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Dose effects of the food spice cardamom on aspects of hamster gut physiology
Abstract
The dose effects of pectic polysaccharide-rich extract from the food spice cardamom (Amomum villosum Lour.) on intestinal environment were investigated. The results showed that pectic polysaccharides and hemicellulose were the major polysaccharides in the cardamom extract. The administration of cardamom extract (0.5 and 1.5 g/100 g diet) effectively (p < 0.05) shortened hamster gastrointestinal transit time by approximately 58%, increased fecal moisture contents (148-174%), increased SCFA concentrations in hindgut (4.0- to 7.8-fold), decreased the activities of beta-D-glucuronidase (by 71.4-85.7%), beta-D-glucosidase (by 24.3-51.5%), mucinase (by 63.6-72.7%), and urease (by 88.8-90.4%) in feces, and reduced the production of toxic ammonia (by 16.1-64.5%). These findings suggested that the consumption of cardamom extract (at least 0.5 g/100 g diet or 40 mg/day) might exert a favorable effect on improving the gastrointestinal milieu, and also provide a clue to substantiate its traditional therapeutic uses and dosage for intestinal health improvement.
... The medicinal active ingredients of AVL are composed of volatile and nonvolatile ingredients. Common volatile ingredients include borneol (Bor), camphor (CAMP), bornyl acetate (BA), etc. Common nonvolatile ingredients include catechins (Cat), QR, etc. Research has proved that AVL can increase the peristalsis of the small intestine, which is beneficial to improve gastrointestinal function [12]. It is an effective herbal medicine to relieve constipation. ...
Berberine (BBR) is used to treat cancer, inflammatory conditions, and so on. But the side effects of BBR causing constipation should not be ignored. In clinical application, the combination of Amomum villosum Lour. (AVL) and BBR can relieve it. However, the effective ingredients and molecular mechanism of AVL in relieving constipation are not clear. A small intestine propulsion experiment was conducted in constipated mice to screen active ingredients of AVL. We further confirmed the molecular mechanism of action of the active ingredient on BBR-induced constipation. Quercetin (QR) was found to be the effective ingredient of AVL in terms of relieving constipation. QR can efficiently regulate the microbiota in mice suffering from constipation. Moreover, QR significantly raised the levels of substance P and motilin while lowering those of 5-hydroxytryptamine and vasoactive intestinal peptide; furthermore, it also increased the protein expression levels of calmodulin, myosin light-chain kinase, and myosin light chain. The use of QR in combination with BBR has an adverse effect-reducing efficacy. The study provides new ideas and possibilities for the treatment of constipation induced by BBR.
... (Zingiberaceae, A. villosum) has been used as a traditional Chinese medicine for the treatment of gastrointestinal diseases for more than 1300 years [1]. A. villosum is widely distributed in South and East Asia [2]. Accumulating studies demonstrated that the major bioactive components of A. villosum included volatile oils, flavonoids, terpenoids and polysaccharides, which showed anti-inflammation, anti-oxidant, antiulceration and anti-microbial activities [3][4][5][6][7][8][9]. ...
Amomum Villosum Lour. (A. villosum) is a folk medicine that has been used for more than 1300 years. However, study of the polysaccharides of A. villosum is seriously neglected. The objectives of this study are to explore the structural characteristics of polysaccharides from A. villosum (AVPs) and their effects on immune cells. In this study, the acidic polysaccharides (AVPG-1 and AVPG-2) were isolated from AVPs and purified via anion exchange and gel filtration chromatography. The structural characteristics of the polysaccharides were characterized by methylation, HPSEC-MALLS-RID, HPLC, FT-IR, SEM, GC-MS and NMR techniques. AVPG-1 with a molecular weight of 514 kDa had the backbone of → 4)-α-d-Glcp-(1 → 3,4)-β-d-Glcp-(1 → 4)-α-d-Glcp-(1 →. AVPG-2 with a higher molecular weight (14800 kDa) comprised a backbone of → 4)-α-d-Glcp-(1 → 3,6)-β-d-Galp-(1 → 4)-α-d-Glcp-(1 →. RAW 264.7 cells were used to investigate the potential effect of AVPG-1 and AVPG-2 on macrophages, and lipopolysaccharide (LPS) was used as a positive control. The results from bioassays showed that AVPG-2 exhibited stronger immunomodulatory activity than AVPG-1. AVPG-2 significantly induced nitric oxide (NO) production as well as the release of interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α), and upregulated phagocytic capacities of RAW 264.7 cells. Real-time PCR analysis revealed that AVPG-2 was able to turn the polarization of macrophages to the M1 direction. These results suggested that AVPs could be explored as potential immunomodulatory agents of the functional foods or complementary medicine.
... Previous studies have reported that the water extraction of A. fructus can significantly enhance the amplitude of the basic electrical rhythm on electrogastrograms and can also promote intestinal peristalsis. Furthermore, there are clear differences in the resumption of gurgling sounds, along with exhaust and defecation times, when compared between patients receiving water extraction of A. fructus and patients receiving conventional forms of modern medicine, such as enteral nutrition solution via nasal feeding (Huang et al., 2007;Chen et al., 2018;Suo et al., 2018). ...
Background
Amomi fructus is a famous traditional Chinese medicine (TCM) that can exert beneficial effects during the treatment of gastrointestinal diseases and is used widely in China and other countries in Southeast Asia. However, the nonvolatile active ingredients that are present in the water extractions from A. fructus used to treat gastrointestinal diseases have yet to be elucidated. The goal of this study was to identify the nonvolatile active ingredients of A. fructus.
Methods
We used an in situ single-pass intestinal perfusion (SPIP) model to identify the active ingredients of A. fructus that play significant roles in gastrointestinal absorption. In addition, we developed a high-performance liquid chromatography (HPLC) method to identify key fractions in intestinal outflow perfusate.
Results
Nineteen components were identified in a water extraction from A. fructus; these exhibited different absorption capabilities in different intestinal segments. Of these, six components were determined by the newly developed HPLC method: catechin, vanillic acid, epicatechin, polydatin, isoquercitrin, and quercitrin.
Conclusions
The current study aimed to identify the active ingredients present in water extractions prepared from A. fructus in a single-intestinal perfusate from rats. Our findings provide an experimental basis to explain the pharmacodynamic actions of A. fructus.
... The composition of WKN includes the following nine Chinese herbs: Radix Scutellariae, Rhizoma Zingiberis, Radix Codonopsis pilosulae, Rheum rhabarbarum, Radix Bupleuri, Radix Curcumae, Magnolia officinalis bark, Radix Paeoniae alba, and Rhizoma Corydalis (12). Pharmacological studies have indicated that Pinellia spp., Radix Codonopsis pilosulae, Villosum spp., Magnolia officinalis and Rheum rhabarbarum may strengthen GI smooth muscle tension (14)(15)(16)(17)(18)(19). Furthermore, Scutellaria baicalensis and Coptis chinensis have been reported to function as anti-inflammatory and antiallergic mediators, and serve a dual-directional role in the regulation of GI smooth muscle, which may provide a pharmacological basis for WKN as a treatment for FD (20)(21)(22). ...
