Structural-fingerprinting of polysaccharides to discern Panax species by means of gas-liquid chromatography and mass spectrometry.

In this paper, a sequential gas-liquid chromatography and mass spectrometry route was proposed for characterization of polysaccharides in Panax ginseng (PG), P. notoginseng (PN), and P. quinquefolius (PQ). Due to the reflection of stepped structure parameters, the resulting integrative profiles were tentatively defined as structural-fingerprinting of polysaccharides (SFP) with monosaccharide compositional fingerprinting (MCF), Smith degradation and non-degradation fingerprinting (SDF and SNF), and oligosaccharide compositional fingerprinting (OCF). The MCF, OCF and SDF did not allow for visual discrimination of the three species due to the high interspecific similarity of PG and PQ, whereas SNF could intuitively distinguish PG, PN, and PQ by the presence or absence of Rha and the peak area ratio of Glc/Gal. Similarity analysis, heatmap analysis and principal component analysis were further performed to discern three Panax species based on SNF data sets. The linear →4)-Hexp-(1 â†’ structures were clearly identified as the common structural backbones in side chains or smooth regions of the main chain in PPG, PPN, and PPQ using HILIC-UHPLC-ESI--MS/MS for characterization of partial acid hydrolyzates. The experimental results displayed that the established SFP approach possesses high comprehensibility as well as satisfactory generalization capability for analysis of plant polysaccharides.

Chemical structure and inhibition on α-glucosidase of polysaccharide with alkaline-extracted from glycyrrhiza inflata residue.

A new neutral polysaccharide, named AGP, was extracted from glycyrrhiza residue by 5% NaOH alkaline solution and purified by DEAE-celluloseand Sephadex G-150. A single and symmetrical peak was shown by HPLC, indicating that AGP is a homogeneous polysaccharide with a molecular weight of 2.89 × 103 KDa. Thespecific rotation of AGP was detected by a polarimeter and it was +45°. Monosaccharide composition analysis indicated that AGP was consisted of l-rhamnose: l-arabinose: d-xylose: d-mannose: d-glucose and d-galactose with a molar ratio of 1:2.33:2.85:0.69:3.05:1.54. The structure of AGP was analyzed by GC-MS, periodate oxidation, Smith degradation, FT-IR, methylation and NMR, which indicated that the AGP was composed of → 6)-ß-d-Glcp-( â†’ backbone and the â†’4)-α-d-Xylp-(1→, →5)-α-l-Araf-(1→, →3)-α-l-Rhap-(1→, →6)-α-d-Galp-(1→, →3,6)-α-Manp-(1→ and →1)-ß-d-Glcp as branches. The results of Congo red experiment and circular dichroism (CD) showed that there was triple helix conformation in AGP. The micro-structure of AGP were detected by scanning electron microscopy (SEM), which concluded that the shape of AGP was a "thin slice" and its structure is not regular. The crystal configuration was identified by X-ray diffraction (XRD), showing that there is no crystal structure. Furthermore, the AGP exhibited certain inhibition activity on α-glucosidase.

Structural characteristics of Medicago Sativa L. Polysaccharides and Se-modified polysaccharides as well as their antioxidant and neuroprotective activities.

Medicago Sativa L., a nutrient-rich plant used as feed for cattle and sheep, is widely planted globally. This study investigated the structural characteristics and activities of three kinds of novel polysaccharides (APS1, APS2 and APS3) isolated from the stems of M. sativa as well as its two selenium modified products (Se-APS2 and Se-APS3). APS1 (Mw = 13.4 KDa) and APS2 (Mw = 11.2 KDa) were composed of rhamnose, arabinose, mannose and galactose with different molar ratio, APS3 (Mw = 18.6 KDa) was composed of rhamnose, arabinose, fructose, mannose and galactose. All APS1-3 contained 1 â†’ 3 : 1 â†’ 6 : 1 â†’ 4 : 1 â†’ 2 glycosidic bonds in a ratio of 0.74:0.09:0.05:0.12, 0.34:0.20:0.36:0.10 and 0.63:0.17:0.06:0.14, respectively. The selenium content of Se-APS2 (Mw = 9.0 KDa) and Se-APS3 (Mw = 10.2 KDa) were 1.05 and 2.57 µg/mg, respectively. Their surface morphology and thermal stability were determined by scanning electron microscope (SEM) and thermal analysis (TGA), respectively. Further, the antioxidant and neuroprotective activities of the three natural polysaccharides and two Se-polysaccharides were studied. Interestingly, Se-polysaccharides not only exhibited higher antioxidant activity, but also higher neuroprotective activity compared to natural polysaccharides.

Tyramine-modified pectins via periodate oxidation for soybean hull peroxidase induced hydrogel formation and immobilization.

