Fecal Β-glucuronidase Activity Research Articles

Benefits of maternal pectin supplementation in gestation diet on vaginal microbiota of sows and intestinal health of newborn piglets.

Pectin is a proven prebiotic and widely used in human health products. This study aims to assess the impact of dietary pectin supplementation during gestation on sow vaginal microbiota and the offspring's intestinal composition. Thirty sows were randomly allocated to two groups and fed a standard diet (CON) or a standard diet supplemented with 3 g/kg pectin (PEC). Blood, feces, and vaginal swab samples from the sows and blood, intestines issue, and colonic content samples from the offspring were collected and analyzed. The results indicate that the relative abundance of vaginal Lactobacillus was notably enhanced in the PEC group and fecal β-glucuronidase (β-G) activity and plasma 17β-estradiol (E2) concentration were also significantly increased in the PEC group. Newborn piglets were found to host different microbial communities as well. At the phylum level, Proteobacteria dominated in the CON group, and Firmicutes was predominant in the PEC group. Newborn piglets in the PEC group had a lower interleukin-6 (IL-6) concentration in their plasma. The expression of intestinal cytokines of offspring was improved as well. Villus height and villus height/crypt depth (V/C) in the PEC group were extremely higher than those in the CON group. In conclusion, dietary pectin supplementation can be of benefit to both sows and newborn piglets.

Gut microbiome responds to alteration in female sex hormone status and exacerbates metabolic dysfunction

ABSTRACT Women are at significantly greater risk of metabolic dysfunction after menopause, which subsequently leads to numerous chronic illnesses. The gut microbiome is associated with obesity and metabolic dysfunction, but its interaction with female sex hormone status and the resulting impact on host metabolism remains unclear. Herein, we characterized inflammatory and metabolic phenotypes as well as the gut microbiome associated with ovariectomy and high-fat diet feeding, compared to gonadal intact and low-fat diet controls. We then performed fecal microbiota transplantation (FMT) using gnotobiotic mice to identify the impact of ovariectomy-associated gut microbiome on inflammatory and metabolic outcomes. We demonstrated that ovariectomy led to greater gastrointestinal permeability and inflammation of the gut and metabolic organs, and that a high-fat diet exacerbated these phenotypes. Ovariectomy also led to alteration of the gut microbiome, including greater fecal β-glucuronidase activity. However, differential changes in the gut microbiome only occurred when fed a low-fat diet, not the high-fat diet. Gnotobiotic mice that received the gut microbiome from ovariectomized mice fed the low-fat diet had greater weight gain and hepatic gene expression related to metabolic dysfunction and inflammation than those that received intact sham control-associated microbiome. These results indicate that the gut microbiome responds to alterations in female sex hormone status and contributes to metabolic dysfunction. Identifying and developing gut microbiome-targeted modulators to regulate sex hormones may be useful therapeutically in remediating menopause-related diseases.

Gut microbial β-glucuronidases regulate host luminal proteases and are depleted in irritable bowel syndrome.

Intestinal proteases mediate digestion and immune signaling, while increased gut proteolytic activity disrupts the intestinal barrier and generates visceral hypersensitivity, which in common in irritable bowel syndrome (IBS). However, the mechanisms controlling protease function are unclear. Here we show that members of the gut microbiota suppress intestinal proteolytic activity through production of unconjugated bilirubin. This occurs via microbial β-glucuronidase-mediated conversion of bilirubin conjugates. Metagenomic analysis of fecal samples from patients with post-infection IBS (n=52) revealed an altered gut microbiota composition, in particular a reduction in Alistipes taxa, and high gut proteolytic activity driven by specific host serine proteases compared to controls. Germ-free mice showed 10-fold higher proteolytic activity compared with conventional mice. Colonization with microbiota from high proteolytic activity IBS patients failed to suppress proteolytic activity in germ-free mice, but suppression of proteolytic activity was achieved with colonization using microbiota from healthy donors. High proteolytic activity mice had higher intestinal permeability, a higher relative abundance of Bacteroides and a reduction in Alistipes taxa compared with low proteolytic activity mice. High proteolytic activity IBS patients had lower fecal β-glucuronidase activity and end-products of bilirubin deconjugation. Mice treated with unconjugated bilirubin and β-glucuronidase overexpressing E. coli, which significantly reduced proteolytic activity, while inhibitors of microbial β-glucuronidases increased proteolytic activity. Together, these data define a disease-relevant mechanism of host-microbial interaction that maintains protease homeostasis in the gut.

