pyrimidinones and vicine

Topics: Erythrocytes; Favism; Free Radicals; Glucosephosphate Dehydrogenase Deficiency; Glucosides; Humans; Pyrimidinones; Vicia faba

The faba bean is one of the earliest domesticated crops, with both economic and environmental benefits. Like most legumes, faba beans are high in protein, and can be used to contribute to a balanced diet, or as a meat substitute. However, they also produce the anti-nutritional compounds, vicine and convicine (v-c), that when enzymatically degraded into reactive aglycones can potentially lead to hemolytic anemia or favism. Current methods of analysis use LC-UV, but are only suitable at high concentrations, and thus lack the selectivity and sensitivity to accurately quantitate the low-v-c genotypes currently being developed. We have developed and fully validated a rapid high-throughput LC-MS method for the analysis of v-c in faba beans by optimizing the extraction protocol and assessing the method of linearity, limit of detection, limit of quantitation, accuracy, precision and matrix effects. This method uses 10-times less starting material; removes the use of buffers, acids and organic chemicals; and improves precision and accuracy when compared to current methods.

Topics: Favism; Glucosides; Pyrimidinones; Uridine; Vicia faba

Epilepsy disease is characterized by the neuronal dysfunction or abnormal neuronal activity of the brain which is regulated by astrocytes. These are glial cells and found to be the major regulators of the brain which are guided by the occurrence of adenosine kinase (ADK) enzyme in the central nervous system (CNS). During the normal physiological environment, ADK maintains the level of adenosine in the CNS. Dysfunction of ADK levels results in accumulation of adenosine levels in the CNS that leads to the pathophysiology of the brain such as astrogliosis which is a pathological hallmark of epileptic seizures. Vicine, an alkaloid glycoside in bitter gourd juice (Momordica charantia) is found to be toxic to the human system if the bitter gourd juice is consumed more. This compound inhibits ADK enzyme activity to lead epilepsy and seizure. Here, the toxic effect of vicine targeting ADK using computational predictions was investigated. The 3-dimensional structure of ADK has been constructed using I-Tasser, which has been refined by ModRefiner, GalaxyRefine, and 3D refine and it was endorsed using PROCHECK, ERRAT, and VADAR. 3D structure of the ligand molecule has been obtained from PubChem. Molecular docking has been achieved using AutoDock 4.2 software, from which the outcome showed the effective interaction between vicine and ADK, which attains binding free energy (∆G) of - 4.13 kcal/mol. Vicine molecule interacts with the active region ARG 149 of ADK and inhibits the functions of ADK that may cause imbalance in energy homeostasis. Also, pre-ADMET results robustly propose in which vicine possesses toxicity, and meanwhile, from the Ames test, it was shown as mutagenic. Hence, the results from our study suggest that vicine was shown to be toxic that suppresses the ADK activity to undergo pathological conditions in the neuronal junctions to lead epilepsy.

Topics: Adenosine Kinase; Alkaloids; Animals; Drug Development; Glucosides; Glycosides; Humans; Mice; Molecular Docking Simulation; Momordica charantia; Nervous System Diseases; Protein Structure, Secondary; Pyrimidinones; Rats; Toxins, Biological

Faba bean (

Topics: Deep Learning; Genotype; Glucosides; Polymorphism, Single Nucleotide; Pyrimidinones; Regulatory Sequences, Nucleic Acid; Seeds; Synteny; Transcription Factors; Uridine; Vicia faba

Faba bean (Vicia faba L.) provides environmental and health benefits; however, the presence of the pyrimidine glycosides vicine and convicine (v-c) in its seeds limits consumption. Low v-c genotypes have been introduced, but the convicine levels in these genotypes have not been quantified. To improve detection, the polar nature of v-c was exploited by implementing hydrophilic interaction liquid chromatography (HILIC). A sample preparation method using a two-step extraction was developed for use with UV and/or tandem mass spectrometry (SRM) detection. The HILIC-UV method was suitable for over three orders of magnitude, covering the range of v-c concentrations in faba bean seeds across all genotypes tested. The linear range of HILIC-SRM was slightly less (∼3 orders of magnitude), but improved sensitivity and selectivity make it more suitable for quantifying low v-c samples. The analysis of 13 genotypes suggests that v-c concentrations in faba bean seeds may be independent quantitative traits.

Topics: Chromatography, Liquid; Glucosides; Hydrophobic and Hydrophilic Interactions; Pyrimidinones; Seeds; Uridine; Vicia faba

Topics: Adult; Child; Child, Preschool; Erythrocytes; Female; Glucosephosphate Dehydrogenase Deficiency; Glucosides; Hemolysis; Humans; Male; Pyrimidinones; Seeds; Vicia faba

Although faba bean provides environmental and health benefits, vicine and convicine (v-c) limit its use as a source of vegetable protein. Crop improvement efforts to minimize v-c concentration require low-cost, rapid screening methods to distinguish between high and low v-c genotypes to accelerate development of new cultivars and to detect out-crossing events. To assist crop breeders, we developed a unique and rapid screening method that uses a 60 s instrumental analysis step to accurately distinguish between high and low v-c genotypes. The method involves flow injection analysis (FIA) coupled with tandem mass spectrometry (i.e., selective reaction monitoring, SRM). Using seeds with known v-c levels as calibrants, measured v-c levels were comparable with liquid chromatography (LC)-SRM results and the method was used to screen 370 faba bean genotypes. Widespread use of FIA-SRM will accelerate breeding of low v-c faba bean, thereby alleviating concerns about anti-nutritional effects of v-c in this crop.

