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Titolo:
Antimutagenic effects of wheat bran diet through modification of xenobiotic metabolising enzymes
Autore:
Helsby, NA; Zhu, ST; Pearson, AE; Tingle, MD; Ferguson, LR;
Indirizzi:
Univ Auckland, Fac Med & Hlth Sci, Auckland Canc Soc, Res Ctr, Auckland 1000, New Zealand Univ Auckland Auckland New Zealand 1000 Ctr, Auckland 1000, New Zealand Univ Auckland, Fac Med & Hlth Sci, Dept Pharmacol & Clin Pharmacol, Auckland 1000, New Zealand Univ Auckland Auckland New Zealand 1000 acol, Auckland 1000, New Zealand
Titolo Testata:
MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS
fascicolo: 1-2, volume: 454, anno: 2000,
pagine: 77 - 88
SICI:
1386-1964(20001106)454:1-2<77:AEOWBD>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
ARYL-HYDROCARBON RECEPTOR; PHENOLIC-COMPOUNDS; PLANT PHENOLS; FIBER; RATS; CANCER; CARCINOGENESIS; CELLS; GLUTATHIONE; MODULATION;
Keywords:
wheat bran; dietary fibre; phytochemicals; xenobiotic metabolising enzymes; antimutagenicity;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
50
Recensione:
Indirizzi per estratti:
Indirizzo: Ferguson, LR Univ Auckland, Fac Med & Hlth Sci, Auckland Canc Soc, Res Ctr, Private Bag92019, Auckland 1000, New Zealand Univ Auckland Private Bag 92019 Auckland New Zealand 1000 nd
Citazione:
N.A. Helsby et al., "Antimutagenic effects of wheat bran diet through modification of xenobiotic metabolising enzymes", MUT RES-F M, 454(1-2), 2000, pp. 77-88

Abstract

Diets containing wheat bran (WB) protect against cancers of the colon or breast in rats, and may be beneficial in humans. In a previous study of ratstreated with the carcinogen 2-amino-3-methylimidazo[4,5;f]quinoline (IQ), inclusion of 10% wheat bran in the diet led to an apparent reduction in IQ metabolites but not of intact IQ in plasma. In the present study, male Wistar rats were fed diets containing 0, 10 or 20% wheat bran, and effects on xenobiotic metabolising enzymes compared. Wheat bran-supplementation showed differential effects on phase I enzymes, significantly increasing the activity of hepatic cytochrome P450 isozyme CYP3A2, but slightly reducing the activity of CYP1A1/2. The activities of both hepatic phase II detoxification enzymes glutarhione-S-transferase and glucuronosyl transferase were also reduced. Western blotting revealed similar effects on expression of the proteins. Interestingly, the expression of xenobiotic metabolising enzymes (XME)in the colon appeared to be modulated independently of hepatic XME. Although the wheat bran-supplemented diet still led to an increased expression ofCYP3A, it now slightly increased CYP1A in the colon. However, 20% wheat bran significantly increased the expression of both glutathione transferase isozymes, GST A1 & A2, in the colon. Natures Gold(TM) (NG) is a commercial wheat bran derivative which is lower than wheat bran in dietary fibre, but enriched in vitamins, minerals and various phytochemicals. Dietary supplementation with 20% Natures Gold(TM) led to similar trends as seen in wheat bran-fed rats, but more potent effects in both hepatic and colonic enzymes. The significance of these changes for activation of carcinogens to mutagenic metabolites was investigated using the Salmonella/mammalian microsome mutagenicity test. The activation of IQ and benzo[a]pyrene, but not cyclophosphamide, to a mutagen by hepatic S9 from wheat bran-fed or Natures Gold(TM)-fed rats was significantly reduced compared with S9 from animals on a diet lacking wheat bran. We suggest that modulation of xenobiotic metabolising enzymes may be an important component of cancer protection by wheat bran, and this effect may relate to micronutrients or cancer-protective non-nutrient phytochemicals rather more than to dietary fibre, (C) 2000 Elsevier ScienceB.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 14/07/20 alle ore 03:01:33