Pectin was modified by oxidation with sodium periodate at molar ratios of 2.5, 5, 10, 15 and 20 mol% and reductive amination with tyramine and sodium cyanoborohydride afterwards. Concentration of tyramine groups within modified pectin ranged from 54.5 to 538 µmol/g of dry pectin while concentration of ionizable groups ranged from 3.0 to 4.0 mmol/g of dry polymer compared to 1.5 mmol/g before modification due to the introduction of amino group. All tyramine-pectins showed exceptional gelling properties and could form hydrogel both by cross-linking of carboxyl groups with calcium or by cross-linking phenol groups with peroxidase in the presence of hydrogen peroxide. These hydrogels were tested as carriers for soybean hull peroxidase (SHP) immobilization within microbeads formed in an emulsion based enzymatic polymerization reaction. SHP immobilized within tyramine-pectin microbeads had an increased thermal and organic solvent stability compared to the soluble enzyme. Immobilized SHP was more active in acidic pH region and had slightly decreased K m value of 2.61 mM compared to the soluble enzyme. After 7 cycles of repeated use in batch reactor for pyrogallol oxidation microbeads, immobilized SHP retained half of the initial activity.

Characterization of Periodic Acid-Schiff-Positive Granular Deposits in the Hippocampus of SJL/J Mice.

Periodic acid-Schiff (PAS)-positive granular deposits in the hippocampus have been reported previously in certain inbred mouse strains such as C57BL/6 and the senescent-accelerated mouse prone-8. Here, we report for the first time that similar PAS-positive granules age dependently occur in SJL/J mice, a mouse strain, for instance, used for central nervous system disease research. Moreover, similar granules stained intensely positive with a polyclonal antibody directed against p75 neurotrophin receptor (p75(NTR)). Granular deposits were absent in young mice and developed with aging in CA1 and CA2 regions of the hippocampus. Interestingly, granules significantly diminished in SJL/J mice previously treated with cuprizone, a copper chelator, which is a useful model for toxic demyelination. The presented data support the idea that granules might be the result of an imbalance of redox-active metals and/or a dysregulation of complementary mechanisms that regulate their homeostasis in astrocyte-neuron coupling, respectively. It remains to be determined whether the unsuspected immunoreactivity for p75(NTR) represents a false-positive reaction or whether p75(NTR) is crucially involved in the pathogenesis of age-related hippocampal granular deposits in mice.

Preparation and characterization of in-situ crosslinked pectin-gelatin hydrogels.

Crosslinked hydrogels were developed by in-situ reaction of periodate oxidized pectin (OP) and gelatin. The reaction takes place through the formation of Schiff bases between aldehyde groups of OP and amino groups of gelatin. The effect of various process parameters such as reaction time, reaction temperature, pH of the reaction and composition on the efficacy of the crosslinking was investigated. Field emission scanning electron micrsocopy (FESEM) revealed that homogenous, single phase systems are obtained after the crosslinking of OP and gelatin. The swelling characteristics of the hydrogels were monitored. The equilibrium swelling varies in the range of 195-324% with a variation in the gelatin content (10-40%). Glycerol, when used as a plasticizer, improved the flexibility and the handling characteristics of the crosslinked hydrogels. Plasticized films retained good tensile strengths in the range of 19-48 MPa. By proper selection of the reaction conditions, the efficiency of crosslinking can be controlled to obtain the optimum results.

Functionalization of pectin by periodate oxidation.

High methoxy citrus pectin was oxidized by periodic acid to prepare a dialdehyde functionalized material. The effect of various reaction conditions, viz., reaction time, reaction temperature, pH of the medium, periodic acid concentration and solvent composition on the oxidation process was investigated. With an increase in the reaction time, the aldehyde content increased. However, the intrinsic viscosity of the system decreased indicating that degradation takes place simultaneously with oxidation. The amount of aldehyde generated also increased with an increase in reaction temperature and the concentration of periodic acid. Due to the polyanionic behaviour of pectin, greater aldehyde contents were obtained at lower pH. Keeping all other reaction conditions constant, greater aldehyde contents were obtained in water-ethanol system than in pure aqueous medium. Increase in the ethanol content increased the amount of aldehyde generated. FTIR spectra of oxidized pectin systems show a carbonyl peak at 1734 cm(-1). They further reveal that partial ionisation of-COOH groups takes place leading to a peak at 1614 cm(-1).

A novel approach of periodate oxidation coupled with HPLC-FLD for the quantitative determination of 3-chloro-1,2-propanediol in water and vegetable oil.