Topics: Chromatography, Liquid; Flow Injection Analysis; Glucosides; High-Throughput Screening Assays; Pyrimidinones; Seeds; Tandem Mass Spectrometry; Uridine; Vicia faba

Faba bean (Vicia faba) vicine and convicine (V-C) aglycones (divicine and isouramil respectively) provoke an acute hemolytic anemia called favism in individuals with a glucose-6-phosphate dehydrogenase (G6PD) enzyme defect in their red blood cells. Geneticists/plant breeders are working with faba bean to decrease V-C levels to improve public acceptance of this high-protein pulse crop. Here, we present a fast and simple ex vivo in vitro bioassay for V-C toxicity testing of faba bean or faba bean food products.. We have shown that 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU)-treated (i.e., sensitized) normal red blood cells, like G6PD-defective blood, displayed (i) continuous glutathione (GSH) depletion with no regeneration as incubation time and the dose of aglycones increased, (ii) progressive accumulation of denatured hemoglobin products into high molecular weight (HMW) proteins with increased aglycone dose, (iii) both band 3 membrane proteins and hemichromes, in HMW protein aggregates. We have also demonstrated that sensitized red blood cells can effectively differentiate various levels of toxicity among faba bean varieties through the two hemolysis biomarkers: GSH depletion and HMW clumping.. BCNU-sensitized red blood cells provide an ideal model for favism blood, to assess and compare the toxicity of faba bean varieties and their food products. © 2018 Society of Chemical Industry.

Topics: Biological Assay; Erythrocytes; Favism; Glucosephosphate Dehydrogenase; Glucosides; Hemolysis; Humans; Pyrimidinones; Uridine; Vicia faba

The faba bean (Vicia faba L.) is a potential source of proteins for poultry, mainly for laying hens whose protein requirements are lower than those of other birds such as growing broilers and turkeys. However, this feedstuff contains anti-nutritional factors, that is, vicine (V) and convicine (C) that are already known to reduce laying hen performance. The aim of the experiment reported here was to evaluate the effects of a wide range of dietary V and C concentrations in laying hens. Two trials were performed with laying hens fed diets including 20% or 25% of faba bean genotypes highly contrasting in V+C content. In Trial 1, faba beans from two tannin-containing cultivars, but with high or low V+C content were dehulled in order to eliminate the tannin effect. In addition to the contrasting levels of V+C in the two cultivars, two intermediate levels of V+C were obtained by mixing the two cultivars (70/30 and 30/70). In Trial 2, two isogenic zero-tannin faba bean genotypes with high or low V+C content were used. In both trials, a classical corn-soybean diet was also offered to control hens. Each experimental diet was given to 48 laying hens for 140 (Trial 1) or 89 (Trial 2) days. Laying performance and egg quality were measured. The redox sensitivity of red blood cells (RBCs) was assessed by measuring hemolysis and reduced glutathione (GSH) concentration in these cells. Egg weight was significantly reduced by the diets containing the highest concentrations of V+C (P<0.0001) in Trial 1 and slightly reduced (P<0.10) in Trial 2, but only weak linear relationships between egg weight and dietary V+C concentration were established. No negative effect of V+C level was observed for egg quality parameters. In contrast, certain parameters (i.e. Haugh units, yolk color) were improved by feeding low V+C diets (P<0.05). Hemolysis of RBCs was higher in hens fed high V+C diets. A decrease in GSH concentration in RBCs of hens fed the highest levels of V+C was observed. Faba bean genotypes with low concentrations of V+C can therefore be used in laying hen diets up to 25% without any detrimental effects on performance levels or egg characteristics, without any risk of hemolysis of RBCs.

Topics: Animal Feed; Animals; Chickens; Diet; Erythrocytes; Female; Genotype; Glucosides; Glycine max; Ovulation; Ovum; Pyrimidinones; Tannins; Uridine; Vicia faba

The aglycones of vicine and convicine, divicine and isouramil, are the causative agents of favism and, therefore, should be analysed along with vicine and convicine in research seeking to eliminate them. This study investigated the stability of the aglycones produced by hydrolysis with β-glucosidase. Reversed-phase, high-performance liquid chromatography (HPLC) with UV detection was shown to be able to observe both aglycone formation and further reactions in isolated fractions and extract made from faba bean and in faba bean suspension. Divicine and isouramil were unstable and degraded almost completely in extract in 60min and completely in fractions in 120min at a pH of 5 at 37°C. Adding sodium ascorbate delayed degradation of divicine. Divicine was more stable at 20°C than at 37°C. Being able to show formation and degradation of the aglycones, the proposed method allows monitoring of the vicine and convicine detoxification process.

Topics: Barbiturates; beta-Glucosidase; Favism; Glucosides; Hydrolysis; Pyrimidinones; Uridine; Vicia faba

In spite of its positive repercussions on nutrition and environment, faba bean still remains an underutilized crop due to the presence of some undesired compounds. The pyrimidine glycosides vicine and convicine are precursors of the aglycones divicine and isouramil, the main factors of favism, a genetic condition which may lead to severe hemolysis after faba bean ingestion. The reduction of vicine and convicine has been targeted in several studies but little is known about their degradation. In this study, the hydrolysis kinetics of vicine and convicine and their derivatives during fermentation with L. plantarum DPPMAB24W was investigated. In particular, a specific HPLC method coupled to ESI-MS and MS/MS analysis, including the evaluation procedure of the results, was set up as the analytical approach to monitor the compounds. The degradation of the pyrimidine glycosides in the fermented flour was complete after 48 h of incubation and the aglycone derivatives could not be detected in any of the samples. The toxicity of the fermented faba bean was established through ex-vivo assays on human blood, confirming the experimental findings. Results indicate that mild and cost effective bioprocessing techniques can be applied to detoxify faba bean also for industrial applications.

