Synthesis, characterization and antioxidant activity of chitosan-chromone derivatives

In this study, a new chromone-functionalized chitosan Schiff base and its cross-linked derivative were synthesized and characterized by FT-IR, UV-vis, C-13 CP/MAS solid-state NMR, TGA, XRD-powder and SEM measurements and elemental analysis data. Degrees of substitution (DS) were determined from the elemental analysis by using the C/N ratios. The in vitro antioxidant activity of high molecular chitosan and its chromone derivatives was evaluated as radical scavengers against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH%). The results showed that both of the chitosan-chromone derivatives have good antioxidant potential which might be due to the phenolic group introduced after chemical modification of chitosan with a chromone derivative. Chromone-chitosan Schiff base (CSCH) had a better ability to scavenging DPPH radical (IC50, 0.88 mg/mL) than that of its cross-linked derivative (CSCH-TP) obtained by using terephthalaldehyde (IC50, 1.32 mg/mL).