Effects of Konjac Glucomannan and Inulin Oligosaccharide on the Colonic Mucosa Barrier, Antioxidant Enzyme Gene Expression and Gut‐associated Lymphoid Tissue Immunity in Mice

Abstract

Konjac glucomannan (KGM) and inulin fructo‐oligosaccharide (mean degree of polymerization=8) effectively protect the AOM‐induced DNA damage in the colonocytes which may reduce the colonic tumorigenesis. The aim of this study was to determine how these fibers modulate mucosa barrier function and immunity that could also contributes to the anti‐carcinogenic potential. Six‐week‐old C57BL/6J mice were randomly assigned to the following diet: control AIN‐93 diet (control group) or that supplemented with 2% (w/w) KGM (KGM group) or inulin (Inulin group) for 21 days. After 12‐h fasting, mice were sacrificed and the plasma and colon were collected. Results indicated that the mucosa barriers were intact in all groups. However, inulin group was characteristics of mucin‐rich crypts and longer crypt length compared with the control group. The gene expression of ZO1, a tight junction protein, was enhanced both in the KGM and inulin groups. The gene expressions of colonic TNF‐α and IL‐10 were increased with KGM and inulin, respectively. The inulin supplementation also significantly increased the plasma TNF‐α level compared with the control group, but not the IL‐10 level. In addition, both KGM and inulin increased the gene expression of glutathione transferase pi and glutathione peroxidase. In summary, our study suggested that both konjac glucomannan polysaccharide and inulin oligosaccharide enhanced the mucosa barrier and antioxidant machinery and modulated the gut‐associated lymphoid tissue immunity. This study was supported by the National Science Council Grant MOST‐103‐2320‐B‐040‐013‐MY3, Taipei, Taiwan.