Preventive effects of chlorophyllin fixed on chitosan towards DNA adduct formation of 3-amino-1-methyl-5H-pyrido (4,3-b)indole in CDF1 mice.

摘要

Chlorophyllin, a water-soluble derivative of chlorophyll, is known to suppress the mutagenic and carcinogenic action of compounds having polycyclic structures, e.g., heterocyclic amines and aflatoxin B1. Recently, we reported that chlorophyllin fixed on chitosan (chl-chitosan), which is insoluble in water, can efficiently and tightly trap these heterocyclic amines. We have studied whether this adsorption to chl-chitosan can result in an interference with DNA-adduct formation caused by 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), a heterocyclic amine, in CDF1 mice, in which Trp-P-2 had been shown to induce hepatocellular carcinomas. Mice were fed a diet containing Trp-P-2 with or without chl-chitosan. After 3 d of feeding, DNA-adduct formation in liver and lung was examined by 32P-postlabeling analysis. Adducts formed from Trp-P-2 were significantly decreased by the chl-chitosan addition (p<0.05, t-test). These results suggest that the uptake of Trp-P-2 into the mouse was lowered by its adsorptionto chl-chitosan, either within the digestive tract or within the food itself. This trapping agent, chl-chitosan, is thus worthy of study for cancer chemoprevention.