Analysis of the monosaccharide components in Angelica polysaccharides by high performance liquid chromatography.

An analytical method of on-line high performance liquid chromatography (HLPC) was developed to simultaneously separate and identify the monosaccharide composition of three Angelica polysaccharide fractions (APF), named APF1, APF2 and APF3. In this method, APF were hydrolyzed into component monosaccharides and subsequently labeled with 1-phenyl-3-methyl-5-pyrazolone (PMP), and then the labeled monosaccharide derivatives were separated by a reverse-phase C18 column and monitored by UV absorbance at 250 nm. The results showed that nine monosaccharide derivatives have been well separated by HPLC under optimized conditions and the composition analysis of monosaccharides from APF samples could be achieved using acid hydrolysis and a set of monosaccharide standards. With this method, the within-day and day to day precisions of the composition determinations were 3.41-4.87% and 3.12-4.93% (RSD), respectively. The method was successfully applied to the determination of the component monosaccharides of Angelica polysaccharides.     

Synthesis of tri-, hexa-, and nonasaccharide subunits of the atypical O-antigen polysaccharide of the lipopolysaccharide from Danish Helicobacter pylori strains

Synthesis of trisaccharide repeating unit, -->3)-alpha-D-Rhap-(1-->2)-alpha-D-Manp3CMe-(1-->3)-alpha-L-Rha p-(1-->, and its dimeric hexa- and trimeric nonasaccharide subunits of the atypical O-antigen polysaccharide of the lipopolysaccharide from Danish H. pylori strains D1, D3, and D6 has been accomplished. Successful synthesis of the hexasaccharide and the nonasaccharide was possible by dimerization and trimerization of the suitably protected trisaccharide repeating unit, in which three monosaccharide moieties were arranged in a proper order by placing the sterically demanding 3-C-methyl-D-mannose moiety in between D- and L-rhamnoses. Key steps include the coupling of three monosaccharide moieties and dimerization and trimerization of the trisaccharide unit by glycosylations employing the 2'-carboxybenzyl glycoside method. Also presented is a method for the synthesis of the novel branched sugar, 3-C-methyl-D-mannose moiety by elaboration of its equatorial hydroxyl and axial methyl groups at C-3' in the disaccharide stage.     

Solid-phase synthesis of bleomycin A(5) and three monosaccharide analogues: exploring the role of the carbohydrate moiety in RNA cleavage

The solid-phase synthesis of bleomycin A5 (BLM A5) and three monosaccharide analogues is presented. The monosaccharide analogues incorporated alpha-d-mannose, alpha-l-gulose, and alpha-l-rhamnose moieties in lieu of the disaccharide normally present in BLM A5. Also explored were the abilities of each of the monosaccharide congeners to cleave a 53-nt RNA. The elaboration of these carbohydrate-modified bleomycin analogues helps to define the role of the disaccharide moiety during the RNA cleavage event. The relatively facile solid-phase synthesis of bleomycin A5 and each of the carbohydrate analogues constitutes an important advance in the continuing mechanistic studies of bleomycin.     

The effect of monosaccharides on self-assembly of benzenetricarboxamides

In this work, three common monosaccharides, glucose, galactose and mannose, are employed to investigate the effect of monosaccharide on the self-assembly of benzenetricarboxamide (BTA) core-containing molecules. Based on the effect of monosaccharides, three benzenetricarboxamide derivatives aggregate into different ordered structures, i.e., vesicles, nanorings and fibers. When alanine linkers are introduced to these molecules between the core and the monosacchride, all monosaccharide-based BTAs aggregate into irregular morphologies, meanwhile they become similar with the increase of the length of alanine linkers indicating the disappearance of the monosaccharide effects.     

