Synthesis, Characterization, Antioxidant Activity, Antibacterial Activity, and Cytotoxicity of Quaternized Inulin Derivatives Bearing Aromatic Amides.

In this study, a total of 12 new quaternized inulin (QIL) derivatives bearing aromatic amides were synthesized according to the ion exchange method. All the derivatives exhibited higher antioxidant activities in scavenging hydroxyl radicals, DPPH radicals, and superoxide radicals compared to pure inulin. Most of the derivatives could fully eliminate hydroxyl radicals at 1.6 mg/mL. Meanwhile, QIL derivatives exhibited increased antibacterial activity against Escherichia coli and Staphylococcus aureus compared to unmodified inulin. The structure-function relationship of the synthesized derivatives was discussed. Moreover, assays conducted with L929 cells (mouse fibroblasts) by the cell counting kit-8 (CCK-8) method did not show toxicities for the derivatives. Thus, the derivatives show promise for biomedical materials, functional foods, and pharmaceutical applications because they combine excellent antioxidant and antibacterial activities without exhibiting cytotoxicity.