Fructose Derivatives Research Articles

One-Step Synthesis, Crystallography, and Acute Toxicity of Two Boron-Carbohydrate Adducts That Induce Sedation in Mice.

Boronic acids form diester bonds with cis-hydroxyl groups in carbohydrates. The formation of these adducts could impair the physical and chemical properties of precursors, even their biological activity. Two carbohydrate derivatives from d-fructose and d-arabinose and phenylboronic acid were synthesized in a straightforward one-step procedure and chemically characterized via spectroscopy and X-ray diffraction crystallography. Additionally, an acute toxicity test was performed to determine their lethal dose 50 (LD50) values by using Lorke's method. Analytical chemistry assays confirmed the formation of adducts by the generation of diester bonds with the β-d-pyranose of carbohydrates, including signals corresponding to the formation of new bonds, such as the stretching of B-O bonds. NMR spectra yielded information about the stereoselectivity in the synthesis reaction: Just one signal was found in the range for the anomeric carbon in the 13C NMR spectra of both adducts. The acute toxicity tests showed that the LD50 value for both compounds was 1265 mg/kg, while the effective dose 50 (ED50) for sedation was 531 mg/kg. However, differences were found in the onset and lapse of sedation. For example, the arabinose derivative induced sedation for more than 48 h at 600 mg/kg, while the fructose derivative induced sedation for less than 6 h at the same dose without the death of the mice. Thus, we report for the first time two boron-containing carbohydrate derivatives inducing sedation after intraperitoneal administration. They are bioactive and highly safe agents. Further biological evaluation is desirable to explore their medical applications.

The Bay Leaves Active Compounds and Its Lipid Oxidative Inhibition Activity in Bulk Cooking Oil

Cooking oil is one of the basic human needs. Improving the quality of bulk cooking oil is necessary because it is related to economic reason. The bulk cooking oil have a lower price than brand package oil, of course. Based on these reasons, research is needed on the use of antioxidants to improve the quality of bulk cooking oil. This study aims to identify the phytochemicals of bay leaves extract through TOF profiling, analysis of iodine number and acid number of bay leaves extract against bulk cooking oil. TOF profiling was carried out to see whether bay leaves had chemical compounds that supported antioxidant activity which had an impact on the inhibition of fat oxidation. The research consisted of 4 stages: 1) extraction and fractionation of bay leaves, 2) TOF profiling of bay leaves extract, 3) application of bay leaves extract to bulk cooking oil, 4) analysis of iodine and acid numbers. Profiling TOF of the bay leaves extract showed 3 peaks : C6H13NO5 (cyclohexanol, galactose, and fructose derivatives), C11H14O5 (pyran and furan), andC11H19NO3 (morpholine derivate). According to SNI, the acid value maximum 0.6 mg KOH/g. Iodine value minimum is 45 g I2/ 100 mL (SNI 3741 : 2013). Based of this data standart, this study recommended use bay leaves extract in concentration 0.80%. The addition of bay leaves extract as much as 0.80% showed an iodine number of 48.2 g I2/100 mL and an acid number of 0.34 mg KOH/g where the positive control TBHQ showed an iodine number of 48.7 g I2/100 mL and an acid number of 0.19 mg KOH/g.

Microwave-assisted liquefaction of carbohydrates for 5-hydroxymethylfurfural using tungstophosphoric acid encapsulated dendritic fibrous mesoporous silica as a catalyst

Tungstophosphoric acid (TPA) encapsulated dendritic fibrous silica KCC-1 was prepared via a microemulsion system with the simple reflux method using cetyltrimethylammonium bromide as a structure-directing agent. The TPA impregnated on KCC-1 (ITPA-KCC-1) was also prepared for comparative. Various physicochemical techniques were used to characterize the synthesized materials and their activity evaluated in the 5-hydroxymethylfurfural (HMF) formation from carbohydrates derivatives of fructose, glucose and cellulose. The effect of various factors such as catalyst to substrate ratio, different solvents and temperature were investigated on the formation of HMF. The resultant encapsulated catalyst was very active in fructose dehydration with the yield of 92% HMF and full conversion of fructose at 120 °C for 30 min under the microwave heating condition without any salt additive in the THF solvent system as well as 95% in MIBK solvent. The HMF yield was achieved by 58% and 16.2% from glucose and cellulose in the DMSO solvent, respectively. The TPA-KCC-1 can be separated easily after reaction from the reaction mixture and reused atleast five times without substantial loss in catalytic activity. This study provides an easy encapsulation method for TPA in dendritic fibrous silica KCC-1 as a heterogeneous catalyst, and it should have great application potential in other biomass valorization processes.

