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1.
This study was conducted to investigate the inhibitory effects of palatinose and Palatinit, which are disaccharides (or disaccharide alcohol) connected through an alpha-1,6-glucosyl linkage, on the hydrolysis of other carbohydrates, using an enzyme extract from the rat small intestine and a purified sucrase-isomaltase complex. Palatinose and its hydrogenated product, Palatinit, an equimolar mixture of alpha-O-D-glucopyranosyl-1,6-D-sorbitol (GPS) and alpha-O-D-glucopyranosyl-1,6-D-mannitol (GPM), inhibited the hydrolysis of sucrose and maltose. Palatinose and Palatinit also inhibited the hydrolysis of dextrin and soluble starch. Kinetic analysis of the enzymatic inhibition by GPS and GPM on sucrose hydrolysis revealed that both GPS and GPM competitively inhibit sucrase catalytic activity. These results suggest that disaccharides with an alpha-1,6-glucosyl linkage competitively inhibit intestinal alpha-glucosidases and may reduce the rate of hydrolysis of sucrose and other alpha-glucosylsaccharides.  相似文献   

2.
A highly soluble quercetin glycoside, alphaG-rutin, is a glucose adduct of insoluble rutin. We examined the effects of difructose anhydride III (DFAIII; di-D-fructofuranosyl 1,2':2,3'-dianhydride) on intestinal absorption of alphaG-rutin by rat experiments. alphaG-rutin, rutin, quercetin, and the quercetin conjugate appeared in the portal blood after an intubation of alphaG-rutin (100 micromol), DFAIII effected higher portal concentrations of alphaG-rutin in portal cannulated rats. In ligated jejunal and ileal loops of rats, alphaG-rutin, rutin, quercetin, and the quercetin conjugate appeared in the intestinal mesenteric blood at both 30 and 60 min in both loops; the concentration of alphaG-rutin was 1.5-3 times higher when absorbed in the presence DFAIII. In the isolated mucosae of the jejunum and ileum, mucosal-to-serosal passage of alphaG-rutin increased with the addition of 100 micromol of DFAIII. These results indicate that alphaG-rutin is absorbed as the intact form and that DFAIII stimulates its absorption in the small intestine.  相似文献   

3.
The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts anti-hyperglycemic effects in rats by inhibiting maltase activity and that these effects are at least partially exerted by its sweet elements, triterpene glycosides.  相似文献   

4.
Epilactose (4-O-beta-galactopyranosyl-D-mannnose) is a rare disaccharide in cow milk that can be synthesized from lactose by the cellobiose 2-epimerase of Ruminococcus albus. In this study, we examined the biological activities of epilactose using male Wistar-ST rats. The apparent rates of calcium and magnesium absorption of rats fed epilactose and fructooligosaccharide diets were greater than those fed control and lactose diets, accompanied by greater weight gain of the cecal wall and higher levels of short-chain fatty acids and other organic acids. Epilactose also increased the calcium absorption in everted small intestinal sacs. In addition, the levels of plasma total cholesterol and nonhigh-density lipoprotein cholesterol were lower in epilactose-fed rats. These results indicate that epilactose promotes calcium absorption in the small intestine and possibly lowers the risk of arteriosclerosis. Cecal microbes may efficiently utilize epilactose and contribute to these biological activities.  相似文献   

5.
A series of crocetin glycosides (crocins) are the main pigment of the stigmas of saffron (Crocussativus L.) and the fruits of gardenia (Gardenia jasminoides Ellis). Although numerous studies have demonstrated that crocetin and crocins have a variety of biological functions, the metabolism of dietary crocetin and crocins remains unknown. In the present study, we investigated the intestinal absorption of orally administered crocetin and crocins in mice. Orally administered crocetin was rapidly absorbed into the blood circulation and was present in plasma as an intact free form and as glucuronide conjugates (crocetin-monoglucuronide and -diglucuronide). Crocetin and its glucuronide conjugates were also found in crocins-administered mouse plasma, whereas intact crocins (glycoside forms) were not detected. These results indicate that orally administered crocins are hydrolyzed to crocetin before or during intestinal absorption, and absorbed crocetin is partly metabolized to mono- and diglucuronide conjugates.  相似文献   