Topics: Barbiturates; Biotransformation; Fermentation; Flour; Food Technology; Glucosides; Humans; Hydrogen-Ion Concentration; Hydrolysis; Lactobacillus plantarum; Pyrimidinones; Spectrometry, Mass, Electrospray Ionization; Uridine; Vicia faba

The effects of air classification and lactic acid bacteria fermentation on the reduction of anti-nutritional factors (vicine and convicine, trypsin inhibitor activity, condensed tannins and phytic acid) and in vitro protein and starch digestibility of faba bean flour were studied. Free amino acid (FAA) profile analysis was also carried out. Air classification allowed the separation of the flour into protein and starch rich fractions, showing different chemical compositions and microstructures. Lactobacillus plantarum growth and acidification in faba bean flour and its fractions were assessed. The anti-nutritional compounds were separated mostly to the fine protein-rich fraction. Fermentation caused the decrease of vicine and convicine contents by more than 91% and significantly reduced trypsin inhibitor activity and condensed tannins (by more than 40% in the protein-rich fraction). No significant (P>0.05) variation was observed for total phenols and phytic acid content. Fermentation increased the amount of FAA, especially of the essential amino acids and γ-aminobutyric acid, enhanced the in vitro protein digestibility and significantly lowered the hydrolysis index. This work showed that the combination of air classification and fermentation improved nutritional functionality of faba bean flour which could be utilized in various food applications.

Topics: Air; Amino Acids; Fermentation; Flour; Food Microbiology; gamma-Aminobutyric Acid; Glucosides; Lactobacillaceae; Lactobacillus plantarum; Phytic Acid; Pyrimidinones; Starch; Vicia faba

The study of metabolically labeled or probe-modified proteins is an important area in chemical proteomics. Isolation and purification of the protein targets is a necessary step before MS identification. The biotin-streptavidin system is widely used in this process, but the harsh denaturing conditions also release natively biotinylated proteins and non-selectively bound proteins. A cleavable linker strategy is a promising approach for solving this problem. Though several cleavable linkers have been developed and tested, an efficient, easily synthesized, and inexpensive cleavable linker is a desirable addition to the proteomics toolbox. Here, we describe the chemical proteomics application of a vicinal diol cleavable linker. Through easy-to-handle chemistry we incorporate this linker into an activity-based probe and a biotin alkyne tag amenable for bioorthogonal ligation. With these reagents, background protein identifications are significantly reduced relative to standard on-bead digestion.

Topics: Biotin; Cathepsins; Cross-Linking Reagents; Glucosides; Mass Spectrometry; Proteins; Proteome; Proteomics; Pyrimidinones

The α-hydroxy ketones are used as building blocks for compounds of pharmaceutical interest (such as antidepressants, HIV-protease inhibitors and antitumorals). They can be obtained by the action of enzymes or whole cells on selected substrates, such as diketones. We have studied the enantiospecificities of several fungal (AKR3C1, AKR5F and AKR5G) and human (AKR1B1 and AKR1B10) aldo-keto reductases in the production of α-hydroxy ketones and diols from vicinal diketones. The reactions have been carried out with pure enzymes and with an NADPH-regenerating system consisting of glucose-6-phosphate and glucose-6-phosphate dehydrogenase. To ascertain the regio and stereoselectivity of the reduction reactions catalyzed by the AKRs, we have separated and characterized the reaction products by means of a gas chromatograph equipped with a chiral column and coupled to a mass spectrometer as a detector. According to the regioselectivity and stereoselectivity, the AKRs studied can be divided in two groups: one of them showed preference for the reduction of the proximal keto group, resulting in the S-enantiomer of the corresponding α-hydroxy ketones. The other group favored the reduction of the distal keto group and yielded the corresponding R-enantiomer. Three of the AKRs used (AKR1B1, AKR1B10 and AKR3C1) could produce 2,3-butanediol from acetoin. We have explored the structure/function relationships in the reactivity between several yeast and human AKRs and various diketones and acetoin. In addition, we have demonstrated the utility of these AKRs in the synthesis of selected α-hydroxy ketones and diols.

Topics: Alcohol Oxidoreductases; Aldehyde Reductase; Aldo-Keto Reductases; Butylene Glycols; Catalysis; Fungal Proteins; Glucose-6-Phosphate; Glucosephosphate Dehydrogenase; Glucosides; Humans; Ketones; Kinetics; NADP; Oxidation-Reduction; Pyrimidinones; Stereoisomerism; Structure-Activity Relationship; Yeasts

The vicinal amino alcohol is a common motif in natural products and pharmaceuticals. Amino acids constitute a natural, inexpensive, and enantiopure choice of starting material for the synthesis of such functionalities. However, the matters concerning diastereoselectivity are not obvious. This Perspective takes a look in the field of diastereoselective synthesis of vicinal amino alcohols starting from amino acids using various methods.

Topics: Aldehydes; Amino Alcohols; Glucosides; Molecular Structure; Oxidation-Reduction; Pyrimidinones; Stereoisomerism

N-(4-toluenesulfonyloxy)carbamates based on a range of common amine protecting groups serve as preformed nitrogen sources in the intermolecular osmium-catalyzed oxyamination reaction of a variety of mono-, di-, and trisubstituted alkenes. The reactions occur with low catalyst loadings and good yields and afford high regioselectivity for unsymmetrically substituted alkenes.

Topics: Alkenes; Amination; Carbamates; Catalysis; Glucosides; Molecular Structure; Osmium; Pyrimidinones

A mild and user-friendly one-pot oxidative cleavage of vicinal diols to their corresponding (di)carboxylic acids using AZADOs and PhI(OAc)(2) is described. 1,2-Diols and 2,3-diols as well as 1,2,3-triol gave one- or two-carbon-unit-shorter carboxylic acids. Internal vicinal diols also smoothly underwent one-pot oxidative cleavage to afford the corresponding dicarboxylic acids. Cyclic vicinal diols are converted to their corresponding open-form dicarboxylic acids.