Isolation and Identification of Bioactive Compounds from the Tuber of Brassica oleracea var. gongylodes

Brassica oleracea var. gongylodes (red kohlrabi) is a biennial herbaceous vegetable whose edible bulbotuber-like stem and leaves are consumed globally. Sliced red kohlrabi tubers were extracted using methanol and the concentrated extract was partitioned successively with dichloromethane (CH2Cl2), ethyl acetate (EtOAc), n-butanol (n-BuOH) and water (H2O). Repeated column chromatography of EtOAc fraction through silica, sephadex LH-20 and RP-18 gel led to isolation of eleven compounds of which compound 1 was a new glycosylated indole alkaloid derivative, 1-methoxyindole 3-carboxylic acid 6-O-β-D-glucopyranoside. Others were known compounds namely, β-sitosterol glucoside (4), 5-hydroxymethyl-2-furaldehyde (5), methyl-1-thio-β- D-glucopyranosyl disulfide (6), 5-hydroxy-2-pyridinemethanol (7), (3S,4R)-2-deoxyribonolactone (8), n-butyl-β- D-fructopyranoside (9), uridine (10) and three fructose derivatives, D-tagatose (11), β-D-fructofuranose (12) and β-D-fructopyranose (13). Similarly, isolation from CH2Cl2 fraction gave two known indole alkaloids, indole 3- acetonitrile (2) and N-methoxyindole 3-acetonitrile (3). The structure elucidation and identification of these compounds were conducted with the help of 13C and 1H NMR, HMBC, HMQC, EIMS, HR-ESIMS and IR spectroscopic data, and TLC plate spots visualization. Compounds 2, 3, 4, 5, 6, 7, 8 and 9 are noted to occur in kohlrabi for the first time. Different bioactivities of these isolated compounds have been reported in literature.

Estimation of the iron bioavailability in green vegetables using an in vitro digestion/Caco-2 cell model

It is estimated that over 30% of the global population is anaemic, half of which is due to iron deficiency. The bioavailability of iron from vegetables is low and variable, and influenced by food composition and matrix. We have therefore determined the relative bioavailability of iron in five types of green vegetable, spinach, broccoli, savoy cabbage, curly kale and green pepper, by measuring the ferritin response in a simulated digestion/Caco-2 cell model. Savoy cabbage gave the highest ferritin response and analysis of the digest showed that the iron was present in low molecular weight fractions which contained glucose, fructose, organic acids and amino acids. The addition of fructose 1,6-biphosphate to the Caco-2 cells increased iron uptake 2-fold. These results demonstrate that cabbage was the best source of bioavailable iron out of the vegetables studied and suggest that the formation of complexes with fructose derivatives contribute to increase the iron bioavailability.

Enhanced production of fructose ester by biocatalyzed continuous flow process

Abstract Background Fatty acid sugar esters are non-toxic, odorless, non-irritanting surfactants. They can be synthesized by renewable resources and are completely biodegradable in aerobic and anaerobic conditions. Their application has been expanded in innumerous areas including pharmaceuticals, cosmetics, detergents and food industry. Lipase-catalyzed esterification have been investigated as a potential substitute to the traditional chemical, demanding milder reaction conditions, allowing better reaction control and providing higher-quality products. So, the lipase catalyzed sugar ester synthesis becomes an interesting strategy for producing biodegradable, non- ionic surfactants. The main disadvantage of this protocol is the poor solubility of substrates and long reaction time required for performed the esterification reaction with moderated to good yields. Results Here in, we report the enzymatic esterification of steric hindered fructose derivative with free fatty acids derived from palm oil refining process (RePO) under continuous flow conditions at concentrations up to 0.5 M, increasing the productivity up to 100 mg. min −1.g immob. enzyme −1. Conclusions The immobilized commercial enzyme from Rhizomucor miehei generated the best performance between the catalysts tested.

