Influence of Dietary Inulin on Fecal Microbiota, Cardiometabolic Risk Factors, Eicosanoids, and Oxidative Stress in Rats Fed a High-Fat Diet.

The present study examined the influence of inulin on fecal microbiota, cardiometabolic risk factors, eicosanoids, and oxidative stress in rats on a high-fat (HF) diet. Thirty-six male Wistar-Kyoto rats were divided into three dietary groups: standard diet, HF diet, and HF diet + Inulin diet. After 10 weeks, the HF + Inulin diet promoted high dominance of a few bacterial genera including Blautia and Olsenella in feces while reducing richness, diversity, and rarity compared to the HF diet. These changes in fecal microbiota were accompanied by an increased amount of propionic acid in feces. The HF + Inulin diet decreased cardiometabolic risk factors, decreased the amount of the eicosanoids 11(12)-EET and 15-HETrE in the liver, and decreased oxidative stress in blood compared to the HF diet. In conclusion, increasing consumption of inulin may be a useful nutritional strategy to protect against the onset of obesity and its associated metabolic abnormalities by means of modulation of gut microbiota.

Fiber-like Action of d-Fagomine on the Gut Microbiota and Body Weight of Healthy Rats.

The goal of this work is to explore if the changes induced by d-fagomine in the gut microbiota are compatible with its effect on body weight and inflammation markers in rats. Methods: Sprague Dawley rats were fed a standard diet supplemented with d-fagomine (or not, for comparison) for 6 months. The variables measured were body weight, plasma mediators of inflammation (hydroxyeicosatetraenoic acids, leukotriene B4, and IL-6), and the concentration of acetic acid in feces and plasma. The composition and diversities of microbiota in cecal content and feces were estimated using 16S rRNA metabarcoding and high-throughput sequencing. We found that after just 6 weeks of intake d-fagomine significantly reduced body weight gain, increased the plasma acetate concentration, and reduced the plasma concentration of the pro-inflammatory biomarkers' leukotriene B4, interleukin 6 and 12 hydroxyeicosatetraenoic acids. These changes were associated with a significantly increased prevalence of Bacteroides and Prevotella feces and increased Bacteroides, Prevotella, Clostridium, and Dysgonomonas while reducing Anaerofilum, Blautia, and Oribacterium in cecal content. In conclusion, d-fagomine induced changes in the composition and diversity of gut microbiota similar to those elicited by dietary fiber and compatible with its anti-inflammatory and body-weight-reducing effects.

Insights into the Responding Modes of Highly Potent Gadolinium-Based Magnetic Resonance Imaging Probes Sensitive to Zinc Ions.

Zn ions (Zn2+) play an important biological role in many diseases; hence, an imaging method for monitoring the Zn2+ distribution in tissues could provide important clinical insights. Recently, we reported a potent Zn-sensitive probe based on the Gd-DO3A (DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-tricarboxylic acid), modified tyrosine. and di(2-picolyl)amine chelator for this metal cation, which generates an outstanding magnetic resonance imaging (MRI) response. Here we further explored the origin of this unprecedented response and expanded the choice of potential MRI probes by preparing the free acid version of the initial MRI sensor. We report a detailed investigation of the 1H NMR dispersion, 17O NMR, and isothermal titration calorimetry properties of these two MRI probes upon interaction with Zn2+. The performed experiments confirm selective interaction of the MRI probes and target metal cation, which causes substantial changes in the coordination sphere of the paramagnetic center. It also evidenced some aggregation, which enhances the relaxivity response. Interestingly, conversion of the methyl ester to the free carboxylic acid of the tyrosine moiety changes the nature of the aggregates and leads to a smaller relaxivity response. The probes interact with human serum albumin (HSA) in the absence of Zn2+, which leads to a possible modification of the coordination sphere of Gd3+ or a substantial change in the exchange rate of second-sphere water molecules. In the presence of Zn2+, the interaction with HSA is very weak, demonstrating the importance of the Zn2+ coordination sphere in the behavior of these systems.

Evaluation of the Interactions between Human Serum Albumin (HSA) and Non-Steroidal Anti-Inflammatory (NSAIDs) Drugs by Multiwavelength Molecular Fluorescence, Structural and Computational Analysis.