Topics: Carboxylic Acids; Catalysis; Free Radicals; Glucosides; Iodobenzenes; Molecular Structure; Nitrogen Oxides; Oxidation-Reduction; Pyrimidinones

This computational study provoked by the process of peptide bond formation in the ribosome investigates the influence of the vicinal OH group in monoacylated diols on the elementary acts of ester aminolysis. Two alternative approaches for this influence on ester ammonolysis were considered: stabilization of the transition states by hydrogen bonds and participation of the vicinal hydroxyl in proton transfer (proton shuttle). The activation due to hydrogen bonds of the vicinal hydroxyl via tetragonal transition states was rather modest; the free energy of activation was reduced by only 5.2 kcal/mol compared to the noncatalyzed reaction. The catalytic activation via the proton shuttle mechanism with participation of the vicinal OH in the proton transfer via hexagonal transition states resulted in considerable reduction of the free energy of activation to 33.5 kcal/mol, i.e., 16.0 kcal/mol lower than in the referent process. Accounting for the influence of the environment on the reaction center by a continuum model (for ε from 5 to 80) resulted in further stabilization of the rate-determining transition state by 4-5 kcal/mol. The overall reduction of the reaction barrier by about 16 kcal/mol as compared to the noncatalyzed process corresponds to about 10(9)-fold acceleration of the reaction, in agreement with the experimental estimate for acceleration of this process in the ribosome.

Topics: Ammonia; Catalysis; Esters; Glucosides; Hydrogen Bonding; Hydroxides; Molecular Conformation; Molecular Dynamics Simulation; Protons; Pyrimidinones; Thermodynamics; Water

The synthesis of the stereospecifically fluorinated difluoro- and trifluoro- rac-3 and rac-4 is described where the fluorine atoms are positioned adjacent/vicinal to each other and the physical characteristics of these candidate liquid crystals including negative dielectric anisotropy are measured and rationalised.

Topics: Alkylation; Anisotropy; Fluorine; Gases; Glucosides; Liquid Crystals; Models, Molecular; Molecular Structure; Pyrimidinones; Stereoisomerism

The antinutritional factors (ANFs) present in Vicia spp. seeds are a major constraint to the wider utilization of these crops as grain legumes. In the case of faba bean (Vicia faba L.), a breeding priority is the absence vicine and convicine (v-c); responsible for favism in humans and for the reduced animal performance or low egg production in laying hens. The discovery of a spontaneous mutant allele named vc-, which induces a 10-20 fold reduction of v-c contents, may facilitate the process. However, the high cost and difficulty of the chemical detection of v-c seriously restricts the advances in breeding-selection. To identify random amplified polymorphic DNA (RAPD) markers linked to this gene, we have analysed an F(2 )population derived from a cross between a line with high v-c content (Vf6) and the vc- genotype (line 1268). Quantification of v-c was done by spectrophotometry on the parents and the F(2 )population (n = 136). By using bulked segregant analysis (BSA), two RAPD markers linked in coupling and repulsion phase to the allele vc- were identified and further converted into sequence characterized amplified regions (SCARs). Amplification of SCARS was more consistent, although the initial polymorphism between pools was lost. To recover the polymorphisms several approaches were explored. Restriction digestion with HhaI (for SCAR SCH01(620)) and RsaI (for SCAR SCAB12(850)) revealed clear differences between the parental lines. The simultaneous use of the two cleavage amplified polymorphism (CAP) markers will allow the correct fingerprinting of faba bean plants and can be efficiently used in breeding selection to track the introgression of the vc- allele to develop cultivars with low v-c content and improved nutritional value.

Topics: Animals; Crosses, Genetic; Genetic Markers; Glucosides; Humans; Polymorphism, Genetic; Pyrimidinones; Random Amplified Polymorphic DNA Technique; Uridine; Vicia faba

Pinacol coupling of alkyl dinitrones mediated by SmI2 was achieved in the presence of a proton source allowing the synthesis of cyclic vicinal diamines with good cis-selectivity.

Topics: Crystallography, X-Ray; Cyclization; Diamines; Glucosides; Heterocyclic Compounds; Hydrazones; Iodides; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Structure; Nitrogen Oxides; Oximes; Pyrimidinones; Samarium

A kinetic study of the tin(II) chloride catalyzed reaction of diazodiphenylmethane with ethylene glycol in dimethoxyethane is reported. The preparation and characterization of ethylene glycol monodiphenylmethyl ether, the main product from this reaction, is also reported as well as the preparation of the two diphenylmethyl monoethers of methyl 4,6-O-benzylidene-alpha-D-glucopyranoside. An unexpected relationship between the concentration of ethylene glycol and the pseudo first-order rate constant, k', was observed in these reactions. For low concentrations of ethylene glycol (below 0.06 M), k' increases with increasing concentration of the diol. This trend is reversed for high concentrations of ethylene glycol (from about 0.06 to about 0.2 M). The apparent rate constant was also inversely related to the initial concentration of diazodiphenylmethane for the concentrations investigated. These results make the previously proposed involvement of a 1,3,2-dioxastannolane intermediate very unlikely [Petursson, S.; Webber, J.M. Carbohydr. Res. 1982, 103, 41-52]. The results suggest that more likely intermediates for these reactions involve tin(II) chloride complexes in a dynamic equilibrium with the diol.

Topics: Azo Compounds; Catalysis; Dose-Response Relationship, Drug; Ethyl Ethers; Ethylene Glycol; Glucosides; Kinetics; Methods; Pyrimidinones; Tin Compounds

When young rats were fed a diet containing common vetch seed for 1 month, they excreted in the urine approximately 7 times more thiocyanate than they had ingested. Vicianin, prunasin, and beta-cyanoalanine were identified as principal dietary sources of the excreted thiocyanate. Vicianin was isolated by chromatography and crystallization. Its structure was confirmed by mass spectrometry and by identification of its monosaccharides and aglycon. Prunasin was identified chromatographically by HPLC. The combined seed content of vicianin (0.68 micromol/g) and prunasin (0.16 micromol/g) corresponded to the cyanogen content of the seed (0.91 +/- 0.14 micromol/g; n = 7), determined as cyanide after autolysis. When vicianin was fed, the urinary thiocyanate output was 21% of the ingested amount of vicianin, whereas beta-cyanoalanine yielded a urinary thiocyanate output of < 0.2%. Calculations show that 73% of the thiocyanate can be derived from vicianin and prunasin, with 27% derived from beta-cyanoalanine. High urinary output of thiocyanate has been associated with endocrine and neurological disorders.