An efficient procedure for synthesis of fructose derivatives

We developed a very simple procedure to prepare fructose derivatives or fructosides. This procedure waived the requirement of isomer separation, which is usually a very common and difficult problem in fructose derivative syntheses. In this procedure, the hydroxyl groups were differentiated to expedite the preparation of many kinds of other fructose derivatives and the alkoxy group in the fructosides could exchange easily with alcohols under the mild acidic condition, which offered a new method to synthesize other fructosides through alcohol exchanging. By using this procedure, we successfully synthesized fluorogenic fructose derivatives for high throughput enzyme screening. This methodology could expand the usage of the abundant fructose in organic synthesis.

Lipase-catalyzed esterification of steric hindered fructose derivative by continuous flow and batch conditions

The lipase catalyzed sugar ester synthesis is an interesting strategy for producing biodegradable, non-ionic surfactants. The main disadvantage of this protocol is the long reaction time required for achieving moderated to good yields. Here, we report the esterification of steric hindered fructose derivative where important variables for batch conditions were identified by the use of a RSM protocol and then translated to the continuous flow regime with high conversions and short residence times.

Thermal decomposition of monosaccharides derivatives applied in ceramic gelcasting process investigated by the coupled DTA/TG/MS analysis

The paper reports the decomposition of saccharides derivatives in comparison to commercial substances during the process of binder removal from ceramic samples. The saccharides derivatives are polymers synthesized from glucose and fructose with acryloyl group in the sugar molecule. The synthesized compounds played the role of binder in the shaping of ceramic powders by gelcasting method. The method belongs to colloidal processes and allows to produce ceramic elements of complicated geometry. As ceramic powder Al2O3 was used. The thermal analysis have been done on apparatus coupled with mass spectrometer. MS analysis showed what types of gasses are released to the atmosphere during the thermal decomposition of polymers. The obtained results showed important differences in decomposition of polymers obtained from commercial acrylamide, 2-hydroxyethyl acrylate and N,N′-methylenebisacrylamide in comparison to synthesized glucose and fructose derivatives. The measurements allowed to establish the sintering program of the green ceramic samples and evaluate whether harmful NO x gases are released to the atmosphere.

Preparation, water solubility and antioxidant activity of branched-chain chitosan derivatives

Water-solubility at neutral or basic pH of chitosan was largely improved by specific attachment of carbohydrates to the 2-amino functions achieved by Maillard reaction or further reductive alkylation of Schiff bases. The characteristic physicochemical, rheological properties, and antioxidant activities of the derivatives were investigated. Experimental results indicated that the solubility of all the chitosan-saccharides before and after reducing had been greatly enhanced comparing to the native chitosan. The Schiff base typed chitosan–fructose derivative was highest at 13.2 g/L of all, and Schiff base typed chitosan derivatives existed better solubility, Ph stability and more effective scavenging activity against DPPH radical than N-alkylated chitosan derivatives. The degree of substitution (DS) of the chitosan derivatives increased with higher concentration of saccharide, increasing reaction time and temperature. The reduction of viscosity of chitosan derivatives decreased with increasing reaction time and temperature. The results suggest that the water-soluble chitosan derivatives produced through Maillard reaction may be promising commercial additive in cosmetics and food.