6.
The scope of this study was to determine the ability of flaxseed (Linum usitatissimum L.) proteins to release angiotensin I-converting enzyme inhibitory (ACEI) peptides during simulated gastrointestinal (GI) digestion using a static (SM; no absorption in the intestinal phase) and a dynamic model (DM; simultaneous absorption of digested products in the intestinal phase via passive diffusion). Gastric and gastric + small intestinal digests of flaxseed proteins of both models possessed ACEI activity. The ACEI activity of the gastric + small intestinal digest in the DM (IC(50) unabsorbed, 0.05 mg N/mL; IC(50) absorbed, 0.04 mg N/mL) was significantly higher (p < 0.05) than that of the SM (IC(50), 0.39 mg N/mL). Two peptides, a pentapeptide (Trp-Asn-Ile/Leu-Asn-Ala) and a hexapeptide (Asn-Ile/Leu-Asp-Thr-Asp-Ile/Leu), were identified in the most active ACEI fraction (0.5-1 kDa) of the absorbable flaxseed protein digest by de novo sequencing.  相似文献   

7.
Nonenzymic browning reactions in commercial infant formulas were evaluated through their furosine content as well as the isomeric disaccharides formed during processing. Lactulose was observed only in samples containing appreciable amounts of lactose, whereas maltulose was present in all samples due to the isomerization of maltose. Because formation of maltulose depends on the initial amount of maltose present, the ratio maltose/maltulose was used for comparative purposes. The ratio maltose/maltulose varied within a wide range, 27-167; therefore, low values in maltose/maltulose ratio may indicate severe processing conditions during manufacture, whereas high values may indicate mild processing conditions. Variable amounts of furosine content in samples with similar maltose/maltulose ratios may be attributed to different conditions used during storage. Levels of furosine higher than those reported for milk powder were detected in most studied samples. Determination of both furosine and maltose/maltulose ratio would yield information retrospectively about the heat treatment applied during processing and the storage conditions of commercial infant formula.  相似文献   

8.
The aim of this study is to illustrate the in vivo and in vitro absorption of theasinensins B and A that are (-)-epigallocatechin-3-O-gallate (EGCG)-(-)-epigallocatechin (EGC) dimer and EGCG dimer, respectively, and their transport pathway across the intestinal membrane. Our animal study by a single oral administration to rats demonstrated the intact absorption of theasinensins into the blood system, which was estimated to be a >10-fold lower absorption amount than EGCG. The in vitro absorption study indicated that theasinensins can be transported across Caco-2 cell monolayers, while their permeability coefficients were also >10-fold lower than those of EGCG and EGC. Transport experiments using cytochalasin D or quercetin as a tight junction (TJ) modulator and a non-saturable permeation revealed that theasinensins were transported across Caco-2 cells in a TJ paracellular diffusion route. In conclusion, the dimers of condensed catechins, theasinensins B and A, can be absorbed intact into rat blood and transported across Caco-2 cell monolayers probably through a TJ paracellular pathway.  相似文献   

9.
雏鸡对~3H-维生素A的吸收及其在体内的分布   总被引：3，自引：0，他引：3  
蔡辉益  张姝 《核农学报》1992,6(3):169-173
选用出壳后12时龄的Arbor Acres肉雏鸡165只,用放射性同位素~3H示踪法进行了~3H二维生素A(~3H—V_A)的吸收利用试验。结果表明,1—3日龄的雏鸡对V_A吸收较快,且主要集中在摄食后的2—4小时内进行,5日龄后的雏鸡对V_A的吸收速度减慢;V_A在肠道申的吸收是一个持续过程,约为24—72小时;1周龄的雏鸡对各种不同形态外源V_A的利用率分别为:乳化剂89.43％,微囊型粉剂82.91％,油剂80.67％,对乳化剂V_A利用最佳。  相似文献   