Topics: Alanine; Animals; Diet; Fabaceae; Glucosides; Male; Nitriles; Pyrimidinones; Rats; Rats, Sprague-Dawley; Seeds; Thiocyanates; Toxins, Biological; Weaning

Studies have demonstrated significant heterogeneity in neutrophil granule morphology and physical density. Using cytochemical methods to localize peroxidase and vicinal glycol containing complex carbohydrates we examined the heterogeneity of neutrophil granules from intact human neutrophil granules in 13 isolated granule density fractions, calcium ionophore A23187 treated neutrophils and neutrophils from patients with Chediak-Higashi Syndrome and Specific Granule Deficiency. At least four distinct populations of peroxidase positive granules (PPG) were identified based on peroxidase staining, vicinal glycol staining, morphology, beta-glucuronidase and defensin content, and physical density characteristics. The smallest (0.15 micron diameter) PPG was the least dense granule, had a unique peroxidase/beta-glucuronidase ratio, reacted intensely for vicinal glycols, resisted ionophore degranulation and was not consumed in giant granule formation in Chediak-Higashi Syndrome. The largest (0.3 micron average diameter) and most physically dense PPG was rich in defensins, stained weakly for vicinal glycols, and was absent in specific granule deficiency. These studies demonstrate and correlate morphologic, biochemical, functional, and pathologic differences in PPG populations.

Topics: Adult; Blood Bactericidal Activity; Blood Proteins; Calcimycin; Chediak-Higashi Syndrome; Child; Coloring Agents; Cytoplasmic Granules; Defensins; Glucosides; Glucuronidase; Glycols; Humans; Ionophores; Microscopy, Electron; Neutrophils; Peroxidase; Peroxidases; Pyrimidinones

The balanced polymorphism of glucose-6-phosphate dehydrogenase deficiency (G6PD-) is believed to have evolved through the selective pressure of malarial combined with consumption of fava beans. The implicated fava bean constituents are the hydroxypyrimidine glucosides vicine and convicine, which upon hydrolysis of their beta-O-glucosidic bond, became protein pro-oxidants. In this work we show that the glucosides inhibit the growth of Plasmodium falciparum, increase the hexose-monophosphate shunt activity and the phagocytosis of malaria-infected erythrocytes. These activities are exacerbated in the presence of beta-glucosidase, implicating their pro-oxidant aglycones in the toxic effect, and are more pronounced in infected G6PD- erythrocytes. These results suggest that G6PD- infected erythrocytes are more susceptible to phagocytic cells, and that fava bean pro-oxidants are more efficiently suppressing parasite propagation in G6PD- erythrocytes, either by directly affecting parasite growth, or by means of enhanced phagocytic elimination of infected cells. The present findings could account for the relative resistance of G6PD- bearers to falciparum malaria, and establish a link between dietary habits and malaria in the selection of the G6PD- genotype.

Topics: Animals; Erythrocytes; Fabaceae; Female; Glucosephosphate Dehydrogenase; Glucosephosphate Dehydrogenase Deficiency; Glucosides; Humans; Hydrogen-Ion Concentration; Hydrolysis; Malaria, Falciparum; Male; Pentose Phosphate Pathway; Phagocytosis; Plants, Medicinal; Plasmodium falciparum; Pyrimidinones; Uridine

Uridine (C9H12N2O6) was applied as an internal standard for the determination of glucopiranosides in faba bean seeds by the HPLC method. The relative UV response factors of vaccine or convicine to uridine were determined (1.12 and 0.79, respectively). The changes in the content of vaccine and convicine during ripening of faba bean seeds were followed. It was observed that with the increase in the seed dry matter content from 0.18 kg/kg to 0.78 kg/kg, the dry matter based content of vaccine decreased from 26.225 g/kg to 0.243 g/kg, and that of convicine from 9.051 g/kg to 0.094 g/kg.

Topics: Chromatography, High Pressure Liquid; Fabaceae; Glucosides; Plants, Medicinal; Pyrimidinones; Seeds; Toxins, Biological; Uridine

Changes in the concentrations of vicine, convicine and L-DOPA in two cultivars of Vicia faba L. seeds in different stages of pod development were determined by high performance liquid chromatography (HPLC). The vicine and convicine content was highest in fresh green cotyledons (moisture content about 80%) and gradually declined until a constant level was reached when seed dry matter percentage was around 40%. A similar pattern of variation in glucoside concentration was observed for the seed coat. The pods contained neither vicine nor convicine but they were particularly rich in L-DOPA. These compounds were not homogeneously distributed in the seeds.

Topics: Chromatography, High Pressure Liquid; Fabaceae; Favism; Glucosides; Levodopa; Plants, Medicinal; Pyrimidinones; Seeds; Toxins, Biological; Uridine

This study in the rat established the effects that a broad-spectrum and poorly absorbed antibiotic, neomycin sulfate, had on the in vitro and in vivo hydrolysis of vicine and convicine by the intestinal microflora, and on vicine- and convicine-induced depletion of blood glutathione and the resulting toxicity. The in vitro studies demonstrated that digesta from the caecum and large intestine were highly effective in hydrolysing vicine and convicine, whereas digesta from the same sections of the gastro-intestinal tract of neomycin-treated rats were much less effective (P < 0.0001). The in vivo studies showed that the total amount of vicine and convicine excreted in the urine and faeces was much greater in neomycin-treated rats compared with controls (P < 0.05), indicating the ability of neomycin to increase the amount of glycosides, particularly that of vicine, excreted in the faeces. The ability of glycosides to decrease the concentration of glutathione in blood (P < 0.05) and to increase rat mortality was greatly reduced in rats that were treated with neomycin, particularly in those treated ip with the toxin. Thus, the results demonstrated that neomycin reduced the rate at which vicine and convicine were hydrolysed in the lower section of the gastro-intestinal tract, and that neomycin treatment was associated with a reduced toxicity of the glycosides.