Measurement of glucose and fructose in clinical samples using gas chromatography/mass spectrometry

Objective: The impact of increased fructose consumption on carbohydrate metabolism is a topic of current interest, but determination of serum level has been hindered due to low concentration and interference from serum glucose. We are reporting a method for the quantification of glucose and fructose in clinical samples using gas chromatography/mass spectrometry (GC/MS). The accuracy and precision of GC/MS and an enzymatic assay were compared. Design and methods: Mass spectrometry fragmentation patterns of methyloxime peracetate derivatized aldose and ketose were determined. Unique fragments for glucose and fructose were used for quantitative analysis using isotope labeled recovery standards. Results: Methyloxime peracetate derivatives of glucose and fructose showed characteristic loss of acetate (M-60) or ketene (M-42) under chemical ionization (CI). Under electron impact (EI) ionization, a unique C1–C2 fragment of glucose was formed, while a C1–C3 fragment was formed from keto-hexoses. These unique fragments were used in the quantitative assay of glucose and fructose in clinical samples. In clinical samples, the GC/MS assay has a lower limit of detection than that of the enzymatic assay. In plasma samples from patients evaluated for diabetes the average serum glucose and fructose were 6.19 ± 2.72 mM and 46 ± 25.22 μM. Fructose concentrations in many of these samples were below the limit of detection of the enzymatic method. Conclusion: Derivatization of aldose and ketose monosaccharides to their respective O-methyloxime acetates for GC/MS analysis is a facile method for determination of serum/plasma glucose and fructose samples.

Identification of free disaccharides and other glycosides in wine

Free soluble carbohydrates of different wine samples were analyzed by GC–MS as their trimethylsilyloximes using a methylsilicone column. Besides α,α-trehalose, several β-glucosylglucoses such as cellobiose, sophorose, laminaribiose and gentiobiose were the main disaccharides identified. With the exception of gentiobiose, these disaccharides are now reported for the first time in wine. Lactose (4-O-β- d-galactopyranosyl- d-glucose), previously described in this product, was also tentatively identified. Several free glycosides: β-ethyl-glucoside and seven glyceryl-glycosides (including glucosides and galactosides) were also identified for the first time in wine. On the contrary, disaccharides in grape juice were mainly constituted of fructose derivatives, including sucrose, and no glycosides were detected. Although the total amount of disaccharides was different in white wines (<50 mg/L) from those in rosé and red wines (80–130 mg/L), the chromatographic profile was noticeably similar in all wine samples. The method here reported allows the identification of several carbohydrates which have not been previously detected in wines and could contribute to increase the understanding of enzymatic activity during winemaking.

Fluorescent Fructose Derivatives for Imaging Breast Cancer Cells

Breast cancer cells are known to overexpress Glut5, a sugar transporter responsible for the transfer of fructose across the cell membrane. Since Glut5 transporter is not significantly expressed in normal breast cells, fructose uptake can potentially be used to differentiate between normal and cancerous cells. Fructose was labeled with two fluorophores at the C-1 position: 7-nitro-1,2,3-benzadiazole (NBD) and Cy5.5. The labeling site was chosen on the basis of the presence and substrate specificity of the key proteins involved in the first steps of fructose metabolism. Using fluorescence microscopy, the uptake of the probes was studied in three breast cancer cell lines: MCF 7, MDA-MB-435, and MDA-MB-231. Both fluorescent fructose derivatives showed a very good uptake in all tested cell lines. The level of uptake was comparable to that of the corresponding glucose analogs, 2-NBDG and Cy5.5-DG. Significant uptake of 1-NBDF derivative was not observed in cells lacking Glut5 transporter, while the uptake of the 1-Cy5.5-DF derivative was independent of the presence of a fructose-specific transporter. While 1-NBDF showed Glut5-specific accumulation, the coupling of a large fluorophore such as Cy5.5 likely introduces big structural and electronic changes, leading to a fructose derivative that does not accurately describe the uptake of fructose in cells.

Synthesis and antihyperlipidemic activity of novel glycosyl fructose derivatives

A series of novel di and trisaccharide derivatives containing d-fructose moiety at the reducing end have been synthesized and evaluated for their antihyperlipidemic activity in hyperlipidemic hamster model. Among 11 glycosyl fructose derivatives five compounds showed potent antihyperlipidemic activity either by enhancing high-density lipoprotein (HDL) cholesterol concentration and/or lowering triglyceride (TG) level.

Practical Synthesis of Shi′s Diester Fructose Derivative for Catalytic Asymmetric Epoxidation of Alkenes.

