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Pectin and Its Hydrolysates Stimulate Intestinal Mucin Secretion
Author(s) -
Hino Shingo,
Morita Tatsuya
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.968.2
Subject(s) - pectin , mucin , pectinase , secretion , chemistry , goblet cell , biochemistry , polysaccharide , biology , enzyme , epithelium , genetics
Objectives Soluble dietary fibers (SDF) increase small intestinal mucin secretion by increasing the number of goblet cells in proportion to the viscosity of the SDF ingested. Our recent study showed in rats that low methoxyl pectin (LPC) enhanced mucin secretion irrespective of goblet cell number in the small intestine. Mucin secretory effects of LPC were also confirmed in vitro using HT‐29MTX cells, suggesting that pectin directly stimulates mucin secretion from the individual goblet cells. The present study aimed to characterize the mucin secretory effect of pectin among SDF and to clarify active components of pectin related to mucin secretion. Materials & Methods HT‐29MTX cells were cultured with 6.25–100 mg /L of the respective SDF including pectin for 24 h. The culture media were gathered and subjected to MUC5AC determination. RNA was extracted from the cells and subjected to gene expression analysis for MUC5AC . Pectin hydrolysates were obtained from citrus pectin using pectinase (polygalacturonase) and fractionated by diethylaminoethanol cellulose column. Mucin secretory effects of the hydrolysates were also examined. Results & Findings Only pectin stimulated mucin secretion from HT‐29MTX cells. Mucin secretory effects of pectin were observed irrespective of molecular size, their origins and degree of methoxylation. Pectin hydrolysates also stimulated mucin secretion accompanied by the increase in MUC5AC expression, but oligo‐galacturonic acids did not. The minimal effective concentrations of pectin hydrolysates were 100‐fold lower than those of pectin. Sugar composition analysis showed that pectin hydrolysates contained higher concentrations of rhamnose and neutral sugars compared with the pectin. From these results, it is plausible to assume that hairy region (rhamnogalacturonan carrying side chains) rather than smooth region (homogalacturonan) in the pectin molecule is responsible for mucin secretory effects. Conclusion Among the various SDF tested, only pectin and pectin hydrolysates have exerted significant increases in mucin release from the cells. Clearly, they act as mucin secretagogue.