Functional dyspepsia (FD) is a non-organic gastrointestinal disorder that has a marked negative impact on quality of life. Compared with conventional pharmacological therapies, the traditional Chinese medicine weikangning (WKN) is a safe and effective treatment for FD. The present study aimed to determine the molecular mechanisms underlying the efficacy of WKN. The effect of different concentrations of WKN on the proliferation of the human gastric mucosal epithelial cell line GES-1 was assessed. The optimal WKN concentration to promote cell proliferation was determined, and this concentration was used to examine the effect of WKN compared with a domperidone-treated positive control group on the antioxidant capacity of GES-1 cells. The effect of WKN treatment on the growth and antioxidant activity of GES-1 cells was also assessed following nuclear factor erythroid 2 like 2 (Nrf2) knockdown. The optimal WKN dose for promoting cell growth was determined to be 0.025 mg/ml; at this concentration the expression of the antioxidant proteins glutathione S-transferase P and superoxide dismutase 2 (SOD2) were significantly elevated (P<0.0001). Furthermore, the amount of reduced glutathione and activity of SOD2 were significantly increased (P<0.0001 and P<0.01, respectively), and malondialdehyde content was significantly decreased, compared with the controls (P<0.001). With WKN treatment, the transcription of Nrf2 and its downstream genes were significantly upregulated (P<0.01), and the level and nuclear distribution of Nrf2 protein was also markedly increased. Following Nrf2 silencing, the protective antioxidant effects of WKN treatment were impaired and GES-1 cell proliferation decreased. The results of the present study suggest that the efficacy of WKN in protecting gastric mucosal epithelial cells in FD is antioxidant-dependent and mediated by Nrf2 activation.
... Los compuestos volátiles responsables del aroma y el sabor del cardamomo forman parte de una mezcla de aceites volátiles, como el acetato de α-terpenilo, 1,8-cineol, α-tepinilo, limoneno, sabineno y pineno, entre otros, composición que constituye una de las características distintivas de cada país productor, ya que el perfil de volátiles dependerá de la variedad, las condiciones agroclimáticas y el manejo del cultivo. Este factor diferenciador permite el direccionamiento del producto a los grandes consumidores con preferencias definidas (HUANG et al., 2000(HUANG et al., , 2007. ...
Resumen El objetivo de este trabajo radicó en encontrar las condiciones óptimas para la obtención de un aceite de cardamomo, extraído por FSC a escala semi-industrial, con rendimientos iguales o superiores a los métodos convencionales, pero con calidad sensorial y técnica competitiva para los mercados internacionales, así como la producción de microcápsulas del aceite que permitieran incrementar la solubilidad, sin afectar las características sensoriales como aroma y sabor. Las semillas de cardamomo se obtuvieron en el municipio de Tarso, (Antioquia, Colombia), se acondicionaron para ser extraídas por FSC a escala de laboratorio a 200.400 bar y 50 °C, 60 °C, con tres réplicas al centro a 300 bar y 55 °C, de acuerdo a un diseño central compuesto y la optimización de los resultados por superficie de respuesta según el rendimiento (%) y contenido de 1,8-cineol y acetato de α-terpenilo. Las condiciones finales (50 °C, 400 bar) se escalaron a un extractor semi-industrial hasta obtener un aceite con un rendimiento de 8,54 ± 1,09% y una concentración de 1,8-cineol (28,37 ± 1,80% p/p) y acetato de α-terpenilo (32,93 ± 1,24% p/p), analizados por GC-FID. La caracterización complementaria del aceite se encaminó al perfil sensorial y pruebas fisicoquímicas, con un resultado de atributos balanceados (herbal: 3,0, menta: 2,6, floral: 2,4 y cítrico: 2,3) e índice de color entre (+2 y +20). El aceite fue microencapsulado por secado por aspersión con una mezcla de goma arábiga, maltodextrina y almidón modificado (4/6, 1/6, 1/6) respectivamente. Se obtuvieron microcápsulas con un tamaño de partícula entre 12,2 y 25,78 µm y una distribución de la misma en solución acuosa de 13,18 µm, lo que permitió el aumento de la solubilidad del aceite en una matriz polar a temperatura ambiente.
... Several studies have demonstrated that the consumption of some carbohydrates such as polysaccharides and oligosaccharides could enhance both enzyme and growth activities of certain intestinal microflora, support normal intestinal structure, and lower the risk of gastrointestinal disease (Chau et al., 2005;Huang et al., 2007b). For example, Huang et al. (2008b) investigated the effects of water-soluble carbohydrate concentrate (WSCC) prepared from Chinese jujubes on intestinal health in a hamster model. ...
... To increase strength, Gut modulating, blood pressure lowering, diuretic and sedative (L.) Maton appetite stimulant. activities reported for crude extract of cardamom ; shortened hamster gastrointestinal transit time and increased fecal moisture contents reported for cardamom extract (Huang, Y.L., 2007); gastroprotective effects reported for fruit extract against gastric lesions induced by aspirin, ethanol, and pylorous ligature in rats (Jamal, A., 2006) Zingiber officinale Roscoe To increase digestion, bloating. Gastroprotective effect reported for ginger during ethanol-induced oxidant stress in experimental rats (Prakash, U.N., and Srinivasan, K., 2010); gastroprotective role reported for ginger rhizome extract with two components of the extract, namely cinnamic and gallic acid, respectively, contributing to Helicobacter pylori inhibitory activity and anti-oxidant effects (Nanjundaiah, S.M., 2009); acceleration by ginger of gastric emptying and stimulation of antral contractions in healthy volunteers (Wu, K.L., 2008); reported prokinetic activity of ginger extract along with spasmolytic effects thus validating its use in gastrointestinal disorders ; gastroprotective effects of ginger reported in albino rats for gastric ulcer induced by ulcerogenic agents (Al-Yahya, M.A., 1989); inhibition of gastric lesions induced by HCl/ethanol by ginger and its constituents zingiberene and 6-gingerol (Yamahara, J., 1988). ...
An ethnomedicinal survey was carried out at Station Purbo Para village of Jamalpur Sadar sub-district in Jamalpur district of Bangladesh. Information on 121 medicinal plant species was obtained from the folk medicinal practitioners. All plants were screened in the scientific databases and scientific journals for pharmacological activities or presence of phytochemicals, which could be relevant to their folk medicinal uses. 61 plants (50.4%) of the total were found to have relevant pharmacological activities consistent with their uses. The actual number of relevant plants can increase further for a number of plants used by the folk medicinal practitioners are yet to be studied through relevant scientific experiments. The results suggest that the medicinal plants used by the folk medicinal practitioners of Bangladesh cannot be dismiised as irrelevant; in fact, the present study demonstrates that a substantial percentage of plants should be scientifically studied as soon as possible in a thorough manner for they can be sources of potentially important and efficacious drugs.
... As the gastrointestinal transit has been slightly increased, the movements were not considered responsible for the observed antidiarrhoeal activity. Huang et al. (2007) recently reported pectic polysaccharide rich black cardamom extract (Amomum villosum) shortened gastrointestinal motility and increased fecal moisture contents. Previously the volatile oils from cardamom showed rabbit jejunum contraction on a small doses and relaxation on large doses (El Tahir et al., 1997). ...