Utilization of MS3 spectra for the multicomponent quantification of diastereomeric N-acetylhexosamines

A rapid and accurate means of quantifying mixtures of diastereomeric N-acetylhexosamine monosaccharides using MS³ product ions is introduced. The method involves derivatizing the monosaccharides with [Co(DAP)₂Cl₂]Cl (where DAP is diaminopropane), and subjecting the derivatized products to collision-induced dissociation (CID) in a quadrupole ion trap mass spectrometer. Each diastereomer provides unique MS³ product ion abundances. The abundances for the pure monosaccharide standards are used in a system of equations in order to quantify mixtures of these diastereomers. Using the system of equations is quite advantageous, as it is the only mass spectrometric method that has been shown to successfully quantify mixtures of more than two isomers. The utility of the method is demonstrated by successfully quantifying various two and three component mixtures of the diastereomeric monosaccharides. Furthermore, the method is used to quantify the recovery of a single diastereomeric monosaccharide from an acidic resin. Although the multicomponent quantification method described herein is used to quantify mixtures of N-acetylhexosamine diastereomers, it could be applied to any group of isomers, provided distinguishing CID spectra are obtained. This is the first known report of utilizing MS³ product ions for quantification of structural isomeric mixtures.     

Hydrophilic interaction chromatography with Fourier transform mass spectrometry of monosaccharide anhydrides

A fast, selective, and sensitive method for the determination of three monosaccharide anhydrides (galactosan, mannosan, levoglucosan), based on hydrophilic interaction chromatography and Fourier transform mass spectrometry, was successfully developed. The simple experimental stationary phase and mass spectrometry performance screening allowed the selection of the best available chromatographic and mass spectrometry conditions. Thus, the chromatographic separation was performed on a highly selective stationary phase containing a zwitterionic phosphorylcholine group and the monosaccharide anhydrides were detected as [M+HCOO]^? adduct in the negative mode. The method showed accuracy in the range of 84–111 and 89–102% with interbatch precision expressed as relative standard deviations of 5.6–15.4 and 5.0–9.0% for the aerosol extract and snow samples, respectively. The limit of quantification in absolute values ranged from 10 to 30 pg, the limit of quantification, expressed as concentration, ranged was 0.3–0.9 ng/m³ for aerosol and 10–20 ng/mL for snow samples. The method was successfully applied for the determination of monosaccharide anhydrides in aerosol and snow samples.     

Utilization of MS spectra for the multicomponent quantification of diastereomeric N-acetylhexosamines

A rapid and accurate means of quantifying mixtures of diastereomeric N-acetylhexosamine monosaccharides using MS³ product ions is introduced. The method involves derivatizing the monosaccharides with [Co(DAP)₂Cl₂]Cl (where DAP is diaminopropane), and subjecting the derivatized products to collision-induced dissociation (CID) in a quadrupole ion trap mass spectrometer. Each diastereomer provides unique MS³ product ion abundances. The abundances for the pure monosaccharide standards are used in a system of equations in order to quantify mixtures of these diastereomers. Using the system of equations is quite advantageous, as it is the only mass spectrometric method that has been shown to successfully quantify mixtures of more than two isomers. The utility of the method is demonstrated by successfully quantifying various two and three component mixtures of the diastereomeric monosaccharides. Furthermore, the method is used to quantify the recovery of a single diastereomeric monosaccharide from an acidic resin. Although the multicomponent quantification method described herein is used to quantify mixtures of N-acetylhexosamine diastereomers, it could be applied to any group of isomers, provided distinguishing CID spectra are obtained. This is the first known report of utilizing MS³ product ions for quantification of structural isomeric mixtures.     

Simultaneous Determination of Levoglucosan,Mannosan and Galactosan at Trace Levels in Snow Samples by GC/MS

A method for the simultaneous determination of levoglucosan, mannosan and galactosan at trace levels in snow samples is reported by using GC/MS. This method is an improvement on previous aerosol studies. The required sample volume for this method is a mere 5.00 mL of melt water. Discrimination of three isomers is analyzed on the basis of different retention time and fragmentation patterns. The limit of detection is 0.070, 0.058 and 0.046 ng mL^?1 ice melt water for three isomers. This method has the advantage of simultaneous determination of three monosaccharide anhydrides at trace concentration levels in small sample volumes. The relatively high extraction efficiency and low limit of detection will facilitate further studies on biomass burning recorded in snow and ice samples.     