A novel approach of periodate oxidation coupled with high-performance liquid chromatography (HPLC)-fluorescence detection (FLD) for the quantitative determination of 3-chloro-1,2-propanediol (3-MCPD) has been established. The essence of this approach lies in the production of chloroacetaldehyde by the oxidization cleavage of 3-MCPD with sodium periodate and the HPLC analysis of chloroacetaldehyde monitored by an FLD detector after fluorescence derivatization with adenine. The experimental parameters relating to the efficiency of the derivative reaction such as concentration of adenine, chloroacetaldehyde reaction temperature, and time were studied. Under the optimized conditions, the proposed method can provide high sensitivity, good linearity (r(2) = 0.999), and repeatability (percent relative standard deviations between 2.57% and 3.44%), the limits of detection and quantification were 0.36 and 1.20 ng/mL, respectively, and the recoveries obtained for water samples were in the range 93.39-97.39%. This method has been successfully applied to the analysis of real water samples. Also this method has been successfully used for the analysis of vegetable oil samples after pretreatment with liquid-liquid extraction; the recoveries obtained by a spiking experiment with soybean oil ranged from 96.27% to 102.42%. In comparison with gas chromatography or gas chromatography-mass spectrometry, the proposed method can provide the advantages of simple instrumental requirement, easy operation, low cost, and high efficiency, thus making this approach another good choice for the sensitive determination of 3-MCPD.

[Synthesis and identification of rutin complete antigen and analysis its immunogenicity].

OBJECTIVE: Synthesis and identification of complete antigen of rutin, the traditional Chinese medicine active ingredient, and develop rapid detection of rutin using enzyme-linked immunoassay method (ELISA). Immunogenicity of the complete antigen was also studied. METHOD: Prepare the complete antigen by sodium periodate solution and identified by UV scanning and SDS-PAGE test. Male New Zealand white rabbits were immunized by the antigen to obtain the antiserum. RESULT: The results of UV analysis showed that the coupling ratio of complete antigen is 13: 1. SDS-PAGE display of the artificial antigen was delayed compared with bovine serum protein. The titer of rutin antibody is 1:4 000. The sensitivity of IC50 was 5.37 mg x L(-1), the lowest detection limit was 1 mg x L(-1), the average recovery was 102%, the intra and interspecific RSD were less than 10%, cross-reactivity rate of antibodies and other analogs were less than 1%. CONCLUSION: Rutin complete antigen was synthesized successfully, and the rapid detection of rutin by ELISA method was successfully established.

Immunomodulating pectic polysaccharides from waste rose petals of Rosa damascena Mill.

A water-soluble polysaccharide (RP-1) was obtained from distilled rose petals of Rosa damascena Mill. as an attempt for valorization of the waste. RP-1 showed in vitro intestinal immune system modulating activity through Peyer's patch cells and IL-6 producing activity from macrophages. RP-1 lost most of its immunomodulating activity by degradation of the carbohydrate moiety with periodate. RP-1 was fractionated by anion-exchange and gel filtration chromatography and some of the fractions showed significant intestinal immune system modulating activity. The active fractions were suggested to be pectic polysaccharides and type II arabino-3,6-galactan from the component sugar analyses and the reactivity with Yariv antigen. When some active fractions were digested with endo α-d-(1→4)-polygalacturonase, highest molecular weight fragments which were considered as rhamnogalacturonan I, showed potent immunomodulating activities. To our knowledge, this is a first report which explores the possibility for utilization of waste rose petals as a source of immunomodulating pectic polysaccharides.

Further analysis of the structure and immunological activity of an RG-I type pectin from Panax ginseng.

In this paper, we further analysed the structure of a type I rhamnogalacturonan (RG-I) pectin (WGPA-2-RG) fractionated from ginseng polysaccharides. Methylation and periodate oxidation analyses showed that WGPA-2-RG has a backbone consisting of alternating rhamnose (Rha) and galacturonic acid (GalA) residues and side chains consisting of type II arabinogalactan (AG-II). Partial acidic hydrolysis for 6h completely removed arabinose (Ara), partial galactose (Gal), but little GalA and Rha. During partial hydrolysis, the molecular weight of WGPA-2-RG decreased smoothly, suggesting that the Ara and cleavable Gal residues exist on the surface of the molecule, while GalA and Rha residues exist in the core of the molecule. The bioactivity assay showed that the arabinogalactan side chains of WGPA-2-RG are essential structures for stimulating NO secretion and lymphocyte proliferation. However, removal of the Ara and Gal residues through hydrolysis did not appreciably affect the ability of WGPA-2-RG to enhance macrophage phagocytosis.

Selective spectrophotometric determination of periodate based on its reaction with methylene green and its application to indirect determination of ethylene glycol and glycerol.

