Antimicrobial and Antioxidant Activities of N -2-Hydroxypropyltrimethyl Ammonium Chitosan Derivatives Bearing Amino Acid Schiff Bases.

N -2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC), a cationic quaternary ammonium salt polymer exhibiting good solubility in water, is widely used because of its low toxicity and good biocompatibility. Herein, through ion exchange reaction, we prepared N -2-hydroxypropyltrimethyl ammonium chitosan derivatives bearing amino acid Schiff bases with good biological activities. The accuracy of the structures was verified by FT-IR and 1 H NMR. The antibacterial activity, antifungal activity, and scavenging ability of DPPH radical and superoxide radical of HACC derivatives were significantly improved compared with that of HACC. In particular, HACGM (HACC-potassium 2-((2-hydroxy-3-methoxybenzylidene)amino)acetate) and HACGB (HACC-potassium 2-((5-bromo-2-hydroxybenzylidene)amino)acetate) showed good inhibitory effect on bacteria and fungi, including Staphylococcus aureus , Escherichia coli , Botrytis cinerea, and Fusarium oxysporum f. sp. cubense . The inhibition rate of HACGB on Staphylococcus aureus and Escherichia coli could reach 100% at the concentration of 0.1 mg/mL, and the inhibition rate of HACGM and HACGB on Botrytis cinerea and Fusarium oxysporum f. sp. cubense could also reach 100% at the concentration of 0.5 mg/mL. Improving antimicrobial and antioxidant activities of HACC could provide ideas and experiences for the development and utilization of chitosan derivatives.