毛细管型离子色谱-脉冲安培法检测枸杞多糖的单糖组成

采用ICS-5000毛细管离子色谱仪对枸杞多糖中的10种单糖进行了分离测定.优化了前处理过程中影响多糖水解的酸种类、酸浓度、水解温度和时间等参数,优化条件为使用2 mol/L三氟乙酸溶液在100℃下水解120min,在该条件下,果糖回收率约为50％,其余单糖回收率在84％～104％之间.采用新型淋洗液自动发生装置电解产生淋洗液,Capillary CarborPac PA20色谱柱分离,毛细管安培池检测,10种单糖成分标准曲线线性关系良好,相关系数均大于99.9％;检出限在2.5～75 μg/L之间,为枸杞多糖中单糖组分测定提供了新的可行方法.     

Synthesis, characterization, antibacterial and antifungal evaluation of novel monosaccharide esters

A novel series of 3-(2-furyl)acrylate monosaccharide esters Ia–f and menthyloxycarbonyl monosaccharide esters IIa–f were designed and synthesized. The chemical structures of the target compounds were confirmed by IR, 1H- and 13C-NMR and ESI-MS, and the target compounds were investigated for their in vitro antibacterial and antifungal activities. The antibacterial screening results showed that the 3-(2-furyl)acrylate monosaccharide ester derivatives Ia–f were either inactive or only weakly active against the three Gram-positive bacterial strains tested, whereas the menthyloxycarbonyl monosaccharide ester derivatives IIa–f exhibited higher levels of activity, with compound IIe being especially potent. The results of the antifungal screening revealed that compounds Ib, Ie, IIb and IIc displayed potent in vitro activities, whereas If and IIf showed promising activities against all of the microorganisms tested, with If exhibiting levels of activity deserving of further investigation.     

Studies on the Synthesis of Trisaccharide Analogues of the Antibiotic Moenomycin A

A new approach for the synthesis of moenomycin trisaccharide analogues is reported in which three monosaccharide building blocks are used and allows the introduction of different substituents at the 6‐position of unit E (Scheme 2). Furthermore, a new procedure for the introduction and manipulation of unit F is described (Scheme 3).     

Glycoligands and Co(II) glycocomplexes. Investigation of the variation of the sugar-scaffold on the structure and chirality measured by circular dichroism

Glycoligands using various monosaccharide platforms functionalised by three 2-picolyl groups and coordinated to Co(II) through the bidentate 2-picolyl ether moieties are interesting ligands as they efficiently induce chirality at the cobalt with a fine control of the structure through the central sugar scaffold.     

单糖/双糖对近中性pH下共轭亚油酸囊泡影响的比较

比较了乳糖等3种双糖或核糖等3种单糖及其复配物对近中性范围共轭亚油酸(CLA)形成脂肪酸囊泡(FAV)的影响. 用激光丁达尔效应确定FAV的pH窗口及各相区, 用透射电子显微镜及动态光散射表征其形貌和尺寸, 用浊度法研究了其稳定性, 用等温滴定量热证明各种糖及其复配物与FAV表面的弱非共价键合作用, 并经理论计算获得结合能. 实验和计算结果表明, 各种糖及其复配物均可以双向拓宽CLA形成FAV的pH窗口, 且拓宽其近中性pH窗口的能力按照双糖<单糖≈双糖/单糖≤单糖/单糖的顺序依次增强. 主要归结为单糖在FAV表面的强竞争吸附, 以及双糖可能因多结合位点吸附而减少其自由羟基与环境水分子的缔合作用, 从而影响多羟基小分子依靠自由羟基增强囊泡表面亲水性的效果.     

A CD-Spectroscopic Alternative to Methylation Analysis of Oligosaccharides: Reference Spectra for Identification of Chromophoric Glycopyranoside Derivatives

A microscale method for identifying the monosaccharide units and their linkages in oligosaccharides is presented. Sugar components are identified by UV and CD spectroscopy of chromophoric degradation products. CD spectral data for approximately 150 different glycopyranoside components are provided for use as reference spectra in the identification of unknown derivatives. Procedures for the conversion of oligosaccharides to monosaccharide subunits bearing 4-bromobenzoate and 4-methoxycinnamate chromophores have been developed based on acetolysis/bromination reactions for glycosidic cleavage of per (bromobenzoylated) oligosaccharides. The method offers an alternative means to conventional methylation analysis of oligosaccharides.     