Diarrhoea is a major health care problem in developing countries. Elettaria cardamomum Maton fruits, commonly known as cardamom are widely used for flavoring purposes in food. In this study we evaluated the antidiarrhoeal activity of hot water extract of cardamom against experimental diarrhoeal models on mice. Cardamom extract showed significant antidiarrhoeal activity against castor oil and magnesium sulphate induced models. Whereas, the gastrointestinal motility was slightly increased.
... The consumption of polysaccharide fractions obtained from other edible plants such as Zizyphus jujuba, Salvia plebeia, and Amomum villosum has also been reported to increase intestinal motility and to reduce gastrointestinal transit time. 3,23,24 In Table 4, it was demonstrated that the consumption of wild grape WSCC at medium and high doses could lead to a significant (P < 0.05) reduction of cecal ammonia content by 59.3−63.0%. Fecal sample analyses also demonstrated that consumption of wild grape WSCC at three different doses significantly (P < 0.05) reduced the ammonia concentration in fresh feces by 23.2−53.9%, ...
The dose-response relationship of the water-soluble carbohydrate concentrate (WSCC) from wild grape ( Vitis thunbergii Sieb. & Zucc.) on intestinal health was investigated in this study. WSCC contained carbohydrates up to 71.9 g/100 g, including arabinose-rich pectic polysaccharide, hemicelluloses, glucose, and fructose. The consumption of WSCC (0.5 and 1.5 g/100 g of diet) effectively (P < 0.05) shortened gastrointestinal transit time (-62.3 to -63.0%), decreased toxic cecal ammonia (-59.3 to -63.0%) and daily fecal ammonia output (-29.7 to -41.4%), decreased the activities of fecal β-glucuronidase (-78.6%), β-glucosidase (-80.5 to -87.5%), mucinase (-64.6 to -72.7%), and urease (-83.2 to -86.0%), increased fecal moisture content (116-129%), and also increased short-chain fatty acid levels in cecal contents (1.8-3.3-fold). These findings suggested that consumption of wild grape WSCC might diminish the exposure of intestinal mucosa to toxic ammonia and other detrimental compounds and, hence exert, favorable effects on improving gastrointestinal milieu.
Ayurveda is a several millennia old Indian medical system. Data from historical, epidemiological, experimental and clinical studies provide compelling evidence that several ayurvedic neutraceticals, not only provide prophylactic and therapeutic activity against several diseases, but may actually improve general health and promote longevity. These include herbs, oils, spices, plants, minerals and trace amounts of heavy metals. Although widely used in India, firm scientific evidence for their effectiveness has been lacking due to the small and often improperly done clinical trials. However more expansive and rigorous research is now being done, providing evidence based data on the effectiveness and safety of these natural products. In the United States, Ayurvedic medications are regulated as dietary supplements. The first part of this four part series reviews seven popular ayurvedic naturoceuticals or ayurceuticals.
Plants continue to be a major source of medicine, as they have been throughout human history. Plants are the only source of food and energy in our ecosystem. Food itself is a medicine. Food in our diet either enhances or disturbs the potency of the drug consumed. The human body consists of five elements: ether, water, air, fire, and earth. Every ancient medicine system, such as the Indian medicine system Ayurveda, the Chinese medicine Unani, and the Japanese healing system of Reiki, has described it in one way or another. The key to maintaining good physical and mental health is in keeping these five elements in harmonic balance through proper diet, herbs, and lifestyle; otherwise, early aging and various diseases can manifest. In light of the research in progress on the benefits of various phytochemicals in foods, it appears feasible that the naturally occurring chemical compounds in herbs could be helpful in the prevention or treatment of many chronic diseases, including cancer and cardiovascular disease. Although food has been used for a long time to improve health, around 400 BC, Hippocrates said, “Let your food be your medicine, and your medicine be your food.” Now, modern knowledge of health is being used to improve food. In recent years, scientific evidence has revealed that bioactive dietary components benefi t health in ways that extend beyond meeting basic nutritional needs. The food and nutrition science has moved from simply identifying and correcting nutritional defi ciencies to nutraceuticals, foods that promote optimal health and reduce the risk of certain debilitating diseases.
Ripe fruits of Amomum villosum Lour. are important traditional Chinese medicines and food spices. Due to similar morphological and anatomical characteristics, fruits from some Alpinia species are used clinically as substitutes or adulterants of Fructus Amomi. In this study, we determined the nrDNA ITS1 (internal transcribed space 1) sequences from Amomum villosum and ten Alpinia species, which are adulterants of Fructus Amomi. The ITS1 sequences of these species were 175-179 bp in length, and the G+C contents were 53.37-56.74%. Sequence alignment revealed that there were 55 polymorphic nucleotide sites among the tested species. The base substitution were 0.57-9.60% within the ten Aplinia species, but 17.61-21.59% between Amomum villosum and the Alpinia species. These molecular data indicated that ITS1 sequences can be used to differentiate Fructus Amomi and its substitutes or adulterants from various Alpinia species.
The purpose of this study was to investigate the effect of the water-soluble polysaccharide-rich sage weed (Salvia plebeia) extracts on intestinal function. The results showed that the extract is rich in water-soluble polysaccharides (60.5/100 g extract), which are mainly composed of pectic polysaccharides and hemicellulose. The inclusion of sage weed extract in the control diet at a level of 0.5/100 g diet resulted in significantly (P < 0.05) improved effects on intestinal and faecal parameters of the hamsters, such as shortened gastrointestinal transit time, reduced caecal ammonia, decreased daily faecal ammonia output, increased short-chain fatty acid concentrations in caecal content, and lowered activities of β-d-glucuronidase, β-d-glucosidase, mucinase, and urease. These findings suggest that an adequate intake of sage weed extracts (0.5/100 g diet) may play a role in the maintenance of intestinal health by reducing the exposure of intestinal mucosa to toxic materials and other harmful compounds.
The effects of particle size changes by micronization on the intestinal health-promotion ability of orange insoluble fiber fraction (IFF) were investigated in a hamster model by feeding 3 diets, which contained unmicronized IFF (control), jet-milled IFF, and high-pressure micronized IFF as the sole fiber source in diet. The results showed that the micronization treatments significantly altered the physicochemical properties of insoluble fiber. The consumption of the micronized fibers (6.26 to 11.4 microm) at a level of 50 g/kg diet, especially those prepared by high-pressure micronization, resulted in significant (P < 0.05) improvements in cecal and fecal parameters such as reduced cecal ammonia concentration (-37.1%), increased fecal moisture (164%), and decreased activities of beta-D-glucuronidase (-68.3%) and mucinase (-28.5%) in feces. Both the particle size and treatment were important factors affecting the composition and physiological functions of fibers, and the consumption of micronized fiber might exert favorable effects on improving the intestinal health of hamsters. This study might give some hints for the potential applications of micron technology in food industry and provide opportunities to develop new formulations of fiber-rich functional foods.
