the tuning of the self-assembling properties by slight modifications in the chemical structures.We hypothesized that the introduction of a flexible linker containing a central nitrogen atom in bipodal and tripodal GAPs would improve their self-assembly properties in aqueous media.Experiments: After preparation of the corresponding GAPs, a combination of SEM, TEM and AFM techniques were used to study the morphology of the self-assembled structures in different media. The solution structures in non-aggregated states were also analyzed by combining NMR, UV and CD studies. The transition from the non-aggregated species to the hierarchical self-assembly was monitored by ATR FT-IR spectroscopy, while the critical aggregation concentration in water was determined by fluorescence spectroscopy. Findings:The formation of different morphologies (vesicles or fibers) highly depends on the polarity and the pH of the medium. A reasonable mechanism for the self-assembly has been established in agreement with the experimental techniques used, where the protonation of the nitrogen in the linker must play a key role. In general, the obtained GAPs showed an improved formation of vesicles in aqueous media (different pH or ionic strength) with potential applications in biomedicine and drug delivery.

A gemini amphiphilic pseudopeptide promotes the spontaneous formation of an oil-in-water emulsion with a high thermal, mechanical and acid-medium stability. The micro-droplets thus formed are disassembled by strong bases or after the action of an enzyme, showing a potential for stimulus-responsive material formulations.

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