Existence of the Sugar–Bisulfite Adducts and Its Inhibiting Effect on Degradation of Monosaccharide in Acid System

Degradation of fermentable monosaccharides is one of the primary concerns for acid prehydrolysis of lignocellulosic biomass. Recently, in our research on degradation of pure monosaccharides in aqueous SO₂ solution by gas chromatography (GC) analysis, we found that detected yield was not actual yield of each monosaccharide due to the existence of sugar–bisulfite adducts, and a new method was developed by ourselves which led to accurate detection of recovery yield of each monosaccharide in aqueous SO₂ solution by GC analysis. By the use of this method, degradation of each monosaccharide in aqueous SO₂ was investigated and results showed that sugar–bisulfite adducts have different inhibiting effect on degradation of each monosaccharide in aqueous SO₂ because of their different stability. In addition, NMR testing also demonstrated possible existence of reaction between conjugated based HSO₃ ^? and aldehyde group of sugars in acid system.     

Synthesis of monosaccharide units using fluorous method

The efficient synthesis of monosaccharide units, glycosyl acceptor, and donor, by using the fluorous tag method was achieved. Fluorous tag 5 was stable in each reaction condition to the preparation of various monosaccharide units. Each fluorous synthetic intermediate could be obtained in a straightforward manner by a simple fluorous-organic solvent partition.     

Structure-retention index relationships for derivatized monosaccharides on non-polar gas chromatography columns.

A gas chromatographic method for predicting the retention index of a derivatized monosaccharide is presented. The procedures are especially useful to detect and predict minute quantities of sugars in biological or chemical samples. Monosaccharides are first converted to the alditols and then derivatized by acetylation, permethylation or silylation. The derivatized monosaccharide structure-retention index relationship that has been developed is useful in the identification of unknown monosaccharides that can be readily confirmed by gas chromatography-mass spectrometry.     

Dissolution-guided wetting for microarray and microfluidic devices

The trapping of air bubbles presents a substantial impediment for the user in the increasingly widespread use of lab-on-a-chip products having microcavities in the forms of microwells, traps, dead ends and corners. Here we demonstrate a simple, effective, and passive method to eliminate air bubbles by coating hydrophilized microarray and microfluidic devices with a monosaccharide such as d-glucose or D-sorbitol, where the microcavities are filled with a conformal, elliptical, cone-shaped monosaccharide solid. These devices were stored in air for up to 6 months with a complete rewetting of the microcavities by dissolution of the monosaccharide with an aqueous solution.     

Lipids and lipopolysaccharides of the genusFlavobacterium

The fatty acid compositions of the free lipids of three strains and the monosaccharide compositions of the lipopolysaccharides of four strains of new species of microorganisms of the genusFlavobacterium have been studied. The acidic nature of the polysaccharides of the LPSs of the microorganisms studied has been shown.     

An alternative strategy based on ultra-high-performance supercritical fluid chromatography for full monosaccharide compositional analysis of polysaccharides in Schisandra chinensis fruits

Due to green and environment-friendly characteristics, ultra-high-performance supercritical fluid chromatography has been widely used in analytical fields in recent years, but until now few reports are available for monosaccharide compositional analysis of macromolecule polysaccharides. In this study, an ultra-high-performance supercritical fluid chromatography technology with an unusual binary modifier is used to determine the monosaccharide compositions of natural polysaccharides. Each carbohydrate herein is simultaneously labeled as 1-pheny-3-methyl-5-pyrazolone and acetyl-derivative via pre-column derivatizations aiming to increase UV absorption sensitivity and decrease water solubility. Ten common monosaccharides are fully separated and detected on ultra-high-performance supercritical fluid chromatography combined with a photo-diode array detector by systematic optimization of multiple relevant parameters, for example, column stationary phases, organic modifiers, additives, flow rates, and so on. Compared with carbon dioxide as a mobile phase, the addition of a binary modifier increases the resolution of analytes. Additionally, this method has the advantages of small consumption of organic solvent, safety, and being environmental-friendly. It has been successfully applied for full monosaccharide compositional analysis of heteropolysaccharides from Schisandra chinensis fruits. To sum up, a new alternative approach is provided for monosaccharide compositional analysis of natural polysaccharides.