10.
Metabolism of theanine, gamma-glutamylethylamide, in rats   总被引：8，自引：0，他引：8  
The metabolism of theanine, one of the major amino acid components in tea (Camellia sinensis), was studied in rats. High-performance liquid chromatography (HPLC) with fluorometric detection was used to evaluate the nature of theanine's metabolites in plasma, urine, and tissues. In the urine samples collected after administration of 100, 200, and 400 mg each of theanine, intact theanine, L-glutamic acid, and ethylamine, these compounds were detected in a dose-dependent manner. When 200 mg of theanine was orally administered to rats, the plasma concentrations of theanine and ethylamine reached their highest levels about 0.5 and 2 h after administration, respectively. It seems most likely that the enzymatic hydrolysis of theanine to glutamic acid and ethylamine was accomplished in the kidney. These results indicate that orally administered theanine is absorbed through the intestinal tract and hydrolyzed to glutamic acid and ethylamine in the rat kidney.  相似文献   

11.
Previous studies on the transport and absorption of resveratrol (3,5,4-O-trihydroxystilbene) were done using the pure compound. In this study, the absorption of resveratrol in digested peanut micellar from boiled and roasted peanuts was investigated using a human intestinal Caco-2 cell monolayer. The amount transported and rate of transport of both resveratrol glycosides and its hydrolytic product were quantified by a reverse-phase high-performance liquid chromatography method with mass spectrometric detection. Four peaks were identified in the digested peanut micellar of both boiled and roasted peanuts: two resveratrol glycosides, one resveratrol diglycoside, and possibly an acylated resveratrol glycoside. Resveratrol from roasted peanut micellar had a higher transport rate than those from the boiled peanut. This implies that resveratrol from roasted peanut is better absorbed than from boiled peanut. Also, the rate of transport and amount of resveratrol transported were higher for the hydrolytic product than the nonhydrolyzed glycosides. This has strong implications for in vivo absorption as the enzymatic activity of gut microflora could enhance the bioavailability of β-glycosides of dietary polyphenols.  相似文献   

12.
Absorption of orally administered chlorogenic acid (5-caffeoylquinic acid) and caffeic acid in rats was studied to obtain plasma pharmacokinetic profiles of their metabolites. Rats were administered 700 micromol/kg body weight of chlorogenic or caffeic acid, and blood was collected from the tail for 6 h after administration. Ingested caffeic acid was absorbed from the alimentary tract and was present in the rat blood circulation in the form of various metabolites. On the other hand, only traces of metabolites, supposedly caffeic and ferulic acids conjugates, were detected in rat plasma for 6 h after chlorogenic acid administration. Chlorogenic acid and small amounts of caffeic acid were found in the small intestine for 6 h after chlorogenic acid administration. These results suggest that chlorogenic acid is not well absorbed from the digestive tract, unlike caffeic acid, and subject to almost no structural changes to the easily absorbed forms.  相似文献   

13.
Polished and cargo rice, wild rice, rice bran, corn bran, and wheat bran were subjected to a static in vitro digestion model, to monitor changes in their steryl ferulate content and composition. Free sterols, possible hydrolysis products of steryl ferulates, were also measured. Additionally, steryl ferulate bioaccessibility was calculated as the percentage of steryl ferulates liberated from the grain matrix into the digestive juice. Steryl ferulate content ranged between 6.1 and 3900 μg/g and decreased by 1-63% due to digestion. A parallel increase in free sterols of more than 70% was observed in all samples. Additionally, bioaccessibility of steryl ferulates was found to be almost negligible. These findings suggest that intestinal enzymes immediately hydrolyze steryl ferulates, which are liberated from the grain matrix, and thus they are practically unavailable for absorption in the small intestine. This further indicates that the hydrolysis products of steryl ferulates could be bioactive in the gut.  相似文献   

