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.