Synthesis of N-furoyl chitosan and chito-oligosaccharides and evaluation of their antioxidant activity in vitro

N-furoyl chitosan (NF-CS) and N-furoyl chitosan oligosaccharide (NF-COS) were prepared via acylation of chitosan and chitosan oligosaccharide. Their chemical structures and physical properties were characterized by Fourier transform infrared spectroscopy, 1H NMR, X-ray diffraction, and elemental analysis. Results showed that the degrees of substitution of the derivatives were 0.68 and 0.72, respectively. Their antioxidant activities in vitro were further studied. The inhibition concentration of NF-CS at 50% (IC50) and the scavenging effect of NF-COS on DPPH were 1.3 and 0.76 mg mL−1, respectively. The derivatives also exhibited higher antioxidant activities than chitosan based on the reducing power and hydroxyl radical scavenging activities.