Preparation of chitosan derivatives containing aromatic five-membered heterocycles for efficient antimicrobial and antioxidant activities

In this study, nine chitosan derivatives containing aromatic five-membered heterocycles were prepared and the effects of different grafting methods on the biological activities of chitosan derivatives were investigated. The structures of all the compounds were characterized by Fourier Transform Infrared (FT-IR) spectroscopy and Nuclear Magnetic Resonance (NMR) spectroscopy, while the antioxidant, antifungal and antibacterial activities of the chitosan derivatives were tested. The experimental data suggested that the chitosan derivatives had outstanding inhibitory ability against Fusarium graminearum, Fusarium oxysporum f.sp.cucumbrum, Staphylococcus aureus and Escherichia coli. At the same time, some of the compounds showed strong scavenging ability against DPPH radical and superoxide radical. Cytotoxicity experiments have demonstrated that some chitosan derivatives are non-toxic to L929 cells. More importantly, compared to chitosan, these chitosan derivatives have good water solubility and can be used as potential polymers for antifungal and antibacterial biomaterials in agriculture.