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Spacer-Mediated Synthesis of Contra-Thermodynamic Spiroacetals: Stereoselective Synthesis of C2-Symmetric Difructose Dianhydrides

The xylylene moiety (ortho, meta, and para) was employed as a rigid tether in the spacer-mediated synthesis of difructose dianhydrides (DFAs), a unique class of bis-spiroacetal derivatives present in food products. The synthetic methodology exploits the suitability of triflic acid to promote spirocyclization in organic solvents under irreversible reaction conditions, using anomeric isopropylidene fructose derivatives as precursors. Advantage was taken of the strong dependence of the conformational properties of DFAs on the relative configuration of the spiroketal centers. Highly stereoselective syntheses of the contra-thermodynamic difructofuranose and difructopyranose diastereomers, namely the C2-symmetric derivatives having the beta-configuration at both anomeric centers, have been accomplished by judicious choice of the xylylene positional isomer and of the linking position to the fructose building blocks. Interestingly, the rigid spacer concept has also been implemented to favor intermolecular processes leading to higher macrocyclic architectures that incorporate the bis-spiro fructodisaccharide subunit.

Practical Synthesis of Shi's Diester Fructose Derivative for Catalytic Asymmetric Epoxidation of Alkenes

[reaction: see text] A practical synthesis of Shi's diester 3 for catalytic asymmetric epoxidations has been developed. The catalyst has been prepared in multigram quantities from D-fructose in four steps with a 66% overall yield. Efficiency, cost, and selectivity aspects of the reagents involved for its preparation have been taken care of during its preparation. The workup procedures have been simplified to the bare minimum, rendering a very practical preparation method. The well-known high efficiency of this catalyst 3 in the epoxidation of alpha,beta-unsaturated carbonyl compounds has also proved to be high in unfunctionalized alkenes.

Synthesis, cytotoxicity, cellular uptake and influence on eicosanoid metabolism of cobalt–alkyne modified fructoses in comparison to auranofin and the cytotoxic COX inhibitor Co-ASS

Propargylhexacarbonyldicobalt complexes with fructopyranose ligands were prepared and investigated for cytotoxicity in the MCF-7 human breast cancer cell line. The antiproliferative effects depended on the presence of isopropylidene protecting groups in the carbohydrate ligand and correlated with the cellular concentration of the complexes. IC(50) values of > 20 microM demonstrated that the fructose derivatives were only moderately active compared to the references auranofin and the aspirin (ASS) derivative [2-acetoxy(2-propynyl)benzoate]hexacarbonyldicobalt (Co-ASS). In continuation of our studies on the mode of action of cobalt-alkyne complexes we studied the influence of the compounds on the formation of 12-HHT (COX-1 product) and 12-HETE (12-LOX product) by human platelets as an indication of the interference in the eicosanoid metabolism, which is discussed as a target system of cytostatics. Co-ASS was an efficient COX-1 inhibitor without LOX inhibitory activity and auranofin inhibited both COX-1 and 12-LOX eicosanoid production. The missing activity of the fructopyranose complexes at the 12-LOX and the only moderate effects at COX-1 indicate that COX/LOX inhibition may be in part responsible for the pharmacological effects of auranofin and Co-ASS but not for those of the fructopyranose complexes.

Synthesis of Carba-β-l-Fructopyranose and Carbacyclic Analogs of Topiramate, an Anticonvulsant Agent

We have prepared carba-β-l-fructopyranose (3) starting from (1S,2R)-1,2-dihydroxycyclohexa-3,5-diene-1-carboxylic acid (5). In addition, an unsaturated derivative bearing a double bond in the ring (viz. 4) was prepared. These l-carbacyclic derivatives of fructose were converted to the corresponding analogs of topiramate, a novel anticonvulsant agent currently in clinical practice.

Iodomethyl group as a hydroxymethyl synthetic equivalent: application to the syntheses of D-manno-hept-2-ulose and l-fructose derivatives.

The one-carbon elongation of aldoses to ketoses using iodomethyllithium as the key reagent in the homologation step is exemplified by the preparation of two carbohydrates of chemical and biological interests: d-manno-hept-2-ulose from d-mannose and l-fructose from l-arabinose.