14.
A modification of the official selective absorption method for honey carbohydrates, 31.124--31.133, was studied collaboratively; the determinations of sucrose, total monosaccharides, disaccharides, and higher sugars by this procedure were satisfactory and were adopted by the AOAC. High pressure liquid chromatography of glucose, fructose, and sucrose in honey showed better precision than the modified official method and gave concordant results; it was also adopted. Two methods for hydroxymethylfurfural do not qualify. A method for proline was also adopted.  相似文献   

15.
The metabolic fate of purified glucoraphanin in F344 rats   总被引：1，自引：0，他引：1  
Dietary broccoli is commonly eaten cooked, exposing individuals to intact glucoraphanin rather than to its hydrolysis product, the anticarcinogenic isothiocyanate sulforaphane, since cooking destroys the hydrolyzing enzyme myrosinase. There is little information on the absorption and metabolism of glucoraphanin, due partly to the lack of purified compound. In this study, glucoraphanin was purified from broccoli seed and 150 mumol/kg was administered to male F344 rats. Glucoraphanin (5% of an oral dose) was recovered intact in urine, showing that it is absorbed intact, and no glucoraphanin or metabolites were found in feces. Total urinary products accounted for 20 and 45% of oral and intraperitonneal doses, respectively, including sulforaphane N-acetyl cysteine conjugate (12.5 and 2%), free sulforaphane (0.65 and 0.77%), sulforaphane nitrile (2 and 1.4%), and erucin (0.1 and 0.1%), respectively. Both glucoraphanin and its reduced form glucoerucin were identified in bile following intravenous glucoraphanin administration. We conclude that orally administered glucoraphanin is absorbed intact, undergoes enterohepatic circulation, and is hydrolyzed in the gut in F344 rats.  相似文献   

16.
Hens were immunized on thighs by using whole cells of Streptococcus mutans MT8148 serotype c strain as antigen through intramuscular (im) and subcutaneous (sc) routes to investigate the difference of immunization reactions and the changes in yolk antibody activities against antigen after initial immunization. Several properties of crude IgY were examined to evaluate the stability during food processing. Results showed that the specificity of IgY of im treated hens was nearly 10 times as high as those of sc treated antibody. IgY from the hens immunized with the serotype c strain showed significant cross-reactions against serotypes e and f, while minor reactions against serotypes a, b, d, and g were observed. In thermal stability tests, IgY activity in both yolk and crude IgY decreased with the increasing temperature, from 70 to 80 degrees C, but the thermal denaturation rates between those two samples were not significantly different. The addition of high levels sucrose, maltose, glycerol, or 2% glycine displayed effective protection against thermal denaturation of IgY. Lyophilized yolk-5% gum arabic powder showed better stability against proteases.  相似文献   

17.
Three disaccharides were isolated and purified from a commercial total invert sugar (TIS). The structures of these compounds were determined by a combination of acid and enzymatic hydrolysis studies, chromatographic comparison to standards, and nuclear magnetic resonance spectroscopy. These carbohydrates were identified as O-alpha-D-glucopyranosyl-(1-->3)-D-fructose (IS1), O-beta-D-fructofuranosyl-(2-->6)-D-glucose (IS2), and O-alpha-D-glucopyranosyl-beta-D-glucopyranoside (IS3). On the basis of these structures a mechanism for the hydrochloric acid catalyzed hydrolysis of sucrose is proposed: protonation of the glycosidic oxygen of sucrose leading to the formation of glucopyranosyl and fructofuranosyl oxonium ions of D-glucose or D-fructose, respectively, followed by nucleophilic attack of these ions by D-glucose or D-fructose at either the alpha- or beta-face.  相似文献   

