title: Comparative effects in rats of intact wheat bran and two wheat bran fractions on the disposition of the mutagen 2-amino-3-methylimidazo[4,5-f]quinoline.
abstract: Wheat bran protects against mutations and cancer, but contains different plant cell types that are likely to have different protective effects. We previously described the production and chemical characterisation of an aleurone-rich fraction (ARF) and a pericarp-rich fraction (PRF) from wheat grain. We compared these with whole bran (WB), fed to rats as 10% of a high fat AIN-76 diet. All bran-supplemented diets increased faecal bulk, in the order PRF>WB>ARF. PRF increased the activity of NAD(P)H:quinone acceptor oxidoreductase only in the forestomach, whereas ARF and WB enhanced levels of glutathione S-transferase in the duodenum. ARF but not PRF was digested and fermented, and also encouraged bacterial growth. Rats were gavaged with the radioactive mutagen (14)C-labelled IQ (2-amino-3-methylimidazo[4,5-f]quinoline), and effects of the brans on plasma radioactivity measured. Compared with the control diet, all bran-supplemented diets reduced the concentration of radioactivity in plasma, in the order ARF>PRF>WB. All brans increased faecal elimination of radioactivity, but only ARF and PRF enhanced urinary radioactivity. These data suggest that wheat bran may reduce mutation and cancers through direct adsorption and enhanced elimination of a dietary mutagen and/or its metabolites, and that wheat bran enriched in pericarp or aleurone cell walls may exert protective effects through different mechanisms.
authors.affiliation: The University of Auckland, Auckland, New Zealand. l.ferguson@auckland.ac.nz
authors.forename: Lynnette R
authors.initials: LR
authors.lastname: Ferguson
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Harris
authors.forename: Philip
authors.initials: P
authors.lastname: Kestell
authors.forename: Shuotun
authors.initials: S
authors.lastname: Zhu
authors.forename: Rex
authors.initials: R
authors.lastname: Munday
authors.forename: Christine M
authors.initials: CM
authors.lastname: Munday
mesh_terms: D000818:Animals; D016587:Antimutagenic Agents / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects; D002273:Carcinogens / Q000378:metabolism; D004043:Dietary Fiber / Q000494:pharmacology*; D005243:Feces / Q000737:chemistry; D005260:Female; D007408:Intestinal Absorption / Q000187:drug effects; D011804:Quinolines / Q000097:blood / Q000378:metabolism* / Q000633:toxicity / Q000652:urine; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016587:Antimutagenic Agents; D002273:Carcinogens; D004043:Dietary Fiber; D011804:Quinolines; C029216:2-amino-3-methylimidazo(4,5-f)quinoline