Gut microbiota profiles and fecal beta-glucuronidase activity in kidney transplant recipients with and without post-transplant diarrhea.

Post-transplant diarrhea is a common complication after solid organ transplantation and is frequently attributed to the widely prescribed immunosuppressant mycophenolate mofetil (MMF). Given recent work identifying the relationship between MMF toxicity and gut bacterial β-glucuronidase activity, we evaluated the relationship between gut microbiota composition, fecal β-glucuronidase activity, and post-transplant diarrhea. We recruited 97 kidney transplant recipients and profiled the gut microbiota in 273 fecal specimens using 16S rRNA gene sequencing. We further characterized fecal β-glucuronidase activity in a subset of this cohort. Kidney transplant recipients with post-transplant diarrhea had decreased gut microbial diversity and decreased relative gut abundances of 12 genera when compared to those without post-transplant diarrhea (adjusted p value<.15, Wilcoxon rank sum test). Among the kidney transplant recipients with post-transplant diarrhea, those with higher fecal β-glucuronidase activity had a more prolonged course of diarrhea (≥7days) compared to patients with lower fecal β-glucuronidase activity (91% vs 40%, p=.02, Fisher's exact test). Our data reveal post-transplant diarrhea as a complex phenomenon with decreased gut microbial diversity and commensal gut organisms. This study further links commensal bacterial metabolism with an important clinical outcome measure, suggesting fecal β-glucuronidase activity could be a novel biomarker for gastrointestinal-related MMF toxicity.

Effects of Lactic Acid Bacteria-Fermented Soymilk on Isoflavone Metabolites and Short-Chain Fatty Acids Excretion and Their Modulating Effects on Gut Microbiota.

Lactobacillus rhamnosus strain ASCC 1520 with high soy isoflavone transformation ability was used to ferment soymilk and added to the diet of mice. The impact of L. rhamnosus fermentation on soy isoflavone metabolites and intestinal bacterial community, in conjunction with fecal enzyme activity and short-chain fatty acids (SCFA) excretion was evaluated. Antibiotics intervention resulted in a decrease in fecal enzyme activities and SCFA. Although long-term intake of soymilk or L. rhamnosus-fermented soymilk did not affect the fecal β-glucuronidase and β-galactosidase activities, it improved the β-glucosidase activity when antibiotics were concomitantly administered. Soymilk or fermented soymilk administration increased the isoflavone metabolites (O-DMA and equol) excreted in urine. Antibiotics decreased the daidzein excretion and its metabolites but showed little effect on glycitein and genistein excretion. Principal coordinates analysis (PCoA) of the 16s rRNA gene sequencing data found a remarkable shift in gut microbiota after soymilk administration and antibiotics treatment. Matastats test of the relative abundance of bacterial taxa revealed Odoribacter (Bacteroidales family), Lactobacillus (Lactobacillales order), and Alistipes (Rikenellaceae family) were enriched in soymilk while bacterial taxa from Bacteroides and Lactobacillus were enriched in L. rhamnosus-fermented soymilk. Furthermore, there was less decrease in bacterial taxa with fermented soymilk group even when antibiotics were concomitantly administered. Overall, this study revealed that the gut microbiota of a healthy host is enough for the whole isoflavone metabolism under normal conditions. Feeding mice with L. rhamnosus-fermented soymilk improved fecal enzyme activity and kept the balance of the gut mirobiota when antibiotics were used. PRACTICAL APPLICATION: Feeding mice with L. rhamnosus-fermented soymilk improved fecal enzyme activity and kept the balance of the gut mirobiota when antibiotics were used.