Topics: Administration, Oral; Analysis of Variance; Animals; Cecum; Chromatography, High Pressure Liquid; Drug Interactions; Feces; Gastrointestinal Contents; Glucosides; Glutathione; Hydrolysis; Injections, Intraperitoneal; Intestine, Large; Male; Neomycin; Pyrimidinones; Rats; Rats, Sprague-Dawley; Toxins, Biological; Uridine

Saccharomyces cerevisiae (ATP) and cytosolic rat liver (GTP) phospho enol pyruvate carboxykinases (EC 4.1.1.49/32) have been labeled with N-(1-pyrenyl)-iodoacetamide. Reagent incorporation was completely prevented by the presence of the respective nucleoside diphosphate plus MnCl2. Under appropriate conditions, 2 mol of reagent per mol of enzyme subunit were incorporated. The fluorescence spectra of the labeled proteins showed the pyrene excimer emission band. The pyrenyl-derivatized enzymes were digested with trypsin after carboxymethylation, and two labeled peptides were isolated for each carboxykinase upon reverse-phase high-performance liquid chromatography. Automated Edman degradation of the labeled peptides indicated that cysteines 364 and 457 (yeast enzyme), and cysteines 288 and 413 (rat enzyme) were labeled with the fluorescence SH-specific reagent. The relative reactivity of these residues was characterized. Labeling experiments utilizing the 5,5'-dithiobis(2-nitrobenzoate)-oxidized enzymes suggested that the reactive SH-groups occupy a vicinal position in the tertiary structure of the proteins, probably in the nucleotide-binding region.

Topics: Adenosine Triphosphate; Amino Acid Sequence; Animals; Cysteine; Cytosol; Dithionitrobenzoic Acid; Fluorescent Dyes; Glucosides; Guanosine Triphosphate; Iodoacetamide; Liver; Phosphoenolpyruvate Carboxykinase (GTP); Pyrimidinones; Rats; Saccharomyces cerevisiae

Topics: Fabaceae; Favism; Glucosides; Humans; Plants, Medicinal; Pyrimidinones; Toxins, Biological

The toxic glycosides vicine and convicine which are present in fababeans have been implicated in favism, an anaemic disease of humans. Vicine and convicine concentrations are reduced by growth of Lactobacillus plantarum on fababean suspensions. The glycosides are eliminated from the fababean substrate by the growth of the filamentous fungus Fusarium graminearum. Incubation of fababean suspension with concentrated culture filtrate of Aspergillus oryzae, induced for extracellular beta-glucosidase production, results in complete degradation of the glycosides. This study suggests a potential use of micro-organisms or microbial enzymes for detoxification of fababeans.

Topics: Aspergillus oryzae; beta-Glucosidase; Electrophoresis; Fabaceae; Favism; Fusarium; Glucosides; Humans; Hydrolysis; Lactobacillus; Plants, Medicinal; Pyrimidinones; Uridine

Vicine and convicine as natural occurring toxic compounds in Vicia faba are involved in the formation of hemolytic anemia (favism). Removal of these compounds needs high technological expense. Microbiological degradation with different strains of bacteria was tried. After 3 h incubation with Streptococcus faeciens convicine was converted completely and Vicine to about 95%.

Topics: Biodegradation, Environmental; Escherichia coli; Fabaceae; Flour; Food Microbiology; Glucosides; Lactobacillus; Lactobacillus acidophilus; Plants, Medicinal; Pyrimidinones; Streptococcus; Toxins, Biological; Uridine

The effects of GSH on the autoxidation of the fava bean pyrimidine aglycones, divicine and isouramil, and on acid-hydrolyzed vicine (provisional identification 2-amino-4,5,6-trihydroxypyrimidine) have been studied. GSH alone promoted redox cycling of each compound, with concomitant GSH oxidation and H2O2 production. In the presence of superoxide dismutase, there is a lag period during which little pyrimidine oxidation occurs, followed by a period of accelerated oxidation. With the three pyrimidines, increasing concentrations of GSH extended this lag period and progressively decreased subsequent rates of both pyrimidine oxidation and O2 uptake. No GSH oxidation or O2 uptake occurred during the lag. These results show that the combination of GSH and superoxide dismutase is able to inhibit redox cycling of the pyrimidines. With a 10-fold excess of GSH over isouramil or acid-hydrolyzed vicine (20-fold with divicine) this coupled oxidation of GSH and the pyrimidine is almost completely suppressed. This mechanism may be a means whereby GSH in combination with superoxide dismutase protects against the cytotoxic effects of these reactive pyrimidines.

Topics: Barbiturates; Catalase; Glucosides; Glutathione; Hydrogen Peroxide; Hydrogen-Ion Concentration; Kinetics; Oxidation-Reduction; Oxygen Consumption; Pyrimidinones; Superoxide Dismutase

Release of iron from ferritin by the polyhydroxypyrimidines, dialuric acid, isouramil, divicine, and acid-hydrolyzed vicine, was measured. Iron was released at fast initial rates which gradually declined to zero in 10 min. All the compounds were better reductants for ferritin-iron under nitrogen than in air. The effects of superoxide dismutase, catalase, and glutathione on both initial rates and total iron released over 30 min in air were determined. Major effects were inhibition by superoxide dismutase for divicine and isouramil and enhancement for dialuric acid and acid-hydrolyzed vicine. Glutathione promoted increased iron release that was further enhanced by superoxide dismutase. These increases were particularly striking over the longer time period. Catalase, in all cases, gave modest enhancement. Enhanced iron release correlated with inhibition of pyrimidine oxidation. The results indicate that the reduced form of each pyrimidine releases ferritin iron directly, and the effects of the antioxidants are mainly to maintain or regenerate the reduced pyrimidines. A combination of each pyrimidine and ferritin caused peroxidation of phopholipid liposomes, above that seen with the pyrimidines and adventitious iron. Glutathione, superoxide dismutase, and catalase modulated lipid peroxidation in a way consistent with their effects being mainly on ferritin-iron release. On the basis of our findings, we propose that the release and subsequent reactions of ferritin-iron may contribute to the toxicity of these compounds. Although glutathione and superoxide dismutase together efficiently inhibit redox cycling and H2O2 production from the pyrimidines, this combination maximized iron release from ferritin and ferritin-dependent lipid peroxidation.