The interaction between drugs and transport proteins, such as albumins, is a key factor in drug bioavailability. One of the techniques commonly used for the evaluation of the drug-protein complex formation is fluorescence. This work studies the interaction of human serum albumin (HSA) with four non-steroidal anti-inflammatory drugs (NSAIDs)-ibuprofen, flurbiprofen, naproxen, and diflunisal-by monitoring the fluorescence quenching when the drug-albumin complex is formed. Two approaches-the double logarithm Stern-Volmer equation and the STAR program-are used to evaluate the binding parameters. The results are analyzed considering the binding properties, determined by using other complementary techniques and the available structural information of albumin complexes with NSAID-related compounds. Finally, this combined analysis has been synergistically used to interpret the binding of flurbiprofen to HSA.

Inter-Individual Variability in Insulin Response after Grape Pomace Supplementation in Subjects at High Cardiometabolic Risk: Role of Microbiota and miRNA.

SCOPE: Dietary polyphenols have shown promising effects in mechanistic and preclinical studies on the regulation of cardiometabolic alterations. Nevertheless, clinical trials have provided contradictory results, with high inter-individual variability. This study explores the role of gut microbiota and microRNAs (miRNAs) as factors contributing to the inter-individual variability in polyphenol response. METHODS AND RESULTS: 49 subjects with at least two factors of metabolic syndrome are divided between responders (n = 23) or non-responders (n = 26), depending on the variation rate in fasting insulin after grape pomace supplementation (6 weeks). The populations of selected fecal bacteria are estimated from fecal deoxyribonucleic acid (DNA) by quantitative real-time polymerase chain reaction (qPCR), while the microbial-derived short-chain fatty acids (SCFAs) are measured in fecal samples by gas chromatography. MicroRNAs are analyzed on a representative sample, followed by targeted miRNA analysis. Responder subjects show significantly lower (p < 0.05) Prevotella and Firmicutes levels, and increased (p < 0.05) miR-222 levels. CONCLUSION: After evaluating the selected substrates for Prevotella and target genes of miR-222, these variations suggest that responders are those subjects exhibiting impaired glycaemic control. This study shows that fecal microbiota and miRNA expression may be related to inter-individual variability in clinical trials with polyphenols.

Implication of gut microbiota in the physiology of rats intermittently exposed to cold and hypobaric hypoxia.

This study examines the influence of intermittent exposure to cold, hypobaric hypoxia, and their combination, in gut microbiota and their metabolites in vivo, and explores their effects on the physiology of the host. Sprague-Dawley rats were exposed to cold (4°C), hypobaric hypoxia (462 torr), or both simultaneously, 4 h/day for 21 days. Biometrical and hematological parameters were monitored. Gut bacterial subgroups were evaluated by qPCR and short-chain fatty acids were determined by gas chromatography in caecum and feces. Cold increased brown adipose tissue, Clostridiales subpopulation and the concentration of butyric and isovaleric acids in caecum. Hypobaric hypoxia increased hemoglobin, red and white cell counts and Enterobacteriales, and reduced body and adipose tissues weights and Lactobacilliales. Cold plus hypobaric hypoxia counteracted the hypoxia-induced weight loss as well as the increase in white blood cells, while reducing the Bacteroidetes:Firmicutes ratio and normalizing the populations of Enterobacteriales and Lactobacilliales. In conclusion, intermittent cold and hypobaric hypoxia exposures by themselves modified some of the main physiological variables in vivo, while their combination kept the rats nearer to their basal status. The reduction of the Bacteroidetes:Firmicutes ratio and balanced populations of Enterobacteriales and Lactobacilliales in the gut may contribute to this effect.

Modifications of Gut Microbiota after Grape Pomace Supplementation in Subjects at Cardiometabolic Risk: A Randomized Cross-Over Controlled Clinical Trial.

Polyphenols are dietary bioactive compounds able to induce modifications in the gut microbiota profile, although more clinical studies are needed. With this aim, a randomized cross-over clinical trial was conducted, where 49 subjects at cardiometabolic risk (exhibiting at least two metabolic syndrome factors) were supplemented with a daily dose of 8 g of grape pomace (GP) for 6 weeks, with an equivalent control (CTL) period. The levels of total bacteria and Bacteroidetes, Firmicutes, Lactobacilliales, Bacteroides and Prevotella were estimated in fecal DNA by quantitative real-time PCR (qPCR), while fecal short-chain fatty acids (SCFAs) were assessed by gas chromatography. Several cardiometabolic markers were evaluated in blood samples. GP reduced insulin levels only in half of the participants (responders). GP supplementation did not cause significant modifications in the microbiota profile of the whole group, except for a tendency (p = 0.059) towards a decrease in the proportion of Lactobacilliales, while it increased the proportion of Bacteroides in non-responder subjects. The reduction of insulin levels in subjects at cardiometabolic risk upon GP supplementation appears not to be induced by changes in the major subgroups of gut microbiota. Further studies at the species level may help to elucidate the possible role of microbiota in GP-induced insulinemic status.