Ethylacetate fractional extract of Mentha spicata attenuates irinotecan‐induced mucositis in mice

Irinotecan induced‐mucositis is an inflammatory event of intestine that has negative impact on patient health and affect treatment efficacy. Irinotecan first metabolized in the liver by a carboxylesterase (CES) to the active cytotoxic metabolite (SN‐38), which subsequently glucuronidated by hepatic enzymes to the inactive metabolite SN38G. The SN‐38G undergo deconjugation in the intestine liberating the active SN‐38 via β‐glucuronidase produced by the intestinal bacterial flora. Consequently, SN‐38 triggers inflammation events characterized by delayed intestinal mucositis and diarrhea. This study aims to ameliorate irinotecan‐induced mucositis and diarrhea in mice model using ethylacetate fractional extraction of Mentha spicata(EAEMS), an edible widley consumed plant. Mice model of irinotecan‐induced mucositis and diarrhea produced by I.P injection of irinotecan (75mg/Kg/day) for 4 days. EAEMS administered orally (160mg/kg) twice daily for 7 days starting one day before irinite can dose. Diarrhae scores and mice body weight variation measured to assess the severity of mucositis and diarrhea. Jejunal IL‐1β and MPO measured as markers of intestinal inflammation. β‐glucuronidase activity in fecal pelletes were measured also. Compared to model control mice, results revealed that animals received EAEMS presented with significantly lower diarrhea scores and body weight loss. Furthermore, jejunal IL‐1β and MPO significantly reduced and associated with significant inhibition of fecal β‐glucuronidase activity in animals received EAEMS compared to model control mice. In conclusion, we showed for the first time that EAEMS has a protective effect against irinotecan‐induced mucositis and diarrhea, an effect suggested to be mediated by inhibition of bacterial β‐glucuronidase activity. This promising result might have a therapeutic application in cancer patients suffering from delayed‐onset diarrhea due to irinotecan treatment.Support or Funding InformationUniversity of Baghdad, College of PharmacyThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Активность фекальной β-глюкуронидазы у больных с воспалительными заболеваниями кишечника

The aim of research: to investigate the activity of β-glucuronidase in coprofiltrates (OR feces) in patients with inflammatory bowel diseases - UC and CD at different severity levels (form of disease- mild, middle, severe) and to determine the significance as a laboratory criterion in the diagnosis, treatment and prognosis of IBD. Materials and methods. In research was prospectively studied 105 patients - 82 patients with IBD (29 patients with CD, 53 patients with UC) and 23 healthy volunteers without clinical laboratory indicators of inflammatory processes in the organism and diseases of the colon as the comparison group. The activity of β-glucuronidase in feces was determined using phenolphthalein glucuronide as a substrate. Results. The activity of β-glucuronidase in feces in patients with IBD did not differ from the healthy group (comparison group): in patients with IBD - 86.81 ± 8.4 μM / g / hr, and in norm, healthy group (comparison group) 76.04 ± 10.13 μM / g / hr (p> 0.05). Also we did not find significant differences in the activity of β-glucuronidase in patients with CD and UC, in comparison with the norm (healthy group), or between groups of patients with IBD (CD and UC). In both forms of IBD, we did not find significant differences in the activity of β-glucuronidase in patients with severe, mild or middle severity level of disease, as in comparison with healthy group so as between group of severity level. Conclusion. We have established that the activity of fecal β-glucuronidase in patients with different severity levels CD and UC did not differ from in patients of healthy group. Determination of the activity of fecal β-glucuronidasecan not use as objective laboratory criteria for determining the severity of IBD and predicting the course of the disease and, apparently, does not have essential value in the pathogenesis of IBD.

