title: Fermentation of resistant starches: influence of in vitro models on colon carcinogenesis.
abstract: Resistant starch type 2 (RS2) and type 3 (RS3) containing preparations were digested using a batch (a) and a dynamic in vitro model (b). Furthermore, in vivo obtained indigestible fractions from ileostomy patients were used (c). Subsequently these samples were fermented with human feces with a batch and a dynamic in vitro method. The fermentation supernatants were used to treat CACO2 cells. Cytotoxicity, anti-genotoxicity against hydrogen peroxide (comet assay) and the effect on barrier function measured by trans-epithelial electrical resistance were determined. Dynamically fermented samples led to high cytotoxic activity, probably due to additional compounds added during in vitro fermentation. As a consequence only batch fermented samples were investigated further. Batch fermentation of RS resulted in an anti-genotoxic activity ranging from 9-30% decrease in DNA damage for all the samples, except for RS2-b. It is assumed that the changes in RS2 structures due to dynamic digestion resulted in a different fermentation profile not leading to any anti-genotoxic effect. Additionally, in vitro batch fermentation of RS caused an improvement in integrity across the intestinal barrier by approximately 22% for all the samples. We have demonstrated that batch in vitro fermentation of RS2 and RS3 preparations differently pre-digested are capable of inhibiting the initiation and promotion stage in colon carcinogenesis in vitro.
authors.affiliation: Institute of Food Science and Nutrition, ETH Zurich, Schmelzbergstrasse) Zurich, Switzerland.
authors.forename: Caroline
authors.initials: C
authors.lastname: Fässler
authors.forename: Chris I R
authors.initials: CI
authors.lastname: Gill
authors.forename: Eva
authors.initials: E
authors.lastname: Arrigoni
authors.forename: Ian
authors.initials: I
authors.lastname: Rowland
authors.forename: Renato
authors.initials: R
authors.lastname: Amadò
mesh_terms: D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D018938:Caco-2 Cells; D003110:Colonic Neoplasms / Q000517:prevention & control*; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D004063:Digestion; D005232:Fatty Acids, Volatile / Q000032:analysis / Q000378:metabolism*; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005285:Fermentation; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D013213:Starch / Q000378:metabolism* / Q000494:pharmacology; D013997:Time Factors
chemical_list: D005232:Fatty Acids, Volatile; D013213:Starch; D006861:Hydrogen Peroxide