The physicochemical properties and antitumor activity of cellulase-treated chitosan

Cellulase was used to partially hydrolyse N-acetylated chitosan. The hydrolysis process was monitored by gel permeation chromatography. Factors affecting the enzymatic hydrolysis of chitosan were studied. The degraded chitosans were characterized by X-ray diffraction, thermogravimetric analysis, differential thermal analysis, Fourier transform infrared and carbon-13 magnetic resonance spectra. The results showed that the enzymatic hydrolysis was by endo-action, and the total acetylation degree of chitosan did not change after degradation. The decrease of molecular weight led to transformation of crystal structure, alteration of thermostability and increase of water-solubility, but the chemical structures of residues were not modified. Most reducing end-residues of produced oligomers were GlcNAc units. This water-soluble product inhibited the growth of sarcoma180 tumor cells in mice with maximum inhibitory rates of 50% by intraperitoneal injection and 31% by oral administration.