Estimation of the octanol-water distribution coefficient of basic compounds by a cationic microemulsion electrokinetic chromatography system.

The octanol-water partition coefficient (Po/w), or the octanol-water distribution coefficient (Do/w) for ionized compounds, is a key parameter in the drug development process. In a previous work, this parameter was estimated through the retention factor measurements in a sodium dodecyl sulfate (SDS) - microemulsion electrokinetic chromatography (MEEKC) system for acidic compounds. Nonetheless, when ionized basic compounds were analyzed, undesirable ion pairs were formed with the anionic surfactant and avoided a good estimation of log Do/w. For this reason, an alternative MEEKC system based on a cationic surfactant has been evaluated to estimate Po/w or Do/w of neutral compounds and ionized bases. To this end, it has been characterized through the solvation parameter model (SPM) and compared to the octanol-water partition system. Results pointed out that both systems show a similar partition behavior. Hence, the log Po/w of a set of neutral compounds has been successfully correlated against the logarithm of the retention factor (log k) determined in this MEEKC system. Then, the log Do/w of 6 model bases have been estimated at different pH values and they have been compared to data from the literature, determined by the reference shake-flask and potentiometric methods. Good agreement has been observed between the literature and the estimated values when the base is neutral or partially ionized (up to 99% of ionization).

Estimation of the octanol-water distribution coefficient of acidic compounds by microemulsion electrokinetic chromatography.

The feasibility of extending the determination of the lipophilicity of partially ionized acids (log Do/w) by microemulsion electrokinetic chromatography (MEEKC) is tested. Theoretical considerations predict that a linear log Do/w vs. log k correlation can be obtained only when the neutral and ionic forms of an acid follow the same correlation equation and the slope of the correlation is unity. In practice, since the lipophilicity of the neutral acid is much higher than that of the ionic form and the correlation slope is not very different from 1, the general linear correlation for neutral compounds can be applied across most of the ionization range of the acid. The linear correlation between log Po/w and log k of 20 neutral solutes (calibration curve) has been established and extended to 6 acids used as models, tested across their full ionization range. log Do/w-pH, and log k-pH profiles have been obtained for these 6 acids, and plotted log Do/w against log k for any acid at any degree of ionization. Furthermore, the log Do/w of the acids has been estimated from the calibration curve and log k-pH profile, and compared to values in the literature determined using reference methods such as the shake-flask one. Accurate values have been obtained using the MEEKC method when the acids are in their neutral form or partially ionized (ionization degree, α < 0.995). However, this parameter is overestimated when the acids are highly or fully ionized (α ≈ 1). Finally, in order to test the applicability of this method, we have applied the same procedure to estimate log Do/w at pH = 7.4 (blood physiological pH) of a set of 30 additional compounds (including partially and fully ionized acids). The results at this pH follow the same trend observed in the 6 model acids, and validate the application of the method for Do/w determination, except when α is very close to 1.

Lecithin liposomes and microemulsions as new chromatographic phases.

Lecithins are phospholipidic mixtures that can be part of microemulsions and liposomes. In this work, ready-to-use preparations of lecithin have been tested as pseudostationary and mobile phases in EKC and LC, respectively. The selectivity of two EKC systems, one based on lecithin microemulsions (LMEEKC) and another on liposomes (LLEKC), and of a LC system based on lecithin microemulsions (MELC) has been evaluated through the solvation parameter model. In all cases, solute volume and hydrogen-bond basicity are the main descriptors that drive the partition process. While solute volume favors the retention of solutes, hydrogen-bond basicity has the contrary effect. In lecithin-based EKC systems the hydrogen-bond acidity of the solute leads to a higher retention while in the lecithin-based LC system a minor retention is produced. The three lecithin systems have been compared through the solvation parameter model to other chromatographic systems, most of them containing phospholipids. Principal component analysis reveals that lecithin systems cluster together with the other EKC systems based on phospholipids, with an immobilized artificial membrane (IAM) LC system, with the octanol/water reference partition system, and with a SDS-based microemulsion. Thus, they all show similar selectivity. However, the great advantage of using the ready-to use lecithin systems is that the laborious liposome preparation is avoided, and that their commercial availability makes them more affordable than IAM LC columns. Finally, taking into account that lecithin has a high semblance to the mammalian cell membranes composition, the ability of the three lecithin systems to mimic the pass of the solutes through the membranes has been evaluated. Experimental determinations have demonstrated that the skin partition of neutral solutes can be easily emulated, especially using the lecithin-microemulsion EKC method. The model is robust and shows good prediction ability.