Topics: Barbiturates; Catalase; Ferritins; Glucosides; Glutathione; Iron; Kinetics; Lipid Peroxidation; Liposomes; Oxidation-Reduction; Oxygen Consumption; Pyrimidines; Pyrimidinones; Superoxide Dismutase

Vicine is a glucoside from broad beans (Vicia faba) that is hydrolyzed upon ingestion to the unstable aglycon divicine, the autoxidation of which has been implicated in the onset of hemolysis in favism,possibly via production of superoxide and hydrogen peroxide. The autoxidation of divicine proceeds through a series of reactions involving the formation of a radical species. In this study divicine radicals were produced either by incubation of vicine with beta-glucosidase or by boiling vicine in hydrochloric acid. On the basis of electron spin resonance spectra, it was shown that the two treatments produce different radicals. By spectral simulation the acid-produced radical was demonstrated to be a deaminodivicine. The autoxidation rates of the two radicals were determined from the disappearence of their electron spin resonance signals in the presence of air: at physiological pH the enzymatically produced divicine radical was much more stable to oxygen than the chemically produced radical. The two radicals may thus be expected to behave differently in a biological system. The repercussions of these findings could be considerable, given that most of the pharmacological and biochemical studies on vicine action have been done with the chemically produced compound, which is shown here to be an unphysiological intermediate.

Topics: Cellulases; Electron Spin Resonance Spectroscopy; Free Radicals; Glucosides; Hydrolysis; Pyrimidinones; Vicia faba

The response of faba bean 'Vicia faba' (Giza 2 variety) towards soaking conditions differed greatly since the absorbed quantities of water (either by the whole or the decorticated forms) are a function of their chemical constituents. On the other hand, 28.45% of the total vicine (vicine & convicine) present in the whole faba bean samples was extracted after soaking for 72 h at room temperature. Subsequently, other soaking mediums, i.e., 0.5% sodium carbonate and/or 1% acetic acid were used in an attempt to increase the level of vicine elimination. Percentage removal of total vicine in whole faba bean was higher in the acidic (61.31%) than the alkaline (38.40%) medium under the conditions tested, i.e., at room temperature for 72 hours. The rates of vicine + convicine elimination in decorticated faba bean for the acidic acid and alkaline soaking media were 78.46 and 79.13%, respectively. The solubility ratio of total vicine relative to soaking solutions (H2O:Na2CO3:Acetic acid) was 1:1.35:2.16 in the whole broad bean and 1:2.41:2.39 in the decorticated samples. The residual amounts of total vicine (78.33% and 77.27%) present after stewing under normal and under pressure cooking conditions could be expected to be decreased to 30.33% for the former and 29.92% for the later after 72 h of soaking. Regression analysis was used to estimate the theoretical zero point of vicine elimination from faba bean through soaking in 1% acetic acid.

Topics: Cooking; Egypt; Fabaceae; Favism; Glucosides; Glycosides; Plants, Medicinal; Pyrimidinones; Water

Field beans (faba beans, broad beans, horse beans, ackerbohnen, Vicia faba L.) depress weight of eggs when fed to laying hens. Vicine isolated from field beans has been shown to depress egg weight and hatchability when fed in large amounts. The present study was undertaken to determine the effect of using three varieties of field beans, varying in tannin and total vicines content, at 20% in breeder diets on reproductive performance of hens and associated vicine transfer from the diet to the egg. Data on egg production, feed consumption, egg weight, body weight, egg quality, hatchability, and hen blood chemistry were obtained. Direct spectrophotometric and high pressure liquid chromatographic (HPLC) analyses of field beans, egg albumen, and egg yolk were conducted. Performance of the hens was excellent on all production characteristics except that there was a nonsignificant reduction in egg weight, a significant reduction in egg shell thickness for hens fed all three types of field beans, and a highly significant reduction in hatchability of eggs from hens fed one but not the other two sources of field beans. The hatchability effect was not correlated with vicine or tannin content of the field beans and only traces of vicine were transferred to the egg by the hen from the diet. Although larger amounts of vicine depressed hatchability when injected into fertile eggs, the trace amounts found in eggs from feeding field beans did not account for the reduction in hatchability observed in this study. It is possible that the hydrolysis product of vicine, divicine or the analogous product from convicine, isouramil, or both, may be involved in toxicity, because these substances are known to be the cause of a hemolytic anemia in some humans that suffer from favism due to consumption of field beans.

Topics: Animal Feed; Animals; Chickens; Fabaceae; Female; Fertility; Glucosides; Glycosides; Oviposition; Plants, Medicinal; Pyrimidinones

Topics: Animals; Glucosides; Glycosides; Hydrolysis; Intestinal Absorption; Male; Pyrimidinones; Rats; Rats, Inbred Strains; Uracil; Uridine

Aqueous extracts of a different variety of fresh broad bean seeds obtained from a favism endemic area in Turkey, were incubated with blood from sensitive and non-sensitive (control) subjects. Red blood cells were characterized by a whole blood glutathione (GSH) and a deficiency of Glucose-6-phosphate dehydrogenase (G-6-PD) activity. As the decrease in GSH percent is taken as an index of haemolytic activity, the test results were as following: Sakiz , Milas -Region, French broad bean extracts reduced the blood GSH levels 48%, 70%, 46% and 53%, respectively, in favism sensitive subjects. Active principles which are responsible for the haemolysis ( Vicine and Convicine ) were isolated from broad beans and their effects on GSH levels of blood were 99% and 81%, respectively, in favism sensitive subjects and 33.3% and 19% in normal subjects.