β-glucuronidase activity and enterolactone concentration in ruminal fluid, plasma, urine, and milk of Holstein cows fed increased levels of flax (Linum usitatissimum) meal

The main mammalian lignan present in milk of dairy cows fed flax products is enterolactone (EL), but the relationship between EL concentration in milk and body fluids when cows are fed increased proportions of flax meal (FM) is unknown. The objectives were to investigate the effects of increased levels of FM on EL concentration in milk, plasma, urine, and ruminal fluid and the activity of β-glucuronidase in ruminal fluid and feces. Eight rumen-cannulated cows were assigned to a double 4×4 Latin square design with four 21 d periods and four diets: control diet with no FM (CON) or a diet with 50, 100 and 150g/kg of FM. Concentrations of EL in urine, ruminal fluid, milk, and plasma increased linearly with FM supplementation. Spearman’s correlation coefficients were significant for all comparisons except that only a trend was observed between concentration of EL in urine and that in ruminal fluid before feeding. The strongest correlation was observed between EL concentration in ruminal fluid post-feeding and that in milk. Feeding increased proportions of FM in the diet had no effect on β-glucuronidase activity. Unlike to what is observed in non-ruminant animals, present results suggest that the activity of β-glucuronidase in the rumen is of little importance for the absorption of EL and its transfer in milk and other physiological fluids. Further studies are required to better understand and improve EL production and absorption, which could contribute to enhance animal health and the transfer of antioxidant components in milk.

Effects of duodenal infusion of sunflower oil on β-glucuronidase activity and enterolactone concentration in dairy cows fed flax meal

Microbial β-glucuronidase activity is important for the absorption of enterolignans. This study was performed to evaluate the effects of dietary flax meal and abomasal infusion of sunflower oil (SO) on activity of β-glucuronidase in ruminal fluid and feces, and concentration of enterolactone (EL) in ruminal fluid, plasma, urine and milk. Eight rumen fistulated lactating Holstein cows were assigned to a double 4×4 Latin square design with a 2×2 factorial arrangement of treatments: (1) control diet with no FM (CO); (2) diet containing 137g/kg flax meal (FM); (3) CO and infusion of 250g SO/d in the abomasum; and (4) FM and infusion of 250g SO/d in the abomasum. Activity of β-glucuronidase in ruminal fluid was similar among diets. Cows fed the FM diets had lower fecal β-glucuronidase activity than those fed the CO diets. Infusion of SO lowered fecal β-glucuronidase activity. Supplementation with FM increased EL concentration in plasma, urine and prefeeding ruminal fluid, and SO reduced EL concentration in ruminal fluid before feeding. Dietary FM and SO infusion had no effect on milk EL concentration. Overall, the metabolism of flax lignans and the absorption of enterolignans were not affected by the presence of SO, a rich source of n-6 fatty acids, in the intestine as indicated by similar concentrations of EL in ruminal fluid (pool of 2, 4 and 6h postfeeding), plasma and urine. These results suggest that the effect of fat on the metabolism of lignans may differ between results observed in the present experiment with ruminant animals and those obtained in previous studies with non-ruminant animals.

Dietary flax meal and abomasal infusion of flax oil on microbial β-glucuronidase activity and concentration of enterolactone in ruminal fluid, plasma, urine and milk of dairy cows

This study was performed to evaluate the effects of dietary flax meal (FM) and abomasal infusion of flax oil (FO) and their interaction on activity of β-glucuronidase in ruminal fluid and feces, and concentration of the mammalian lignan enterolactone (EL) in ruminal fluid, plasma, urine, and milk. Rumen fermentation characteristics and the pH in ruminal fluid and feces were also investigated to determine any potential interference with β-glucuronidase activity and EL concentration. Eight rumen fistulated lactating Holstein cows were assigned to a double 4×4 Latin square design with a 2×2 factorial arrangement of treatments: (1) control diet with no FM (CON); (2) diet containing 124g/kg FM (FMD) in the dry matter (DM); (3) CON and 250g FO/day infused in the abomasum; and (4) FMD and 250g FO/day infused in the abomasum. Abomasal infusion of FO had no effect on β-glucuronidase activity in the gastrointestinal tract and EL concentration of ruminal fluid, plasma, urine, and milk. Dietary FM and abomasal infusion of FO had no effect on fecal pH and microbial activity of β-glucuronidase in ruminal fluid and feces. Dietary FM increased concentrations of EL in ruminal fluid, plasma, urine, and milk. Molar proportion of propionate was increased and that of isovalerate was decreased with FM supplementation. Abomasal infusion of FO had no effect on ruminal concentration of ammonia N. Dietary FM had no effect on ruminal pH. As abomasal infusion of FO had no effect on β-glucuronidase activity in the gastro-intestinal tract and EL concentration, our results suggest that polyunsaturated fatty acids such as n-3 do not interfere with the absorption of mammalian lignans. Moreover, feeding 124g/kg DM FM with a source of FA rich in n-3 bypassing the rumen increases EL concentration in physiological fluids of dairy cows, especially milk, which can be used as a strategy to optimize the concentration of mammalian lignans in milk and their potential beneficial effects on human health.