The Buckwheat Iminosugar d-Fagomine Attenuates Sucrose-Induced Steatosis and Hypertension in Rats.

SCOPE: This study examines the long-term functional effects of d-fagomine on sucrose-induced factors of metabolic dysfunctions and explores possible molecular mechanisms behind its action. METHODS AND RESULTS: Wistar Kyoto rats are fed a 35% sucrose solution with d-fagomine (or not, for comparison) or mineral water (controls) for 24 weeks. The following are recorded: body weight; energy intake; glucose tolerance; plasma leptin concentration and lipid profile; populations of Bacteroidetes, Firmicutes, bacteroidales, clostridiales, enterobacteriales, and Escherichia coli in feces; blood pressure; urine uric acid and F2t isoprostanes (F2 -IsoPs); perigonadal fat deposition; and hepatic histology and diacylglycerols (DAGs) in liver and adipose tissue. d-Fagomine reduces sucrose-induced hypertension, urine uric acid and F2 -IsoPs (markers of oxidative stress), steatosis, and liver DAGs, without significantly affecting perigonadal fat deposition, and impaired glucose tolerance. It also promotes excretion of enterobacteriales generated by the dietary intervention. CONCLUSION: d-fagomine counteracts sucrose-induced steatosis and hypertension, presumably by reducing the postprandial levels of fructose in the liver.

Effects of combined D-fagomine and omega-3 PUFAs on gut microbiota subpopulations and diabetes risk factors in rats fed a high-fat diet.

Food contains bioactive compounds that may prevent changes in gut microbiota associated with Westernized diets. The aim of this study is to explore the possible additive effects of D-fagomine and ω-3 PUFAs (EPA/DHA 1:1) on gut microbiota and related risk factors during early stages in the development of fat-induced pre-diabetes. Male Sprague Dawley (SD) rats were fed a standard diet, or a high-fat (HF) diet supplemented with D-fagomine, EPA/DHA 1:1, a combination of both, or neither, for 24 weeks. The variables measured were fasting glucose and glucose tolerance, plasma insulin, liver inflammation, fecal/cecal gut bacterial subgroups and short-chain fatty acids (SCFAs). The animals supplemented with D-fagomine alone and in combination with ω-3 PUFAs accumulated less fat than those in the non-supplemented HF group and those given only ω-3 PUFAs. The combined supplements attenuated the high-fat-induced incipient insulin resistance (IR), and liver inflammation, while increasing the cecal content, the Bacteroidetes:Firmicutes ratio and the populations of Bifidobacteriales. The functional effects of the combination of D-fagomine and EPA/DHA 1:1 against gut dysbiosis and the very early metabolic alterations induced by a high-fat diet are mainly those of D-fagomine complemented by the anti-inflammatory action of ω-3 PUFAs.

Combined Buckwheat d-Fagomine and Fish Omega-3 PUFAs Stabilize the Populations of Gut Prevotella and Bacteroides While Reducing Weight Gain in Rats.

Some functional food components may help maintain homeostasis by promoting balanced gut microbiota. Here, we explore the possible complementary effects of d-fagomine and ω-3 polyunsaturated fatty acids (ω-3 PUFAs) eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA 1:1) on putatively beneficial gut bacterial strains. Male Sprague-Dawley rats were supplemented with d-fagomine, ω-3 PUFAs, or both, for 23 weeks. Bacterial subgroups were evaluated in fecal DNA by quantitative real-time polymerase chain reaction (qRT-PCR) and short-chain fatty acids were determined by gas chromatography. We found that the populations of the genus Prevotella remained stable over time in animals supplemented with d-fagomine, independently of ω-3 PUFA supplementation. Animals in these groups gained less weight than controls and rats given only ω-3 PUFAs. d-Fagomine supplementation together with ω-3 PUFAs maintained the relative populations of Bacteroides. ω-3 PUFAs alone or combined with d-fagomine reduced the amount of acetic acid and total short-chain fatty acids in feces. The plasma levels of pro-inflammatory arachidonic acid derived metabolites, triglycerides and cholesterol were lower in both groups supplemented with ω-3 PUFAs. The d-fagomine and ω-3 PUFAs combination provided the functional benefits of each supplement. Notably, it helped stabilize populations of Prevotella in the rat intestinal tract while reducing weight gain and providing the anti-inflammatory and cardiovascular benefits of ω-3 PUFAs.

