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(nu((C=O))), II (delta((N-H))), and the peak of stretching and bending vibrations of III (nu((C-N))) (delta((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. (C) 2011 Elsevier B.V. All rights reserved.