This study was to investigate the effects of water-soluble carbohydrate concentrate (WSCC) prepared from Chinese jujube ( Zizyphus jujuba) on different intestinal and fecal indices in a hamster model. WSCC contained carbohydrates (771 g kg(-1) of WSCC) including glucose, fructose, pectin polysaccharide, and hemicellulose. The administration of WSCC (5.0 and 15 g kg(-1) of diet) effectively ( P<0.05) shortened gastrointestinal transit time (by 34.2-57.3%), reduced cecal ammonia (by 58.1-60.3%), elevated total short-chain fatty acid concentrations in cecum (3-4-fold), increased fecal moisture (147-170%), reduced daily fecal ammonia output (by 31.9-75.8%), and decreased the activities of beta-D-glucuronidase (by 73.0-73.8%), beta-D-glucosidase (by 58.2-85.7%), mucinase (by 46.2-72.6%), and urease (by 31.9-48.7%) in feces. This study suggested that adequate consumption of jujube WSCC (at least 5.0 g kg(-1) of diet or 40 mg day(-1)) might exert favorable effects on improving the gastrointestinal milieu and reducing the exposure of intestinal mucosa to toxic ammonia and other detrimental compounds.
For sixteen years, the American institute of Nutrition Rodent Diets, AIN-76 and AIN-76A, have been used extensively around the world. Because of numerous nutritional and technical problems encountered with the diet during this period, it was revised. Two new formulations were derived: AIN-93G for growth, pregnancy and lactation, and AIN-93M for adult maintenance. Some major differences in the new formulation of AIN-93G compared with AIN-76A are as follows: 7 g soybean oil/100 g diet was substituted for 5 g corn oil/ 100 g diet to increase the amount of linolenic acid; cornstarch was substituted for sucrose; the amount of phosphorus was reduced to help eliminate the problem of kidney calcification in female rats; L-cystine was substituted for DL-methionine as the amino acid supplement for casein, known to be deficient in the sulfur amino acids; manganese concentration was lowered to one-fifth the amount in the old diet; the amounts of vitamin E, vitamin K and vitamin B-12 were increased; and molybdenum, silicon, fluoride, nickel, boron, lithium and vanadium were added to the mineral mix. For the AIN-93M maintenance diet, the amount of fat was lowered to 40 g/kg diet from 70 g/kg diet, and the amount of casein to 140 g/kg from 200 g/kg in the AIN-93G diet. Because of a better balance of essential nutrients, the AIN-93 diets may prove to be a better choice than AIN-76A for long-term as well as short-term studies with laboratory rodents.
A simple method has been developed for quantitative acetic, propionic, isobutyric, butyric, isovaleric, valeric, isocaproic, and caproic acids in intestinal fluids, feces and blood. The method utilizes extraction with ether and gas chromatography. It is accurate over a wide range of SCFA concentrations and appears to be applicable to any biological fluid.
Mucinase and beta-glucuronidase enable colon bacteria to degrade protective mucins and recycle glucuronide conjugates of toxins and carcinogens. The response of these bacterial enzymes to dietary fiber was studied in the laboratory rat. Fiber-free basal diet was mixed with guar gum, pectin, carrageenan, or cellulose at levels of 5 and 15%. These diets were fed for 21 days to groups of six male Fischer-344 rats having an average weight of 150 g. Mucinase and beta-glucuronidase activities were assayed in fresh rat feces. Rats fed 15% guar gum or pectin gained significantly (P less than 0.05) less weight than the other rats. Mucinase specific activity was highest in the fiber-free diet group and lowest in the 15% guar gum group. Total daily output of mucinase was highest in rats fed fiber-free diet or cellulose and lower in rats fed more readily fermentable fiber. Specific activity and total output of beta-glucuronidase were highest in rats fed fiber-free diet and significantly lower in those fed 15% fiber diets. These data are consistent with the hypothesis that some kinds of dietary fiber may play a role in the etiology of intestinal disease.
Influences of galactosylsucrose and xylosylfructoside on body mass gain, the digestive tract mass and concentrations of organic acids such as acetic, propionic, butyric, lactic and succinic acid in the cecum were compared among rats fed a cholesterol-enriched fiber-free diet [cholesterol 6 + cholic acid 1.5 (g/kg)] containing either galactosylsucrose, xylosylfructoside or sucrose (100 g/kg) or the above fiber-free diet without test sugar (control) for 21 d. Body mass gain was greater in rats fed sucrose, but not in rats fed galactosylsucrose or xylosylfructoside, than in control rats. The mass of the small intestine and colon plus rectum was larger in rats fed xylosylfructoside than in control rats. Cecal contents and cecal tissue mass were heavier, water content of cecal contents was higher, and pH and ammonia concentration of cecal contents were lower in rats fed diets containing xylosylfructoside than in control rats. Galactosylsucrose had similar effects, although not all differences were significant. The concentration of hydrogen ion in cecal contents positively correlated to total cecal concentration of measured organic acids and to amount of cecal contents. Total concentration of measured organic acids in cecal contents positively correlated to cecal tissue mass. The estimated contribution of galactosylsucrose, xylosylfructoside and sucrose for body mass deposition were 0.19, -0.29 and 0.51 (g body mass gained/g sugar), respectively.
The effects of yogurt containing viable Lactobacillus strain GG (L. GG) and/or fiber supplements on fecal enzyme activities (beta-glucuronidase, nitroreductase, beta-glucosidase, glycocholic acid hydrolase, urease) and on bacterial metabolites in urine (phenol, p-cresol) were studied in 64 females, 20-41 y old. The subjects were randomly divided into three groups: the first group received L. GG yogurt (2 x 150 mL/d, containing 10(11) colony-forming units (cfu)/L of L. GG), the second group received L. GG yogurt and a rye fiber product (30 g/d, equivalent to 9 g fiber/d), and the third group received placebo yogurt (pasteurized) and fiber. The supplementation period lasted 4 wk, with a preceding 2-wk baseline period and a 2-wk follow-up period. The mean fecal count of L. GG was approximately 10(6) cfu/g feces during the supplementation, and L. GG persisted in the fecal samples of 28% of the subjects for 2 wk after supplementation. L. GG yogurt alone or with fiber significantly decreased fecal beta-glucuronidase, nitroreductase and glycocholic acid hydrolase activities. These enzyme activities returned to baseline levels during the follow-up period. beta-Glucosidase and urease activities were not altered significantly during the study. The addition of fiber to L. GG and placebo yogurt had no effect on the enzymic activities. Urinary excretion of p-cresol decreased significantly in groups receiving L. GG. These data demonstrate that L. GG can modify the colonic environment with possible health effects.
Mucins play an important protective role in the colonic mucosa. Luminal factors modulating colonic mucus release have been not fully identified.
To determine the effect of some dietary compounds on mucus discharge in rat colon.
An isolated vascularly perfused rat colon model was used. Mucus secretion was induced by a variety of luminal factors administered as a bolus of 1 ml for 30 minutes in the colonic loop. Mucin release was evaluated using a sandwich enzyme linked immunosorbent assay supported by histological analysis.
The three dietary fibres tested in this study (pectin, gum arabic, and cellulose) did not provoke mucus secretion. Luminal administration of sodium alginate (an algal polysaccharide used as a food additive) or ulvan (a sulphated algal polymer) induced a dose dependent increase in mucin discharge over the concentration range 1-25 mg/l (p<0.05 for 25 mg/l alginate and p<0.05 for 10 and 25 mg/l ulvan). Glucuronic acid and galacturonic acid, which are major constituents of a variety of fibres, produced significant mucin secretion (p<0.05). Hydrogen sulphide and mercaptoacetate, two sulphides produced in the colonic lumen by microbial fermentation of sulphated polysaccharides, did not modify mucin secretion. Among the short chain fatty acids, acetate (5-100 mM) induced a dose dependent release of mucus (p<0.05 for 100 mM acetate). Interestingly, butyrate at a concentration of 5 mM produced colonic mucin secretion (p<0.05), but increasing its concentration to 100 mM provoked a gradual decrease in mucus discharge. Propionate (5-100 mM) did not induce mucin release. Several dietary phenolic compounds (quercetin, epicatechin, resveratrol) did not provoke mucus discharge.
