Synthesis and bio-activities of new chitosan Schiff base derivatives with salicylaldoxime and 3-nitro aniline

A new chitosan-based Schiff base derivative of CS-3NA was synthesized by condensing chitosan with salicylaldoxime and 3-nitroaniline. The structural resonances were identified using Fourier transform infrared spectroscopy (FTIR), UV,1H, and 13C NMR analyses. Gas chromatography–mass spectrometry provided evidence for the existence of aromatic fragments associated with the synthesized derivative, whereas high-performance liquid chromatography (HPLC) indicated purity of 93.19% for the extracted molecule. The UV–vis spectrum exhibited absorption bands at 224.85 and 283.55 nm, corresponding to n→π* and imine transitions. Thermogravimetric analysis (TGA) revealed two main degradation stages and thermal stability up to 160 °C. The activation energy of thermal decomposition was calculated using the Arrhenius method (Ea = 179.9 kJ mol−1), indicating enhanced thermal stability compared to native chitosan. In vitro cytotoxicity evaluated using the MTT assay against MCF-7 breast cancer cells showed dose-dependent inhibition, with an IC50 value of 76.03 µg mL−1 after 24 h incubation. The results demonstrate that the structural modification of chitosan with salicylaldoxime and 3-nitroaniline produces a derivative with improved physicochemical properties and promising biological activity.