Phenolic antioxidants-functionalized quaternized chitosan: Synthesis and antioxidant properties

In this work, two kinds of phenolic antioxidants-functionalized quaternized chitosan were synthesized in order to develop aqueous soluble antioxidant–polymer conjugates. Quaternized chitosan conjugated with gallic acid or caffeic acid was carried out and the antioxidant properties of the products (namely gallic acid-quaternized chitosan and caffeic acid-quaternized chitosan) against hydroxyl-radical, superoxide-radical and DPPH-radical were evaluated in vitro, respectively. The scavenging activities of the obtained gallic acid-quaternized chitosan and caffeic acid-quaternized chitosan exhibit a remarkable improvement over those of either chitosan or quaternized chitosan. And the scavenging effect indices of the products were all higher than 90% at a concentration of 1000 μg/mL. Because gallic acid-quaternized chitosan and caffeic acid-quaternized chitosan are convenient to prepare and possess improved potential activities, these materials may represent an attractive new platform for utilizations of chitosan.