The fermentation of lactulose in rats inoculated with Clostridium paraputrificum influences the activities of liver and intestinal xenobiotic‐metabolising enzymes

Abstract

One of the most recent hypotheses concerning the protective effect of some dietary ®bres against colon cancer implicates butyrate. Very few publications have addressed its possible in¯uence on the phase II enzymes and on the bacterial enzymes involved in the enterohepatic recirculation of toxic compounds. We used an original model of monoxenic rats oriented towards the preferential production of butyrate. Fischer male germ-free rats were mono-associated with a strain of Clostridium paraputri®cum. They were fed either a control diet or a lactulose-enriched diet for 6 weeks. In the caeco-colon the speci®c activities (SAs) of the microsomal enzymes (glutathione-Stransferase and UDP-glucuronosyl-transferase) were 1.7-fold those of the control rats. In the intestine and liver the SAs of the phase II enzymes were not altered, nor was the hepatic cytochrome P450. In the caecum of the lactulose-fed rats the SA of b-glucuronidase decreased by 27% and that of b-glucosidase doubled. The chronic consumption of lactulose doubled the total caecal short-chain fatty acids, and the production of butyrate was enhanced. Since the germ-free rats behaved differently when fed the same diets, we concluded that the fermentation products of lactulose (and not the lactulose itself) were involved in the effects we describe. The involvement of butyrate in this phenomenon is discussed.

Influência de frações da parede celular de levedura (Saccharomyces cerevisiae) sobre os índices séricos de glicose e lipídios, microbiota intestinal e produção de ácidos graxos voláteis (AGV) de cadeias curtas de ratos em crescimento

“…Especialmente o butirato, que vem sendo estudado quanto ao seu efeito no processo biológico, envolvendo a carcinogênese 33 . O butirato é a maior fonte de energia para as células epiteliais do cólon, e uma baixa concentração deste composto causa alteração celular, podendo inibir o carcinoma de cólon 43,58 .…”

Dietary fibres as “prebiotics”: Implications for colorectal cancer

“…A xenobiotic is "a chemical which is not a natural component of the organism exposed to it", and many, if not most, human carcinogens are xenobiotics. A range of enzymes (xenobiotic metabolising enzymes or XME) are classed as either phase 1 or phase 2, which function to convert these exogenous compounds into reactive metabolites or carry out conjugation reactions in order to detoxify reactive compounds for excretion, respectively [71]. Phase 1 enzymes include the cytochrome P450s (CYP) and phase 2 enzymes include glutathione S-transferase (GST) and NAD(P): quinone reductase (quinone reductase), UDP-glucuronosyltransferase (UGT), sulphotransferases, and N-acetyl transferase (NATs) [72 -74].…”

Anthocyanins in Strawberry Polyphenolic Extract Enhance the Beneficial Effects of Diets with Fructooligosaccharides in the Rat Cecal Environment

“…The administration of FOS beneficially modulates gastrointestinal functions by, e.g., increasing the production of short-chain fatty acids (SCFAs), primarily butyrate, which is an energy substrate for colonocytes [ 1 ]. Moreover, FOS decreases the activity of bacterial β-glucuronidase, which supports the undesirable transformation of xenobiotics into toxic substances [ 2 ]. Furthermore, the consumption of dietary FOS may enhance the metabolism of polyphenols [ 3 , 4 ].…”