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

The administration of fructooligosaccharides (FOS) beneficially modulates gastrointestinal functions and may enhance the metabolism of polyphenols. However, different polyphenolic components in the diet may have different influences on the activities of the digestive enzymes and microbiota in the gastrointestinal tract. Therefore, a 4-week study of forty-eight male Wistar rats was conducted to investigate the physiological response of the rat cecal environment to diets without and with FOS that contained two different strawberry polyphenolic extracts, specifically EP (polyphenolic profile 60, 35, 5, and 0% ellagitannins, proanthocyanidins, flavonols, anthocyanins, respectively) and EPA (polyphenolic profile: 50, 35, 6, and 9%, respectively). When combined with FOS, both extracts beneficially enhanced the acidification of the cecal digesta (P≤0.05 vs the groups without extracts), but the dietary combination of EPA and FOS elicited the greatest reduction in putrefactive short-chain fatty acid production and the lowest fecal β-glucuronidase activity in the cecum (P≤0.05 vs group EP). Moreover, the addition of dietary FOS elevated the metabolism of the examined strawberry extracts in the cecum and thereby increased the concentrations of the metabolites in the cecal digesta and urine (P≤0.05 vs the group with cellulose). Overall, both strawberry extracts modulated the effects of FOS in the gastrointestinal tract; however, the combination with EPA extract that contained anthocyanins exhibited greater beneficial effects in the lower gut environment than the EP extract.

Purple Rice Extract Supplemented Diet Reduces DMH-Induced Aberrant Crypt Foci in the Rat Colon by Inhibition of Bacterial β-Glucuronidase

Purple rice has become a natural product of interest which is widely used for health promotion. This study investigated the preventive effect of purple rice extract (PRE) mixed diet on DMH initiation of colon carcinogenesis. Rats were fed with PRE mixed diet one week before injection of DMH (40 mg/kg of body weight once a week for 2 weeks). They were killed 12 hrs after a second DMH injection to measure the level of O6-methylguanine and xenobiotic metabolizing enzyme activities. In rats that received PRE, guanine methylation was reduced in the colonic mucosa, but not in the liver, whereas PRE did not affect xenobiotic conjugation, with reference to glutathione-S-transferase or UDP-glucuronyl transferase. After 5 weeks, rats that received PRE with DMH injection had fewer ACF in the colon than those treated with DMH alone. Interestingly, a PRE mixed diet inhibited the activity of bacterial β-glucuronidase in rat feces, a critical enzyme for free methylazoxymethanol (MAM) release in the rat colon. These results indicated that purple rice extract inhibited β-glucuronidase activity in the colonic lumen, causing a reduction of MAM-induced colonic mucosa DNA methylation, leaded to decelerated formation of aberrant crypt foci in the rat colon. The supplemented purple rice extract might thus prevent colon carcinogenesis by the alteration of the colonic environment, and thus could be further developed for neutraceutical products for colon cancer prevention.

