Structural features and bioactivities of the chitosan

Fourier transform infrared (FT-IR) spectroscopic studies (3500-600 cm−1) showed some different bands of chitosan. The absorption at 3439 cm−1 is stretching vibration of -OH and -NH2 bonds, indicating the association of the hydrogen-bond between them. The bands at 1659, 1599 and 1321 cm−1 are attributable to the peaks of stretching vibrations of amide I (ν(CO)), II (δ(N-H)), and the peak of stretching and bending vibrations of III (ν(C-N)) (δ(N-H)). The chitosan showed strong free radical scavenging activities. Pretreatment with chitosan significantly prevented the decrease of antioxidant enzymes activities and the increase of p-JNK at 3 h after renal ischemia and reduced renal tubular epithelial cell apoptosis.