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 -NH(2) 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((C=O))), 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.