Article pubs.acs.org/JAFC
Study on Dendrobium officinale O‑Acetyl-glucomannan (Dendronan). 7. Improving Effects on Colonic Health of Mice Guan-ya Zhang,† Shao-ping Nie,*,† Xiao-jun Huang,† Jie-lun Hu,† Steve W. Cui,*,†,§ Ming-yong Xie,† and Glyn O. Phillips# †
State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, People’s Republic of China Guelph Food Research Centre, Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, Ontario N1G 5C9, Canada # Glyn O. Phillips Hydrocolloid Research Centre, Glyndŵ r University, Wrexham LL11 2AW, United Kingdom Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on September 15, 2015 | http://pubs.acs.org Publication Date (Web): September 15, 2015 | doi: 10.1021/acs.jafc.5b03117
§
ABSTRACT: This research was aimed to study the effect of Dendrobium officinale polysaccharide (Dendronan) on colonic health. Mice were fed Dendronan at doses of 40, 80, and 160 mg/kg body weight for 0, 10, 20, and 30 days, respectively. Results showed that Dendronan, which has a special structure formed by mannose and glucose, rich in O-acetyl groups, exhibited improving effects on colonic and fecal parameters of Balb/c mice. After Dendronan feeding, the content of short-chain fatty acids (SCFAs), colon length and index, and fecal moisture were increased, whereas colonic pH was decreased and defecation time was shortened. All of these changes were significantly different between polysaccharide-treated groups and the control group (p < 0.05). These findings suggested that an adequate intake of Dendronan is beneficial to the process of fermentation and regulation of colonic microenvironment, thus playing a role in the maintenance of colonic health. KEYWORDS: Dendrobium officinale O-acetyl-glucomannan, short-chain fatty acids, fecal moisture, defecation time, colonic health
■
INTRODUCTION The function of the colon is to absorb moisture, salt, and vitamins before putting out chyme and to provide an anaerobic environment for chyme fermentation by gut microbes.1,2 Colonic health is closely related to human health and always regarded as a popular research interest in immunology and metabolomics.3 The main factors that affect colonic health include short-chain fatty acids (SCFAs), moisture content of the colon, colonic pH, and the amount of harmful substances in the colon.4−6 In vivo microenvironment, SCFAs are not only the main carbon fuel for microbiota,7 but also can provide energy for colonic epithelial cells (>70%).8 Furthermore, SCFAs have obvious enteroendocrine regulating functions, colon regulating functions, and control of glucose.9−11 Research also showed SCFAs are beneficial to the mitigation of diseases such as colon cancer and cardiovascular disease.12 Colonic moisture contributes to dissolving organic acids, fecal mucins, and immune factors to ensure the maintenance of immune homeostasis.13 Colonic pH is an important parameter to assess the intestinal growth environment and can describe changes in fermentation indices quantitatively.14 Research showed it is favorable to the growth of beneficial microorganism and butyrate-producing bacteria when colonic pH was
