EFFECTS OF APPLE PECTIN ON FECAL BACTERIAL ENZYMES IN AZOXYMETHANE-INDUCED RAT COLON CARCINOGENESIS

Because of the potential significance of colonic bacteria in colon car cinogenesis, we investigated the effect of pectin of different types o n fecal bacterial enzymes (beta-glucuronidase, beta-glucosidase and tr yptophanase) at various periods of time after feeding rats with pectin -containing diets during azoxymethane-induced colon carcinogenesis. Th e diet supplemented with 20% apple pectin or 20% citrus pectin decreas ed the multiplicity of colon tumors, and the number of tumors was sign ificantly decreased in the group fed apple pectin. The incidence of co lon tumors in the apple pectin group was lower than that in the contro l group. The mean tumor size was similar among the three groups. Apple pectin feeding decreased fecal beta-glucosidase and tryptophanase lev els. Furthermore, a significant decrease in the activity of beta-glucu ronidase was observed in the apple pectin group during the initiation phase. These findings suggest that the protective effect of pectin on colon carcinogenesis may be dependent on the type of pectin and be rel ated to the decrease of beta-glucuronidase activity in the initiation stage of carcinogenesis.