Two algal polysaccharides (alginate and ulvan), two uronic acids (glucuronic acid and galacturonic acid), and the short chain fatty acids acetate and butyrate induce mucin secretion in rat colon. Taken together, these data suggest that some food constituents and their fermentation products may regulate the secretory function of colonic goblet cells.
Short chain fatty acids (SCFAs), including acetate, propionate, and butyrate, are produced at high concentration by bacteria in the gut and subsequently released in the bloodstream. Basal acetate concentrations in the blood (about 100 microm) can further increase to millimolar concentrations following alcohol intake. It was known previously that SCFAs can activate leukocytes, particularly neutrophils. In the present work, we have identified two previously orphan G protein-coupled receptors, GPR41 and GPR43, as receptors for SCFAs. Propionate was the most potent agonist for both GPR41 and GPR43. Acetate was more selective for GPR43, whereas butyrate and isobutyrate were more active on GPR41. The two receptors were coupled to inositol 1,4,5-trisphosphate formation, intracellular Ca2+ release, ERK1/2 activation, and inhibition of cAMP accumulation. They exhibited, however, a differential coupling to G proteins; GPR41 coupled exclusively though the Pertussis toxin-sensitive Gi/o family, whereas GPR43 displayed a dual coupling through Gi/o and Pertussis toxin-insensitive Gq protein families. The broad expression profile of GPR41 in a number of tissues does not allow us to infer clear hypotheses regarding its biological functions. In contrast, the highly selective expression of GPR43 in leukocytes, particularly polymorphonuclear cells, suggests a role in the recruitment of these cell populations toward sites of bacterial infection. The pharmacology of GPR43 matches indeed the effects of SCFAs on neutrophils, in terms of intracellular Ca2+ release and chemotaxis. Such a neutrophil-specific SCFA receptor is potentially involved in the development of a variety of diseases characterized by either excessive or inefficient neutrophil recruitment and activation, such as inflammatory bowel diseases or alcoholism-associated immune depression. GPR43 might therefore constitute a target allowing us to modulate immune responses in these pathological situations.
The colonic microflora is of crucial importance to any consideration of the role of dietary fibre in health and disease since many of the physiological effects of fibre on the gut are dependent on, or are influenced by, the activities of the colonic bacteria. This area of interaction between bacteriology and gut physiology is still poorly understood, mainly because of the inaccessibility of the proximal colon.
The effect of dietary fibers on the digestive tract mass, diamine oxidase (DAO) activities in the small intestine and plasma and pool of ammonia and organic acids such as acetic, propionic, butyric, lactic and succinic acid in the cecum in rats fed a liquid formula diet was compared. Rats were fed an elemental liquid diet (ED) or ED containing 3g/100 ml of dietary fiber either a mixture of crystal cellulose and carboxymethyl cellulose sodium salt (CC), sugar-beet pectin (BP) or hydrolyzed xyloglucan (HXG) for 14 days. The mass of colon plus rectum was higher in rats fed CC, but not in rats fed BP and HXG than in rats fed ED. Cecal tissue mass was higher in rats fed BP and HXG, but not in rats fed CC, than in rats fed ED. Cecal contents and cecal pH were higher and lower in rats fed CC, BP and HXG than in rats fed ED. DAO activities in the small intestine and plasma were higher in CC than in rats fed ED. Cecal ammonia were lower in rats fed CC, BP and HXG than in rats fed ED. Production of organic acids was similar between rats fed ED and CC except for acetic acid that was much lower in rats fed CC. Diarrhea and loose feces were also improved in rats fed CC. The results suggest that the addition of a combination of water -soluble and -insoluble dietary fiber to a liquid formula diet would have more beneficial effects on the bowel function than water-soluble dietary fiber alone.
We studied the effect of the particle size of corn brain (CB) on the plasma cholesterol concentration, fecal output, and cecal fermentation. Rats were fed a fiber-free diet (FF) or FF containing CB (50 g/kg diet) of six different particle sizes (500, 350, 250, 177, 149, 105 μm in diameter) for 21 days. The fecal wet weight and wet weight of cecal content were significantly higher in the rats fed CB than in those fed FF. Liver total lipids, fecal moisture, fecal bile acids excretion and moisture of cecal content were significantly lower in the rats fed CB than in those fed FF. As the particle size decreased, the plasma cholesterol concentration, fecal wet weight, and fecal bulking effect decreased, while the liver cholesterol concentration, cecal wall weight, wet weight of cecal content, and total organic acids, acetic acid and n-butyric acid in the cecal content increased.
Juice production from carambola and carrot produces a large quantity of pomace. The pomace contains high levels of insoluble fiber fractions (IFFs) (50.8-56.3 g per 100 g of pomace, dry matter) that have desirable characteristics and physicochemical properties. In this study, the influence of IFFs derived from the pomace was investigated on the intestinal enzymes, fecal bacterial enzymes, and some biochemical parameters in the hamster. Our results showed that feeding carambola and carrot IFFs at 5% of the diet to hamsters significantly (P < .05) reduced cecal pH (6.50-6.64), cecal and fecal ammonia levels (by 18.8%-21.2% and 50.0%-53.7%, respectively), and the activities of β-d-glucosidase (by 12.1%-20.1%), β-d-glucuronidase (by 54.8%-78.2%), mucinase (by 12.6%-20.2%), and urease (by 60.3%-63.7%) in feces. These results suggest that IFFs in carambola and carrot might exert favorable effects on improving intestinal functions and health and could be exploited as functional ingredients in fiber-rich food products.
We compared the effects of different sources of fiber (rye-bran, oat-bran, wheat-bran) and inulin on the activity of fecal bacterial enzymes and concentration of short chain fatty acids (SCFA) in the colonic contents of rats. A diet without fiber was used as a control. The cereal brans and inulin had similar, increasing effect on the activities of β-glucuronidase and urease (P < 0.05). All bran diets also increased β-glucosidase activity while the increase by inulin was non-significant. Concentration of total SCFA was higher in the inulin and rye-bran groups compared to non-fiber and wheat-bran groups (P < 0.05). Concentration of butyrate was higher in rye-bran and inulin groups compared to the non-fiber group (P < 0.05), and that of propionate higher in the inulin group compared to non-fiber and wheat-bran groups (P < 0.05). The SCFA profile in the oat-bran group did not differ significantly from SCFA profile in the other groups. These findings indicate that the source of the fiber does not markedly affect the enzyme activities of the fecal bacterial microbiota, but may cause differences in the profile of SCFA in the rat colon.
Polysaccharides were isolated from the fruits of Limonia acidissima by sequential extraction with water, and 1M and 4M KOH. The water extract contained pectic polymers substituted with side chains comprising mainly of 1,5-, 1,3,5-linked arabinose together with 1,4-, 1,6-, 1,3,6-linked galactose, and lesser amounts of 1,2,4- and 1,3-linked galactose residues. Galactosyl and arabinofuranosyl groups terminated most of the branched residues. The alkaline extracts contained both pectic and hemicellulosic polymers. The insoluble material consists mainly of cellulose-rich material.
