Design, synthesis and anti-oxidant activities of novel 1,2,3,4-tetrazine, 1,2,3-triazoles and coumarin derivatives and their nanoparticular encapsulation

Abstract

Nitrogen-containing heterocyclic compounds are currently used for a number of pharmaceutical and agricultural applications because they have biological activities such as antimicrobial, antiviral, antituberculosis, anticancer, analgesic, antioxidant, anti-inflammatory and antidepressant. 1,2,3,4-Tetrazines and 1,2,3-triazoles are examples of high-nitrogen heterocyclic compounds. Coumarins, on the other hand, are lactones that form a group of oxygenated heterocyclic compounds found in plants. In this article, two analogs of 1,2,3,4-tetrazine, two analogs of 1,2,3-triazole and five analogs of coumarin were designed and synthesized. Their chemical structures were characterized by detecting their FTIR, 1H-NMR, and 13C-NMR (APT) spectra. 
The antioxidant activities of all synthesized molecules were compared at a fixed concentration (0.25 mg/mL) using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. Molecules 9c and 9e, which showed the highest antioxidant activity, were loaded into PLGA (poly(lactic-co-glycolic) acid) nanoparticles using the oil in water (o/w) single emulsion solvent evaporation method as a model study. Synthesized nanoparticles characterized for particle size, zeta potential, functional groups, morphology, and release properties. Particle size and zeta potential of 9c/NP were determined as 216.1±8.944 nm and -14.1±2.40 mV, respectively. The particle size and zeta potential for 9e/NP were measured as 222.0±12.490 nm and -12.4±1.42 mV respectively. The study results obtained on model nanoparticle systems with elucidated physicochemical properties may have the potential to provide a promising basis for oxidative stress-related diseases in the future.