Determination of the retention factor of ionizable compounds in microemulsion electrokinetic chromatography.

Determination of the retention factor of ionized compounds in microemulsion electrokinetic chromatography requires two mobility measurements at the same pH: one in the presence of the microemulsion and another in plain buffer. However, it has been observed that in some cases subtracting one mobility from another determined in a different medium leads to negative retention factors, which makes no sense from a chemical point of view. This indicates that there is some error in the process which has a direct impact when retention factors are used for further applications. Here, we evaluate how the components of the microemulsion confer different properties to the buffer medium, particularly varying the viscosity parameter (which is inversely related to mobility). Whereas sodium dodecyl sulfate, the surfactant used in the microemulsion, has little effect on the medium viscosity (only an increase of 5%-6%), the presence of 1-butanol, used as a stabilizer, increases it by around 30%. Meanwhile, heptane, which is used as an oil, provokes a slight decrease. Consequently, the mobilities obtained in the microemulsion system are shifted to higher values (less negative mobilities) compared to mobilities obtained in the aqueous buffer, and so one cannot be directly subtracted from the other. Since the microemulsion-buffer medium cannot be directly reproduced, we propose a correction that takes into account the variation of viscosities. This is determined from the electrophoretic mobility of the benzoate ion. As this ion does not interact with the microemulsion, the ratio of its mobilities (measured in plain buffer and microemulsion) is equivalent to the ratio of viscosities, and can be used as the correction factor for other measurements. Thus, mobilities in buffer and microemulsion media are placed on the same scale, overcoming the errors in retention factor determination.

Functional Effects of the Buckwheat Iminosugar d-Fagomine on Rats with Diet-Induced Prediabetes.

SCOPE: The goals of this work are to test if d-fagomine, an iminosugar that reduces body weight gain, can delay the appearance of a fat-induced prediabetic state in a rat model and to explore possible mechanisms behind its functional action. METHODS AND RESULTS: Wistar Kyoto rats were fed a high-fat diet supplemented with d-fagomine (or not, for comparison) or a standard diet (controls) for 24 weeks. The variables measured were fasting blood glucose and insulin levels; glucose tolerance; diacylglycerols as intracellular mediators of insulin resistance in adipose tissue (AT), liver, and muscle; inflammation markers (plasma IL-6 and leptin, and liver and AT histology markers); eicosanoids from arachidonic acid as lipid mediators of inflammation; and the populations of Bacteroidetes, Firmicutes, Enterobacteriales, and Bifidobacteriales in feces. It was found that d-fagomine reduces fat-induced impaired glucose tolerance, inflammation markers, and mediators (hepatic microgranulomas and lobular inflammation, plasma IL-6, prostaglandin E2 , and leukotriene B4 ) while attenuating the changes in the populations of Enterobacteriales and Bifidobacteriales. CONCLUSION: d-Fagomine delays the development of a fat-induced prediabetic state in rats by reducing low-grade inflammation. We suggest that the anti-inflammatory effect of d-fagomine may be linked to a reduction in fat-induced overpopulation of minor gut bacteria.

Mechanistically different effects of fat and sugar on insulin resistance, hypertension, and gut microbiota in rats.

Insulin resistance (IR) and impaired glucose tolerance (IGT) are the first manifestations of diet-induced metabolic alterations leading to Type 2 diabetes, while hypertension is the deadliest risk factor of cardiovascular disease. The roles of dietary fat and fructose in the development of IR, IGT, and hypertension are controversial. We tested the long-term effects of an excess of fat or sucrose (fructose/glucose) on healthy male Wistar-Kyoto (WKY) rats. Fat affects IR and IGT earlier than fructose through low-grade systemic inflammation evidenced by liver inflammatory infiltration, increased levels of plasma IL-6, PGE2, and reduced levels of protective short-chain fatty acids without triggering hypertension. Increased populations of gut Enterobacteriales and Escherichia coli may contribute to systemic inflammation through the generation of lipopolysaccharides. Unlike fat, fructose induces increased levels of diacylglycerols (lipid mediators of IR) in the liver, urine F2-isoprostanes (markers of systemic oxidative stress), and uric acid, and triggers hypertension. Elevated populations of Enterobacteriales and E. coli were only detected in rats given an excess of fructose at the end of the study. Dietary fat and fructose trigger IR and IGT in clearly differentiated ways in WKY rats: early low-grade inflammation and late direct lipid toxicity, respectively; gut microbiota plays a role mainly in fat-induced IR, and hypertension is independent of inflammation-mediated IR. The results provide evidence that suggests that the combination of fat and sugar is potentially more harmful than fat or sugar alone when taken in excess.