The ingestion of dietary fibre has been correlated with the prevention of many health-threatening diseases and cancers. Plant cell walls are the major source of dietary fibre and this review investigates the relationship between the structure of different types of plant cell walls and their beneficial effects. The effects of processing and cooking on dietary fibre are also examined. Structure–function relationships between individual cell wall components and the beneficial effects of dietary fibre are not well defined and it may be that the physical, physiochemical and topochemical properties of plant cell walls and their components are also important.
Passion fruit, a popular tropical fruit, produces a large quantity of edible seeds as agricultural byproducts after juice extraction. The defatted passion fruit seed (PFS) contained a high level of insoluble fibre (∼90%, w/w) of desirable characteristics and physicochemical properties. Cellulose, pectic substances and hemicellulose were the major structural polysaccharides of the PFS insoluble fibre. In this study, the influence of the PFS insoluble fibre on the activities of ileum mucosal enzymes and colonic bacterial enzymes was investigated. It was found that the incorporation of the PFS insoluble fibre into a fibre-free diet at 5% level significantly (p < 0.05) enhanced the intestinal amylase activity (137%), reduced the caecal pH (6.22), decreased the caecal ammonia content (−38.6%) and faecal ammonia output (−21.2%), and also decreased the activities of β-D-glucosidase (−37.4%), β-D-glucuronidase (−52.9%), mucinase (−35.5%) and urease (−91.4%) in faeces. Our results suggested that PFS insoluble fibre might exert favourable effects on intestinal health. The fact that PFS insoluble fibre was more effective than cellulose in improving intestinal health suggested it could be exploited as a new functional ingredient to promote intestinal function and health. Copyright © 2005 Society of Chemical Industry
Five Yorkshire castrates fitted with a post valve T-caecum (PVTC) cannula were used in a 5×5 Latin square design to study the influence of non-starch polysaccharides (NSP) in cereal based diets on site and extent of digestion and gut environment. The cereal part of the control diet was designed to resemble a Swedish slaughter pig feed. Diets H and Hi had a high total NSP content, and by starch dilution, the resulting diets L and Li had a low total NSP content. The insoluble proportion (i) of the total NSP was higher in diets Hi and Li than in the other diets. There was a linear decrease (P<0.05) in both ileal and total tract digestibility of organic matter (OM), crude protein (CP) and energy with increasing dietary NSP content. NSP solubility had no effect (P>0.05) on ileal digestibility of nutrients or dietary fibre (DF) components. The total tract digestibility of OM, fat and energy, and of all DF components was increased (P<0.05) with higher levels of soluble NSP. The total organic acid content and pH in ileal digesta were linearly related (R2=0.90). Diets L and Li showed a higher (P<0.05) proportion of acetic acid in ileal digesta compared to diets H and Hi.
A fiber-free diet supplemented with cellulose, Nori, or Wakame as the principal source of dietary fiber was fed to rats for 12 days, and the cecal bacterial activities (β-glucuronidase, β-glucosidase, azoreductase, nitroreductase and nitrate reductase) were measured. The intake of seaweeds did not affect body weight gain nor food intake; however, algae in the diet was associated with a significant increase on cecal, fresh stool and dry stool weight. All bacterial enzyme activities were lower in the two seaweed groups than the cellulose fed group with exception the of β-glucosidase which was significantly lower in rats fed Wakame. Adaptation to diets containing Nori or Wakame was associated with changes in microbial activity that involved a decrease on reductive and hydrolytic enzymatic activities implicated in the conversion of procarcinogens into carcinogens. The combination of the effect on the gut flora and a more rapid transit of feces would be expected to reduce exposure to potential carcinogens and may have health implications for human nutrition.
Raw passion fruit (Passiflora edulis) seed is rich in crude lipid (24.5 g/100 g) and insoluble dietary fibre (64.1 g/100 g). After defatting, the insoluble fibre-rich fractions (FRFs), including insoluble dietary fibre, alcohol-insoluble solids and water-insoluble solids (84.9–93.3 g/100 g) became the predominant component in the (defatted) seed, and were mainly composed of cellulose, pectic substances and hemicellulose. These insoluble FRFs had water- and oil-holding capacities comparable with those of cellulose, while their bulk densities and cation-exchange capacities were significantly (P<0.05) higher than those of cellulose. All FRFs exhibited significant (P<0.05) effects in absorbing glucose and retarding amylase activity, and might help control postprandial serum glucose. These results underline the value of consumption of these FRFs as fibre sources or low calorie bulk ingredients in food applications. Further investigations on the in-vivo hypoglycemic effect and other physiological properties of these FRFs, using animal feeding experiments, are underway.
A complete chemical characterisation of Aloe vera plant (Aloe barbadensis Miller) was carried out from the dissection of the plant whole leaves in filets and skin. In addition, a mucilaginous gel extracted from the filets was also characterised. Extraction with ethanol of lyophilised Aloe fractions (AIRs) allowed to concentrate the major fraction composed of carbohydrates up to 80%. The composition of the main type of polysaccharides present in the Aloe AIRs was determined. Mannose and cellulosic glucose were the major polysaccharide components in all AIRs, significant amounts of pectic polysaccharides were also detected. Sequential extraction of polysaccharides present in Aloe vera plant portions, revealed that two main types of mannose-containing polymers were present in the Aloe vera plant. The polysaccharide detected in the filet and in the gel fractions corresponded to a storage polysaccharide located within the protoplast of the parenchymatous cells. Its structural and compositional features corresponded to the active polysaccharide known as acemannan. On the contrary, in the skin tissue, the mannosyl residues arose from a structural polysaccharide located within the cell wall matrix. Structural and compositional differences between both polymers were confirmed by methylation analysis. The fact that acemannan is a reserve polysaccharide might help to explain most of the compositional variations reported in the literature for Aloe vera carbohydrates. Further, sequential extraction allowed us to identify several pectic polysaccharides, rich in uronic acids, with a composition similar to that of several antitumoral polymers found in different plant tissues.
With the objective of restoring the low zinc bioavailability of phytate-containing diets, cellulose was replaced by pectin, alginic acid, carrageenan, chitosan or raw potato starch (RS), in phytate-free and phytate-containing diets, and given to rats for 21 days. Feeding chitosan, alginic acid or RS (200 g/kg) as the dietary fiber polysaccharide lessened the deleterious effect of phytate, increasing zinc apparent absorption (excluding RS), femur zinc concentration and growth, compared to rats fed cellulose or fiber-free diets. Feeding pectin, alginic acid, chitosan or RS (200 g/kg) lowered cecal pH and increased cecal content weight. Chitosan, alginic acid and RS increased femur zinc concentration when fed to rats in phytate-containing diets, while RS was also effective in phytate-free diets. Therefore, chitosan and alginic acid might enhance zinc bioavailability through a different mechanism from that of RS. Feeding chitosan, alginic acid or raw potato starch lessens the inhibitory effect of phytic acid on zinc bioavailability.