Prebiotic effects of almonds and almond skins on intestinal microbiota in healthy adult humans

Almonds and almond skins are rich in fiber and other components that have potential prebiotic properties. In this study we investigated the prebiotic effects of almond and almond skin intake in healthy humans. A total of 48 healthy adult volunteers consumed a daily dose of roasted almonds (56 g), almond skins (10 g), or commercial fructooligosaccharides (8 g) (as positive control) for 6 weeks. Fecal samples were collected at defined time points and analyzed for microbiota composition and selected indicators of microbial activity. Different strains of intestinal bacteria had varying degrees of growth sensitivity to almonds or almond skins. Significant increases in the populations of Bifidobacterium spp. and Lactobacillus spp. were observed in fecal samples as a consequence of almond or almond skin supplementation. However, the populations of Escherichia coli did not change significantly, while the growth of the pathogen Clostridum perfringens was significantly repressed. Modification of the intestinal microbiota composition induced changes in bacterial enzyme activities, specifically a significant increase in fecal β-galactosidase activity and decreases in fecal β-glucuronidase, nitroreductase and azoreductase activities. Our observations suggest that almond and almond skin ingestion may lead to an improvement in the intestinal microbiota profile and a modification of the intestinal bacterial activities, which would induce the promotion of health beneficial factors and the inhibition of harmful factors. Thus we believe that almonds and almond skins possess potential prebiotic properties.

The Role of Intestinal Microflora in Anti-Inflammatory Effect of Baicalin in Mice

Baicalin, a main constituent of the rhizome of Scutellaria baicalensis, is metabolized to baicalein and oroxylin A in the intestine before its absorption. To understand the role of intestinal microflora in the pharmacological activities of baicalin, we investigated its anti-inflammatory effect in mice treated with and without antibiotics. Orally administered baicalin showed the anti-inflammatory effect in mice than intraperitoneally treated one, apart from intraperitoneally administered its metabolites, baicalein and oroxylin A, which potently inhibited LPS-induced inflammation. Of these metabolites, oroxylin A showed more potent anti-inflammatory effect. However, treatment with the mixture of cefadroxil, oxytetracycline and erythromycin (COE) significantly attenuated the anti-inflammatory effect of orally administered baicalin in mice. Treatment with COE also reduced intestinal bacterial fecal β-glucuronidase activity. The metabolic activity of human stools is significantly different between individuals, but neither between ages nor between male and female. Baicalin was metabolized to baicalein and oroxylin A, with metabolic activities of 1.427 ± 0.818 and 1.025 ± 0.603 pmol/min/mg wet weight, respectively. Baicalin and its metabolites also inhibited the expression of pro-inflammatory cytokines, TNF-α and IL-1β, and the activation of NF-κB in LPS-stimulated peritoneal macrophages. Of them, oroxylin A showed the most potent inhibition. Based on these findings, baicalin may be metabolized to baicalein and oroxylin A by intestinal microflora, which enhance its anti-inflammatory effect by inhibiting NF-κB activation.

Effects of Konjac Glucomannan on Putative Risk Factors for Colon Carcinogenesis in Rats Fed a High-Fat Diet

The aim of this study was to determine effects of konjac glucomannan (KGM) in a high fat corn oil diet on risk factors of colon carcinogenesis, that is, fecal β-glucuronidase, mucinase, and bile acids, and on preventive factors, that is, fecal microflora and cecal short-chain fatty acids (SCFAs). Sprague-Dawley rats (n = 8 animals per group) were fed a normal-fat fiber-free (5% corn oil, w/w) or high-fat (25% corn oil, w/w) diet containing no fiber, KGM (5%, w/w), or inulin (5%, w/w, as a prebiotic control) for 4 weeks. Results indicated that the high-fat fiber-free diet significantly elevated the fecal β-glucuronidase and mucinase activities and total bile acid concentration and decreased cecal SCFA contents, as compared with its normal-fat counterpart. The incorporation of KGM, as well as inulin, into the high-fat fiber-free diet beneficially reduced the fecal β-glucuronidase and mucinase activities and lithocholic acid (secondary bile acid) concentration. Although KGM elevated the daily fecal total bile acid excretion, the change was due to the primary, instead of the secondary, bile acids. In addition, KGM beneficially promoted the daily fecal excretion of bifidobacteria and lactobacilli and cecal SCFA contents, as compared with the high-fat fiber-free diet. Therefore, the present study suggests that KGM potentially attenuated the high fat-induced risk in colon carcinogenesis.

