Gut microflora

The effects of drugs in animals are usually concentration dependent and are also often animal species and site-of-action dependent " " " thus the compounds may be present naturally in diets at low levels and produce no obvious adverse effects, either on the animal, gut microflora, meat, milk or eggs. The main purpose of the use of drugs in animal feeds is to improve the animal health and welfare and often to improve growth at minimum cost to the producer.In the case of naturally produced compounds that may occur in the feedstuff s of animals, these compounds may impair animal health and performance as well as cause im-... 

Ingested plant metabolites, drugs and other compounds are processed both by the animal and by the microbial flora of the gut. The composition and activities of the gut microflora vary greatly from one animal species to another and have been very extensively reviewed." In true ruminants (sheep, cattle and deer) and in functional ruminants, such as camels and llamas, a mixed population of bacteria,... 

Even if only a relatively small fraction of ingested glucosinolates reach the circulation as the result of metabolism by the gut microflora, degradation of glucosinolates in the faecal stream may be important as a source of... 

ROWLAND I R, WISEMAN H, SANDERS T A, ADLERCREUTZ H and BOWEY E A (2000) luteriudividual variation in metabolism of soy isoflavones and lignans influence of habitual diet on equol production by the gut microflora. Nutr Cancer 36, 27-32. 

XU X, HARRIS K s, WANG H J, MURPHY p A and HENDRicH s (1995) Bioavailability of soybean isoflavones depends upon gut microflora in women. J Nutr 125, 2307-15. 

Recently, some of the specific faecal bacteria involved in the metabolism of dietary isoflavonoids were isolated (Hur et al., 2000). They have been shown to selectively convert genistin and daidzin to their respective aglycones. One of the isolated bacteria, under anoxic conditions, was further shown to metabolise genistein and daidzein to their respective dihydroxy-genistein and dihydroxy-daidzein. In the case of lignans, enterodiol and enterolactone were shown to be excreted in vivo only in rats harbouring a gut microflora (Rowland et al, 1999). 

ROWLAND I, WISEMAN H, SANDERS T, ADLERCREUTZ H and BOWEY E (1999) Metabolism of oestrogens and phytoestrogens role of the gut microflora. Biochem Soc Trans. 27 (2) 304-8. 

Nieuwenhuijs VB, Verheem A, van Duijven-bode-Beumer H, Visser MR, Verhoef J, Gooszen HG, et al The role of interdigestive small bowel motility in the regulation of gut microflora, bacterial overgrowth, and bacterial translocation in rats. Ann Surg 1998,228 188-193. 

Madden JA, Hunter JO A review of the role of the gut microflora in irritable bowel syndrome and the effects of probiotics. Br J Nutr 2002 88(suppl 1) S67-S72. 

Garcia-Tsao G, Wiest R Gut microflora in the pathogenesis of the complications of cirrhosis. Best Pract Res Clin Gastroenterol 2004 18 353-372. 

Reductions Epoxide hydroplase Azo and nitro reduction Carbonyl reductase Disulfide reduction Sulfoxide reduction Quinone reduction Reductive dehalogenation Microsomes, cytosol Gut microflora Cytosol Cytosol Cytosol Cytosol, microsomes Microsomes... 

Intestinal Metabolism Intestinal drug metabolism can occur by microflora present in the gut lumen, as well as by enzymes present in luminal fluids and in the intestinal mucosa [166], Metabolism of xenobiotics by gut microflora is low in comparison to metabolism by the gut mucosa and liver [62], However, the intestinal microflora (e.g., Bacteroides and Bifidobacteria) may play an important role in the first-pass metabolism of compounds that are poorly or incompletely absorbed by the gut mucosa, especially in the lower parts of the intestine. This bacterial metabolism is largely degradative,... 

Absorption of phenol occurs fairly rapidly via the inhalation (Hughes and Hall 1995 Ohtsuji and Ikeda 1972 Piotrowski 1971), oral (Capel et al. 1972 Edwards et al. 1986 French et al. 1974 Hughes and Hall 1995 Kao et al. 1979 Kenyon et al. 1995), and dermal (Baranowska-Dutkiewicz 1981 Hughes and Hall 1995 Piotrowski 1971) routes. Because it is an irritant, tissue damage, inflammation, or other irritation effects may occur at the sites of absorption. Because of its high pKa, ionization will not occur within the acid environment of the gut. The action of gut microflora on phenol breakdown is not expected to be significant. 

Nitrate itself is not a carcinogen. However, nitrates from foods rich in them are acted on by gut microflora and human enzymes to yield nitrite and nitrosamines. The latter are known carcinogens. 

Today, in the United States, the FDA is responsible for examining safety and efficacy data before an antibiotic or synthetic chemical may be commercialized for livestock use. This includes studies on formulations, product stability, conventional and genetic toxicity, environmental safety, metabolism, residue studies in target animals, studies on antibiotic resistance in gut microflora and on salmonella shedding in target animals. Similar requirements are part of registering these products in overseas markets. In general, after a product is discovered in the laboratory, many... 

Role of Gut Microflora in Metabolism of Glutathione Conjugates of Xenobiotics... 

Undesirable responses of prevalent gut microflora has raised interest in modiflcation of that flora by probiotic regimes, evidence of benefit is still too limited to justify general usage. 

Oleuropein, a conjugate of hydroxytyrosol (3,4-dihydroxybenzyl alcohol), is a characteristic but very variable component of olives and olive oil. After consumption of 25 ml virgin olive oil, hydroxytyrosol, 3-(9-methylhydroxytyrosol (homovanillyl alcohol), and homovanillic acid increase in plasma, as conjugates, predominantly glucuronide ° Oleuropein may be deconjugated by the gut microflora. 

Hydrolyzable tannins are comparatively restricted in the human diet and there are no human metabolic data. Studies in rats have indicated that some 63% of a dose of 1 g/kg commercial tannic acid is excreted unchanged in the feces accompanied by small amounts of gallic acid, pyrogallol, and resorcinol. Plasma after enzymic hydrolysis was found to contain 4-O-methylgallic acid, pyrogallol, and resorcinol. Urine also contained a small amount of gallic acid after enzymic hydrolysis. The most notable observation from this study is the failure of the gut microflora to metabolize the galloylglucoses efficiently, at least at this substantial dose. The viability or composition of the gut microflora was not reported. ... 

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