The Preparation Of Oligochitosan And New Derivatives Of Oligochitosan And Study The Anti-cancer Activity

Chitosan is a kind of natural polysaccharide, which is reproducible and it has non-toxicity, good biocompatibility and biodegradability; it has many bioactivities. Because of its high molecular weight, it has poor-solubility which limited its use. The preparation methods and applications of oligochitosan which has good-solubility have received considerable interests. In this paper, we study the technic condition of the enzyme method and the chemical method in detail. And we compared the products prepared by this two method. And found that the amino contents of the products prepared by chemical method were lower than that of the material. The amino contents of the products prepared by enzyme method almost had no change. Through the study, we found that it could reduce the viscosity of the depolymerization product when added Vc into the depolymerization system. And then we research the enzyme-depolymerziation by several enzymes. It could get oligochitosan whose molecular weight is about 1800 by using three enzymes. And the product yield is also high.Three new kinds of oligochitosan derivatives, clycocyamine derivative of oligochitosan, nicotinoyl derivative of oligochitosan, nicotinoyl isothiocyanates derivative of oligochitosan, were obtained.The inhibition effects of the derivatives on BEL?7402 of liver cancer were studied. The results showed that nicotinoyl derivative of oligochitosan had a better anti-cancer activity than that of other two derivatives and the oligochitosan (inhibitory ratio is 21.54% at 1mg/mL). It has anti-cancer activity at low concentration (inhibitory ratio is 3.57% at 50ug/mL). And the anti-cancer activity depended on derivative concentration. The clycocyamine derivative and nicotinoyl isothiocyanates derivative had no anti-cancer activity at low concentration. But at high concentration, they also had anti-cancer activity.