Adhesion Activity ofLactobacillus plantarumPM 008 Isolated from Kimchi on the Intestine of Mice

Lactic acid bacteria (LAB), including L. plantarum isolated from Kimchi, are beneficial and safe microorganisms that improve disturbances of the indigenous microflora and the host's immune system. The adhesion abilities of Kimchi-derived L. plantarum PM008 and yogurt-derived L. casei were measured in vitro and in vivo. When L. plantarum or L. casei was incubated with Caco-2 cells, these Lactobacillus strains were potently attached. When these strains were orally administered to mice, the LABs were attached on the large intestine of mice. The attachment of L. plantarum on murine intestine or Caco-2 intestinal epithelial cell lines was more potent than that of L. casei, although numbers of LAB between their feces were not different. Treatment with either L. plantarum or L. casei for 14 days suppressed fecal β-glucuronidase activity, although treatment for one day did not affect it. L. plantarum showed more potent inhibition than L. casei. In addition, L. plantarum and L. casei were stable to artificial gastric and intestinal juice. L. plantarum was more stable than L. casei. Based on these findings, the survival and adhesion effects of orally administered LAB strains in the intestine may increase numbers of LAB in intestine and express their biological activities.

Comparative Effects of Cellulose and Soluble Fibers (Pectin, Konjac Glucomannan, Inulin) on Fecal Water Toxicity toward Caco-2 Cells, Fecal Bacteria Enzymes, Bile Acid, and Short-Chain Fatty Acids

The aim of this study was to compare the effects of cellulose and three soluble dietary fibers, pectin, konjac glucomannan (KGM), and inulin, on the cytotoxicity and DNA damage of fecal water-treated Caco-2 cells, a human colon adenocarcinoma cell line, and to investigate the fecal components that potentially modulate the fecal toxicity, that is, bacterial enzymes, bile acids, and short-chain fatty acids. Six-week-old BALB/cJ mice were randomly allocated to consume an AIN-93 diet that contained no dietary fiber (fiber-free) or 5% (w/w) cellulose, pectin, KGM, and inulin for 3 weeks. Feces were collected during days 18-21. Fecal waters were co-incubated with Caco-2 cells to determine the cytotoxicity and DNA damage. In addition, the fecal bacterial enzymes, bile acids, and short-chain fatty acids were determined. Results indicated that all fiber diets similarly increased the survival rate (%) of fecal water-treated Caco-2 cells as compared with the fiber-free diet. The inhibition of fecal water-induced DNA damage in Caco-2 cells was greater for the pectin and inulin diets than for the cellulose and KGM diets. In contrast, cellulose exerted the greatest inhibitory effect on the fecal β-glucuronidase activity. Cellulose and all soluble dietary fibers reduced the secondary bile acid concentrations in the fecal water, but only soluble fibers increased the fecal concentrations of short-chain fatty acids, as compared with no fiber. Therefore, this study suggests that all dietary fibers substantially reduced the fecal water toxicity, which is associated with decreased secondary bile acid levels by all fibers, reduced fecal β-glucuronidase activity by cellulose, and increased short-chain fatty acid levels by soluble dietary fibers.

Constipation Is Relieved More by Rye Bread Than Wheat Bread or Laxatives without Increased Adverse Gastrointestinal Effects ,