18.
At present, little is known about the mechanisms responsible for intestinal absorption of anthocyanins (ACNs). For example, it has not yet been established if ACNs are absorbed through an active transport mechanism, such as the sodium-dependent glucose transporter (SGLT1), or by passive diffusion. Previously, we found that the absorption of ACNs differs between regions of the digestive tract and is maximal in the jejunum, suggesting that an active transport mechanism is involved. In the present study, we examined the effect of d-glucose (main substrate of SGLT1), phloridzin (inhibitor of SGLT1), and quercetin-3-glucose (Q3G, a flavonol) on the absorption of cyanidin-3-glucoside (C3G; approximately 5 micromol/L) by mouse jejunum mounted in Ussing chambers. We found that the presence of either D-glucose (10, 20, and 40 mmol/L) or phloridzin (50, 100, and 200 micromol/L) resulted in a small but insignificant inhibition of C3G disappearance from the mucosal solution (decrease of disappearance with glucose, 33%; with phloridzin, 18%; NS). However, when the flavonol Q3G (50 micromol/L) was added to the mucosal solution together with the C3G, the disappearance of C3G was significantly decreased (74%; p < 0.001), and Q3G disappeared instead. In addition, we found phloretin and quercetin, the aglycones of phloridzin and Q3G, respectively, present in the mucosal solution and tissue extracts, indicating hydrolysis of these compounds by the enterocytes of the jejunum. In contrast, the aglycone cyanidin was not detected at all. Our results show that in the mouse small intestine, ACN absorption is not solely dependent on the activity of the SGLT1 transporter, as d-glucose and phloridzin had only a slight effect on uptake. Q3G, however, clearly inhibited C3G disappearance. These results suggest that there might be a competitive inhibition between C3G and Q3G absorption. It is possible that an absorption mechanism other than the SGLT1 is involved, which has a structural preference toward flavonols.  相似文献   

19.
Consumption of polyphenols is associated with health promotion through diet, although many are poorly absorbed in animals and humans alike. Lipid peroxides may reach the intestine and initiate deleterious oxidation. Here we measured inhibition of the oxidation of linoleic acid (LA) in authentic fluid from rat small intestine (RIF) by two dietary polyphenols, a flavonoid, epicatechin (EC), and a stilbene, resveratrol (RV), and by gallic (GA) and caffeic (CA) acids, and their partition coefficients. Both polyphenols inhibited 80%, and CA inhibited 65%, of the production of hexanal. GA was the weakest antioxidant in this assay. Interestingly, measuring peroxides production in RIF showed that only epicatechin inhibited the first stage of oxidation. The oxidizing agent, the antioxidant comound, the solution pH and lipophilicity are known to affect the total antioxidative activity. We suggest that the mechanism of this activity changes in accord with the environment: i.e., RV may act as a free radial scavenger, but here, in protecting lipids in intestinal fluid from oxidation, it acts as a hydrogen atom donor. Since the concentration of phenolics is much higher in the intestinal fluid than is ever achieved in plasma or other body tissues, it is suggested that their antioxidant activity could be exerted in the gastrointestinal tract (GIT), breaking the propagation of lipid peroxides oxidation and production of toxic compounds.  相似文献   

20.
Previous studies have shown that deliquescent organic compounds frequently exhibit chemical instability when stored in environmental conditions above their deliquescence relative humidity (RH). The goal of the current study was to investigate the effect of atmospheric moisture on the long-term chemical stability of crystalline sucrose-citric acid mixtures following storage at RHs at and below the mutual deliquescence relative humidity (MDRH). Interestingly, it was found that sucrose hydrolysis can occur below the MDRH of 64% and was observed for samples stored at 54% RH. However, hydrolysis was not seen for samples stored at 33 or 43% RH. The rate of sucrose hydrolysis could be modeled by taking into account the rate and extent of moisture uptake, which in turn was dependent on the composition of the powder and the storage RH. A reaction mechanism initiated by capillary condensation and involving additional deliquescence lowering by the degradation products formed as a result of sucrose hydrolysis (glucose and fructose) was proposed.  相似文献   

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