Topics: Fabaceae; Favism; Glucosides; Hemolysis; Humans; In Vitro Techniques; Plant Extracts; Plants, Medicinal; Pyrimidinones; Turkey; Uracil; Uridine

A new method for the quantitation of the favism-inducing agents in legumes is described. The procedure involves differential extraction of the glucosides vicine and convicine with acetic acid (25%), followed by an enzymatic hydrolysis by beta-glucosidase under anaerobic conditions. Each of the aglycone moieties, isouramil and divicine, anaerobically reduces two molecules of o-ferriphenanthroline to o-ferrophenanthroline. This reaction is readily followed spectrophotometrically at 515 nm. Using this procedure, it was found that in various strains of Vicia faba, the level of these two glucosides comprises approximately 0.5% of the wet weight of the seeds. In contrast, these glucosides could not be detected in either green peas or chick peas.

Topics: Barbiturates; Fabaceae; Favism; Glucosidases; Glucosides; Oxidation-Reduction; Phenanthrolines; Plants, Medicinal; Pyrimidinones; Spectrophotometry; Uracil; Uridine

Topics: Absorption; Animals; Anti-Bacterial Agents; Cecum; Chickens; Glucosides; Glycosides; Half-Life; Hydrolysis; Intestines; Male; Pyrimidinones; Tissue Distribution; Uracil; Uridine

1. Experiments were conducted to study the effects of dietary vicine (2, 6-diamino-4, 5 dihydroxy pyrimidine-5 (beta-D-glucopyranoside)) and supplemental vitamin E on the performance of laying hens and growing chicks, haemolysis of erythrocytes than birds fed on a control diet. 3. Vicine when fed to laying hens had a very dramatic effect. It depressed food consumption, egg weight, fertility and hatchability of eggs. Packed cell volume and erythrocyte haemoglobin levels and led to increased liver weights, liver glutathione levels, liver and plasma lipid levels, plasma lipid peroxide levels and erythrocyte haemolysis in vitro. Liver protein and plasma vitamin E:lipid levels were not altered. Vitamin E supplementation slightly increased egg weights, markedly improved fertility and hatchability of eggs and lowered liver weights and lipid levels but did not affect the other factors examined. 4. It is concluded that vicine which was isolated from faba beans (Vicia faba L.) has a marked influence on the metabolism of the laying hen and only a slight effect on growing chick. Vicine or its metabolites or both cause peroxidation of cellular components which result in abnormal lipid transport of synthesis or both, increased fragility of erythrocytes, and reduced fertility. These effects are overcome to varying extents by supplemental vitamin E.

Topics: Animals; Chickens; Diet; Feeding Behavior; Female; Fertility; Glucosides; Glycosides; Hemolysis; Lipid Metabolism; Liver; Organ Size; Ovulation; Pyrimidinones; Toxins, Biological; Vitamin E

Topics: Chromatography, High Pressure Liquid; Fabaceae; Favism; Glucosides; Glycosides; Levodopa; Plants, Medicinal; Pyrimidinones; Seeds; Uracil; Uridine

Fava beans contain high amounts (up to 6.7 g/100 g dry weight) vicine and convicine. Their active aglycones divicine and isouramil have equivalent metabolic effects. They rapidly oxidize GSH to GSSG in normal and G6PD-deficient red cells. No regeneration of GSH occurs in deficient cells. The stoichiometry of the divicine oxidation of GSH is 1:1. Ascorbic acid is quickly oxidized by isouramil in both normal and deficient cells but regenerates only in normal cells. Isouramil oxidizes NADH at a much lesser extent than NADPH. Glycolysis is activated at the glyceraldehyde 3-phosphate dehydrogenase step. Divicine strongly stimulates hexone monophosphate shunt only in normal red cells. Divicine alone or associated with ascorbic acid has almost no effect in deficient red cells. Malonyl dialdehyde production is slight and virtually the same in normal and deficient cells treated with 5 mM isouramil. Large polypeptide aggregates are formed after 12 and 24 hours incubation with 1 mM divicine in deficient cells only. Divicine (0.25 mM) markedly decreases the filterability of deficient cells. The results are consistent with a causal role of divicine/isouramil in the genesis of the hemolytic crisis occurring in G6PD-deficient subjects after fava bean ingestion.

Topics: Ascorbic Acid; Barbiturates; Erythrocytes; Favism; Glucosephosphate Dehydrogenase Deficiency; Glucosides; Glutathione; Humans; Kinetics; Pyrimidinones; Reference Values; Species Specificity; Toxins, Biological; Uracil; Uridine

Covicine + vicine, L-DOPA-glucoside + L-DOPA and ascorbic acid were determined in different lines of Vicia faba beans throughout the biological cycle of the plant. As the seed matures the levels of convicine + vicine as well as of ascorbic acid decrease with seed maturation in all the lines examined. L-DOPA, which is lacking in cotyledons but present in the tegument, also decrease and is nearly undectable in some lines with white flowers.

Topics: Ascorbic Acid; Fabaceae; Favism; Glucosides; Hemolysin Proteins; Levodopa; Plants, Medicinal; Pyrimidinones; Seeds; Uracil; Uridine

Topics: Animals; Chickens; Eggs; Fabaceae; Female; Glucosides; Glycosides; Plants, Medicinal; Pyrimidinones; Toxins, Biological

Topics: Fabaceae; Glucosides; Glycosides; Methods; Plant Proteins; Plants, Medicinal; Pyrimidinones

Topics: Favism; Glucosephosphate Dehydrogenase; Glucosides; Humans; In Vitro Techniques; NADP; Pyrimidinones

Topics: Favism; Glucosides; Glycosides; Humans; Pyrimidinones

Topics: Chemistry, Pharmaceutical; Glucosides; Humans; Pyrimidines; Pyrimidinones

Topics: Glucosides; Humans; Pyrimidines; Pyrimidinones