We studied the effect of diet on the activities of four enzymes found in the intestinal flora of the male F344 rat. Animals initially fed a diet with high vegetable and grain content were shifted to a diet consisting predominantly of beef. While eating the meat diet, the rats had significantly higher levels of nitroreductase, azoreductase, and beta-glucuronidase in their fecal flora when compared to levels measured during grain feeding. However, beta-glucosidase activity was significantly lower during meat feeding, which probably reflected the lack of beta-glucosidic linkages in this diet. These findings suggested that a high-beef diet, similar in composition to that consumed by humans with a relatively high risk of colon cancer, is associated with elevated levels of specific enzymes in the colon microflora. These enzymes have been implicated in the conversion of procarcinogens into carcinogens.
To determine whether the route and/or composition of nutritional support alters intestinal barrier function (measured as bacterial translocation), rats were divided into three groups: food (controls), intravenous total parenteral nutrition (IV-TPN) fed, and oral total parenteral nutrition (ORAL-TPN) fed. Bacterial translocation did not occur in the rats that were fed normally, but did occur in 60% of the rats fed the IV-TPN or the ORAL-TPN diets for 7 days (p less than 0.05). Since both the IV-TPN and ORAL-TPN diets induced bacterial translocation and the TPN solution (28% glucose and 4.5% amino acids) lacks fiber, two additional groups of rats were fed orally 2.5 gm cellulose powder/day plus TPN solution by either the intravenous or the oral route. The addition of cellulose powder decreased the incidence of bacterial translocation to 8% in the group fed the ORAL-TPN diet and to 0% in the group fed the IV-TPN diet. Cellulose improved intestinal barrier function, even though it did not prevent bacterial overgrowth or the loss of mucosal mass in the rats fed the IV-TPN or ORAL-TPN diets. Cellulose powder appears to have prevented bacterial translocation primarily by preventing IV-TPN- or ORAL-TPN-induced alterations in mucosal structure. Thus the oral administration of this fiber maintains intestinal barrier function and prevents bacterial translocation even in the absence of oral nutrients.
Since it has been demonstrated that a high level of fat is a dietary factor in the etiology of colon cancer, the effect of carrageenan, a polysaccharide extracted from the red seaweeds, on 1,2-dimethylhydrazine-induced colonic tumors in rats fed a semipurified control diet containing an ordinary level of fat was studied. Nevertheless, the enhancing effect of carrageenan on colonic tumors was observed. The rats fed a carrageenan diet had approximately twice the fecal weight compared to the rats fed a control diet. While no significant differences were found in beta-glucuronidase activities in colonic mucosa, liver or plasma in the carrageenan-fed rats and controls, the activity in feces was significantly lower in the carrageenan-fed rats. At least, no beta-glucuronidase activity seemed to be related to the tumor-enhancing effect of carrageenan.
The effects of propionate on serum and liver lipid concentrations were studied in cholesterol-fed rats. Both serum and liver cholesterol levels were significantly lower in rats fed the cholesterol-propionate diet than in rats fed the cholesterol diet without propionate. Liver triglyceride levels were also significantly lower in the propionate-treated group. Serum triglyceride concentrations were not influenced by the propionate feeding. Propionate intake was not associated with histologic changes in liver tissue. This study indicates that 0.5% sodium propionate-supplemented diets slightly but significantly reduced cholesterol accumulation in both serum and liver of cholesterol-fed rats. Thus propionate, a metabolic product of fiber fermentation, may mediate some of the hypocholesterolemic effects of certain soluble plant fibers.
1. This study examines the effect of propionate, normally produced in the gut, on lipid metabolism of resident macrophage. This cell is very abundant in the epithelial lining of the gut. 2. The activity of propionyl-CoA synthetase in macrophages was shown to be 0.39 nmol/min per mg protein, so this cell presents the ability to use propionate. Propionate at concentrations varying from 0.5 to 5 mM did not affect the activities of carnitine acetyltransferase, ATP-citrate lyase, acetoacetyl-CoA thiolase and 3-oxoacid-CoA transferase. 3. Thus this short chain fatty acid did not alter the capacity for transferring acetyl-CoA from mitochondria to cytosol and for ketone bodies formation and oxidation. However, propionate (40 mM) inhibited the incorporation of [1-14C]-palmitate into phospholipids, cholesterol, cholesterol ester and triacylglycerol and the incorporation of [3-14C]-pyruvate into phospholipids. 4. These findings suggest that fibre-rich diet by generating propionate may regulate macrophage lipid metabolism.
1. This work examines some in vivo and in vitro pharmacologic and toxicologic effects of extracts of Rhazya stricta, a medicinal plant in the United Arab Emirates. 2. R. stricta extracts at doses of 0.1-10 mg reduced the mean arterial blood pressure (MBP) of anesthetized rats in a dose-dependent manner. The depressor effect was partially sensitive to atropine (5 microM). Although the MBP was reduced by 50% by both doses of extracts, the normal electrocardiogram pattern and the heart rate remained unaltered. 3. Acute treatment of rats with the lyophilized extract at doses of 4 g/kg produced a significant rise in insulin concentration. In streptozotocin-diabetic rats loaded orally with glucose (1 g/kg), R. stricta at doses of 8 g/kg produced significant decreases in plasma glucose concentration at 0.5 and 1 h after treatment. 4. Chronic treatment of rats and mice for 28 days with the lyophilized extract of R. stricta did not affect the plasma glucose or insulin concentration or any of the hematological or biochemical indices measured. 5. The extracts of R. stricta (0.5-4 g/kg) dose-dependently decreased the gastrointestinal transit time in mice by 4-50%. 6. The butanolic extract of R. stricta (1 and 2 g/kg) significantly reduced the carrageenan-induced increase in raw paw edema 3 and 4 h after the extract administration. 7. The rectal temperatures of normothermic and pyrexic rats were reduced significantly 0.5 and 1 h after administration of butanolic R. stricta at doses of 1 and 2 g/kg. 8. The butanolic extract of R. stricta at doses of 1 and 2 g/kg significantly increased the reaction time on the hot plate 30 and 60 min after administration to rats. 9. At concentration < 0.05 mg/ml (bath concentration), lyophilized water and butanol extracts of R. stricta potentiated the twitch responses induced by indirect electrical stimulation in the rat phrenic nerve diaphragm preparation. The responses were inhibited by concentrations > 0.05 mg/ml. Neostigmine (2 x 10(-4)M) did not alter these effects of the extracts. 10. R. stricta extracts dose-dependently decreased the force of contraction and heart rate of the isolated rabbit heart. Atropine (1 x 10(-5)M) had no effect on the inhibitory activity of these extracts. The lyophilized water extract (> 10 mg) and butanol extract (> 5 mg) produced irreversible inhibition and disturbances in the force of contraction and heart rate.
