ABSTRACT
PURPOSE: Two types of chitosan oligosaccharides (COSs), COS I and COS II, were investigated for the effects on ascitic tumor and enzymes for cancer chemoprevention. MATERIALS AND METHODS: Chitosan oligosaccharides were administered once daily for 10 days after the tumor implantation. The change of body weight was observed for 20 days, and the survival rate of mice was determined after 21 days. Chitosan oligosaccharides were administered once daily for 10 days before the tumor implantation (1 106 cells). The number of ascitic tumor cells were measured at 6 days after tumor implantation. Chemopreventive potential of chitosan oligosaccharides was examined by the induction of quinone reductase and inhibition of cytochrome P450 1A1. RESULTS: Chitosan oligosaccharides exerted antitumor activity by inhibiting the growth of Ehrlich ascites tumor cells in vivo. Mice given Ehrlich cells and 10 or 100 mg/kg body weight of chitosan oligosaccharides had 33% survival after 21 days. Quinone reductase activity was increased with chitosan oligosaccharides. There were 26% and 33% inhibition in the activity of cytochrome P450 1A1 enzyme with the treatment of COS I and COS II, respectively. CONCLUSION: These results suggest that chitosan oligosaccharides has antitumor activity and cancer chemo preventive potential by inducing QR activity and inhibiting cytochrome P450 1A1.