Molecular interactions between warfarin and human (HSA) or bovine (BSA) serum albumin evaluated by isothermal titration calorimetry (ITC), fluorescence spectrometry (FS) and frontal analysis capillary electrophoresis (FA/CE).

Interaction thermodynamics between warfarin, a very popular anticoagulant, and Sudlow I binding site of human (HSA) or bovine (BSA) serum albumin have been examined in strictly controlled experimental conditions (HEPES buffer 50 mM, pH 7.4 and 25 °C) by means of isothermal titration calorimetry (ITC), fluorescence spectrometry (FS) and frontal analysis capillary electrophoresis (FA/CE). Each technique is based on measurements of a different property of the biochemical system, and then the results allow a critical discussion about the suitability of each approach to estimate the drug-protein binding parameters. The strongest interaction step is properly evaluated by the three assayed approaches being the derived binding constants strongly consistent: from 4 × 104 to 7 × 104 for HSA and from 0.8 × 105 to 1.2 × 105 for BSA. Binding enthalpy variations also show consistent results: -5.4 and -5.6 Kcal/mol for HSA and -4.3 and -3.7 Kcal/mol for BSA, as measured by ITC and FS, respectively. Further high order interaction events for both albumins are detected only by FA/CE.

Modeling Aquatic Toxicity through Chromatographic Systems.

Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information. In this work, we have studied the similarity in the response of the toxicity to different species and we have selected eight representative aquatic species (including tadpoles, fish, water fleas, protozoan, and bacteria) with known nonspecific toxicity to chemical substances. Next, we have selected four chromatographic systems offering good perspectives for surrogation of the eight selected aquatic systems, and thus prediction of toxicity from the chromatographic measurement. Then toxicity has been correlated to the chromatographic retention factor. Satisfactory correlation results have been obtained to emulate toxicity in five of the selected aquatic species through some of the chromatographic systems. Other aquatic species with similar characteristics to these five representative ones could also be emulated by using the same chromatographic systems. The final aim of this study is to model chemical products toxicity to aquatic species by means of chromatographic systems to reduce in vivo testing.

Fate of d-Fagomine after Oral Administration to Rats.

d-Fagomine is an iminosugar found in buckwheat that is capable of inhibiting the adhesion of potentially pathogenic bacteria to epithelial mucosa and reducing the postprandial blood glucose concentration. This paper evaluates the excretion and metabolism of orally administered d-fagomine in rats and compares outcomes with the fate of 1-deoxynojirimycin. d-Fagomine and 1-deoxynojirimycin show similar absorption and excretion kinetics. d-Fagomine is partly absorbed (41-84%, dose of 2 mg/kg of body weight) and excreted in urine within 8 h, while the non-absorbed fraction is cleared in feces within 24 h. d-Fagomine is partially methylated (about 10% in urine and 3% in feces). The concentration of d-fagomine in urine from 1 to 6 h after administration is higher than 10 mg/L, the concentration that inhibits adhesion of Escherichia coli. Orally administered d-fagomine is partially absorbed and then rapidly excreted in urine, where it reaches a concentration that may be protective against urinary tract infections.

Advances in the analysis of iminocyclitols: Methods, sources and bioavailability.

Iminocyclitols are chemically and metabolically stable, naturally occurring sugar mimetics. Their biological activities make them interesting and extremely promising as both drug leads and functional food ingredients. The first iminocyclitols were discovered using preparative isolation and purification methods followed by chemical characterization using nuclear magnetic resonance spectroscopy. In addition to this classical approach, gas and liquid chromatography coupled to mass spectrometry are increasingly used; they are highly sensitive techniques capable of detecting minute amounts of analytes in a broad spectrum of sources after only minimal sample preparation. These techniques have been applied to identify new iminocyclitols in plants, microorganisms and synthetic mixtures. The separation of iminocyclitol mixtures by chromatography is particularly difficult however, as the most commonly used matrices have very low selectivity for these highly hydrophilic structurally similar molecules. This review critically summarizes recent advances in the analysis of iminocyclitols from plant sources and findings regarding their quantification in dietary supplements and foodstuffs, as well as in biological fluids and organs, from bioavailability studies.