Three studies were done to determine the effect of feeding diets containing high levels of a readily fermentable carbohydrate (lactose in milk or yogurt, or pure lactose) or an undigestible, unfermentable diluent (alpha-cellulose) on urease (EC 3.5.1.5) activity and net ammonia production in the rat gastrointestinal (GI) contents. Rats (170-200 g) were fed a control diet or diets containing 55% dried milk or 55% dried yogurt, 25% lactose or 10% alpha-cellulose. Feeding diets containing milk or yogurt decreased urease activity to approximately 11% of the control value in the small intestine (on the basis of grams of collected contents or total contents), and to 50% in the large intestine (only on the basis of grams of collected contents). Feeding the diet containing 25% lactose also decreased urease activity (on the basis of grams of collected contents or total contents) to about 20% of the control value in the small intestine, but not (P > 0.05) in the large intestine. Net ammonia production rate was correlated (r2 = 0.98) with urease activity in the large intestinal contents, and the rate of ammonia production from ureolysis represented about two thirds of the total. Feeding the cellulose diet decreased (P < 0.05) both urease activity and net ammonia production in the large intestine to approximately 30% of the control value. Weights of tissue and contents of the large intestine were much higher (P < 0.01) in rats fed diets containing milk products or lactose than in the control rats, but were not affected by consumption of the cellulose diet. Results of our studies indicate that feeding diets containing high levels of milk products (lactose) or cellulose reduces urease activity and net ammonia production in the rat intestine, and thus may be beneficial for improving animal and human health.
Four-week-old rats were fed on diets containing either no dietary fiber (DF) or a DF source (WSSF, ISF or cellulose) for 4 weeks. The DF level was adjusted to 5%. The WSSF diet contained 3% and 2%, respectively, of WSSF and cellulose. No rat in any group experienced diarrhea, and none of the experimental diets suppressed the growth of rats, the apparent absorption of major nutrients being almost 100%. However, the rate of degradation of DF during the digestive process was significantly different (p < 0.05, cellulose, 23.6%; WSSF with cellulose, 64.5% (WSSF degradation only was 91.8%); and ISF, 77.6%). The plasma and liver lipid levels were within normal ranges, although the liver cholesterol level in those rats fed on WSSF and ISF was significantly lower (p < 0.05) than in those fed on cellulose. The cecal organic acid contents were in the order of WSSF > ISF > cellulose > DF-free. Furthermore, WSSF was effective in shortening the gastrointestinal transit time. The results indicate that WSSF seems to have favorable effects on the intestinal functions.
We have investigated the effects of methanolic and alcoholic extracts from Amomi Semen on gastric secretion, as well as gastrointestinal propulsion or the prokinetic activities. The methanolic extract from Amomi Semen dose dependently decreased the volume output, acid output, and pepsin output in rat's gastric juice with increasing pH value, while the alcoholic extract had no influence on basal gastric acid secretion. Furthermore, the alcoholic extract improved the L-dopa to induce a delay of gastrointestinal transit in mice, while the methanolic extract did not improve it. However, both extracts had no influence on gastrointestinal transit in intact mice. These results suggest that Amomi Semen has an inhibitory effect on gastric acid secretion and that it has effects as the gastrointestinal prokinetics rather than propulsion. The present study pharmacologically elucidates a belief that Amomi Semen has been used in Chinese medicine for the treatment of gastrointestinal dyspepsia, which includes hyperchlorhydria, stomachache, abdominal distention, anorexia, gastric atony, etc.
To evaluate the effect of apple components on cecal fermentations and lipid metabolism, rats were fed diets containing 5 g/100 g apple pectin (PEC), 10 g/100 g high polyphenol freeze-dried apple (PL) or both (PEC + PL). The cecal pH was slightly acidic (6.49) only in rats fed the PEC + PL diet (controls, 7.02). The cecal short-chain fatty acid pool was enlarged by all the apple fractions, with a peak of 560 micromol in rats fed the PEC + PL diet compared with 189 micromol in controls. Butyrate concentrations were 2-fold greater in rats fed the PL diet than in controls. Substantial concentrations of galacturonate and succinate (approximately 40 mmol/L) were found in the cecum of rats fed the PEC diet and, to a lesser extent, the PEC + PL diet. The PEC + PL diet significantly lowered plasma cholesterol, whereas both the PL and PEC + PL diets lowered plasma triglycerides. Liver cholesterol and triglyceride concentrations were lower in rats fed the PEC and PEC + PL diets. Fecal bile acid excretion was markedly reduced, whereas sterol excretion was significantly increased by dietary PEC. Rats fed the PEC and PEC + PL diets also had lower apparent cholesterol absorption than controls (30 compared with 43%). In conclusion, apple pectin and the polyphenol-rich fraction were more effective when fed combined together than when fed separately on large intestine fermentations and lipid metabolism, suggesting interactions between fibers and polyphenols of apple.
It is often assumed that fruits and vegetables contribute to protect against degenerative pathologies such as cardiovascular diseases. Besides epidemiological observations, scientific evidences for their mechanism of action are scarce. In the present study, we investigated the mean term and post-prandial effects of lettuce ingestion on lipid metabolism and antioxidant protection in the rat.
Feeding rats a 20% lettuce diet for 3 weeks resulted in a decrease cholesterol LDL/HDL ratio and a marked decrease of liver cholesterol levels (-41%). Concurrently, fecal total steroid excretion increased (+44%) and apparent absorption of dietary cholesterol was significantly depressed (-37%) by the lettuce diet. Lettuce diet also displayed an improvement of vitamin E/TG ratio in plasma and limited lipid peroxidation in heart as evidenced by TBARS. In post-prandial experiment, lettuce intake significantly increased both ascorbic acid and alpha-tocopherol plasma levels which contribute to improve plasma antioxidant capacity within 2 h of consumption. Other lipid-soluble antioxidants (lutein and vitamin E) may also improve the plasma antioxidant capacity.
Lettuce consumption increases the total cholesterol end-products excretion and improves antioxidant status due to the richness in antioxidants (vitamins C, E and carotenoids). In our model, lettuce clearly shows a beneficial effect on lipid metabolism and on tissue oxidation. Therefore regular consumption of lettuce should contribute to improve protection against cardiovascular diseases.
Short-chain fatty acids (SCFAs) accelerate colonic transit. This study examined whether this action was mediated by activation of the peristaltic reflex. SCFAs (acetate, butyrate, or propionate) were applied to the central compartment of a three-compartment flat-sheet preparation of the rat middle to distal colon. The release of serotonin (5-HT), brain-derived neurotrophic factor (BDNF), and CGRP was measured in all three compartments. Ascending contraction and descending relaxation were measured in the orad and caudad compartments. The addition of SCFAs at physiological to supraphysiological concentrations (0.5-100 mM) to the central compartment elicited concentration-dependent ascending contraction and descending relaxation (EC50 approximately 5 mM). At this concentration, SCFAs induced an 8- to 11-fold increase in 5-HT release and a 2- to 3-fold increase in CGRP release in the central compartment only. They had no effect on BDNF release. CGRP release was inhibited by a 5-HT4 but not a 5-HT3 receptor antagonist. Ascending contraction and descending relaxation were also inhibited by 5-HT4 and by CGRP receptor antagonists added to the central compartment. 5-HT and CGRP release, as well as ascending contraction and descending relaxation induced by mechanical stimulation of the mucosa (2-8 strokes), were significantly augmented by 1 mM acetate. Acetate (1 mM) also doubled propulsive velocity in isolated whole segments of the guinea pig colon. In conclusion, chemical stimulation of the mucosa by SCFAs triggers a peristaltic reflex mediated by the release of 5-HT from mucosal cells and activation of 5-HT4 receptors on sensory CGRP-containing nerve terminals. This SCFA-induced peristaltic pathway augments the peristaltic reflex elicited by mechanical stimulation of the mucosa.