Rye bread and lactobacilli modify the colonic environment and have the potential to relieve constipation and could be a safe and convenient alternative to laxatives. The effects of rye bread and cultured buttermilk with Lactobacillusrhamnosus GG (LGG) on bowel function and colon metabolism were investigated and compared with laxatives in 51 constipated adults. They were randomized to receive whole-grain rye bread (minimum 240 g/d), LGG (2 x 1010 colony-forming units/d), whole-grain rye bread (minimum 240 g/d) + LGG (2 x 1010 colony-forming units/d), white wheat bread (maximum 192 g/d), or laxatives (as usual for a participant) for 3 wk. Participants recorded their dietary habits, bowel function, and gastrointestinal symptoms. Fecal weight, pH, SCFA and bacterial enzyme activities, total intestinal transit time (TITT), and breath hydrogen were determined. Rye bread, compared with white wheat bread, shortened TITT by 23% (P = 0.040), increased weekly defecations by 1.4 (P = 0.014), softened feces [odds ratio (OR) 3.98; P = 0.037], eased defecation (OR 5.08; P = 0.018), increased fecal acetic acid and butyric acid contents by 24% (P = 0.044) and 63% (P <0.001), respectively, and reduced fecal β-glucuronidase activity by 23% (P = 0.014). Compared with laxatives, rye bread reduced TITT by 41% (P = 0.006), fecal β-glucuronidase activity by 38% (P = 0.033), and fecal pH by 0.31 units (P = 0.006). LGG did not relieve constipation or significantly affect colonic metabolism. Gastrointestinal adverse effects did not significantly differ among the study groups. In conclusion, rye bread relieves mild constipation and improves colonic metabolism compared with white wheat bread and commonly used laxatives without increasing gastrointestinal adverse effects.

Effects of β-Glucuronidase-Deficient and Lycopene-Producing Escherichia coli Strains on Formation of Azoxymethane-Induced Aberrant Crypt Foci in the Rat Colon

We tried to inhibit the formation of azoxymethane-induced aberrant crypt foci (ACF) in the rat intestine by feeding a culture of a β-glucuronidase-deficient Escherichia coli strain or a cell suspension of a lycopene-producing E. coli strain. Feeding of the former culture to F344 rats did not decrease fecal β-glucuronidase activity or the number of ACF compared with the control β-glucuronidase-proficient groups. However, a significant positive correlation between the fecal β-glucuronidase activity and the ACF number was observed among groups treated with cultures of β-glucuronidase-proficient and -deficient strains. In the group treated with lycopene-producing cells, the number of ACF was significantly lower than that in the control group. A vegetable juice containing a larger amount of lycopene than a cell suspension of the lycopene-producing E. coli also decreased the number of ACF to the same extent as a cell suspension of the lycopene-producing bacteria. These results suggest that feeding of the β-glucuronidase-deficient E. coli is not very effective in preventing colon carcinogenesis, although activity of the fecal β-glucuronidase is associated with AOM-induced ACF formation, and that lycopene-producing intestinal bacteria can effectively prevent colon carcinogenesis.

Yogurt consumption and estrogen metabolism in healthy premenopausal women

Dietary modification of intestinal microflora by yogurt or Lactobacilli supplementation has been shown to decrease fecal β-glucuronidase activity, thereby possibly affecting estrogen metabolism and lowering breast cancer risk. To determine if yogurt consumption modifies fecal β-glucuronidase activity and plasma and urine estrogen concentrations, 16 women (24.8 ± 1.0 y; mean ± SEM) were assigned randomly to two groups, control (CON;n=7) or yogurt treatment (YOG;n=9). Control subjects refrained from yogurt consumption for three months, whereas the YOG group consumed two cups (454 g/d) of commercially produced yogurt made with a culture (1:1 ratio) of Lactobacillus delbrueckii ssp bulgaricus and Lactococcus salivarius ssp thermophilus (> 10 7 colony forming units/g yogurt) for three consecutive months. Prior yogurt consumption did not exceed 4–6 cups/month and subjects consumed their usual diets during the study. Three-day diet records, fasting mid-luteal blood, and 24 h urine collections were obtained during three consecutive days of subjects' first-, second-, and fourth-menstrual cycles. Fecal samples were collected once during each menstrual cycle. Dietary nutrient intakes were not significantly different within or between groups throughout the study. The YOG group was consuming a low-fat diet (19–22% of total calories). Fecal β-glucuronidase activity and plasma and urinary estrone and estradiol-17β concentrations were assessed following baseline and months one and three for CON and YOG consumers. No significant differences were observed within or between groups for any of the aforementioned biochemical variables. In conclusion, three months of yogurt consumption did not alter fecal β-glucuronidase activity or plasma and urine estrogen concentrations.