A rapid, simple, accurate, and highly selective spectrophotometric method is proposed for the determination of periodate in water samples. This method is based on the reaction of methylene green with periodate in the presence of iodide. The decrease in the absorbance of methylene green is used to monitor the reaction spectrophotometrically at 613 nm. Under the optimum conditions, periodate could be determined in the concentration range 0.18-6.0 microg mL(-1). The detection limit for the method is 0.010 microg mL(-1). The influence of various foreign species was studied, and it was found that iodate did not interfere with the determination even in the presence of 200-fold of periodate. The relative standard deviations for six replicate determinations of 0.30, 0.50, 1.0, 1.5, 4.0, and 5.5 microg mL(-1) of periodate were 3.33, 2.0, 1.6, 1.33, 0.50, and 0.55%, respectively. The proposed method was applied to the determination of periodate in water samples and indirect determination of ethylene glycol in antifreeze and glycerol in vegetable oil via malaprade reaction, and satisfactory results were obtained.

Rapid quantification of total microcystins in cyanobacterial samples by periodate-permanganate oxidation and reversed-phase liquid chromatography.

Microcystins (MCs) comprise a family of more than 80 related cyclic hepatotoxic heptapeptides. Oxidation of MCs causes cleavage of the chemically unique C20 beta-amino acid (2S, 3S, 8S, 9S)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda) amino to form 2-methyl-3-methoxy-4-phenylbutanoic acid (MMPB), which has been exploited to enable analysis of the entire family. In the present study, the reaction conditions (e.g. concentration of the reactants, temperature and pH) used in the production of MMPB by oxidation of cyanobacterial samples with permanganate-periodate were optimized through a series of well-controlled batch experiments. The oxidation product (MMPB) was then directly analyzed by high-performance liquid chromatography with diode array detection. The results of this study provided insight into the influence of reaction conditions on the yield of MMPB. Specifically, the optimal conditions, including a high dose of permanganate (> or = 50 mM) in saturated periodate solution at ambient temperature under alkaline conditions (pH approximately 9) over 1-4 h were proposed, as indicated by a MMPB yield of greater than 85%. The technique developed here was applied to determine the total concentration of MCs in cyanobacterial bloom samples, and indicated that the MMPB technique was a highly sensitive and accurate method of quantifying total MCs. Additionally, these results will aid in development of a highly effective analytical method for detection of MMPB as an oxidation product for evaluation of total MCs in a wide range of environmental sample matrices, including natural waters, soils (sediments) and animal tissues.

Class I major histocompatibility complexes loaded by a periodate trigger.

Class I major histocompatibility complexes (MHCs) present peptide ligands on the cell surface for recognition by appropriate cytotoxic T cells. The unstable nature of unliganded MHC necessitates the production of recombinant class I complexes through in vitro refolding reactions in the presence of an added excess of peptides. This strategy is not amenable to high-throughput production of vast collections of class I complexes. To address this issue, we recently designed photocaged MHC ligands that can be cleaved by a UV light trigger in the MHC bound state under conditions that do not affect the integrity of the MHC structure. The results obtained with photocaged MHC ligands demonstrate that conditional MHC ligands can form a generally applicable concept for the creation of defined peptide-MHCs. However, the use of UV exposure to mediate ligand exchange is unsuited for a number of applications, due to the lack of UV penetration through cell culture systems and due to the transfer of heat upon UV irradiation, which can induce evaporation. To overcome these limitations, here, we provide proof-of-concept for the generation of defined peptide-MHCs by chemical trigger-induced ligand exchange. The crystal structure of the MHC with the novel chemosensitive ligand showcases that the ligand occupies the expected binding site, in a conformation where the hydroxyl groups should be reactive to periodate. We proceed to validate this technology by producing peptide-MHCs that can be used for T cell detection. The methodology that we describe here should allow loading of MHCs with defined peptides in cell culture devices, thereby permitting antigen-specific T cell expansion and purification for cell therapy. In addition, this technology will be useful to develop miniaturized assay systems for performing high-throughput screens for natural and unnatural MHC ligands.

Polysaccharide templated silver nanowire for ultrasensitive electrical detection of nucleic acids.

An ultrasensitive electrical detection method of nucleic acids has been developed on a nanogapped biosensor. In this study, peptide nucleic acid (PNA) probes were immobilized in the gaps of a pair of finger microelectrodes first and were then hybridized with their complementary target DNA. After that, pectin molecules were introduced into the DNA strand via zirconium-phosphate and zirconium-carbonate chemistries and were oxidated by periodate in acetate buffer (pH 3.98). The newly produced aldedyde groups act as a reactant to reduce ammoniacal silver ion to produce silver nanoparticles, which bridged the gap of the interdigitated microelectrode. The conductance of the metallic nanoparticles correlated directly with the amount of the hybridized DNA. A much higher sensitivity was achieved at 3 femtomolar (S/N > 3) under optimal conditions. This biosensor is also applicable to the direct detection of RNA.

Kinetic spectrophotometric determination of rutin by its inhibitory effect on the oxidation of amaranth by potassium periodate.

A novel kinetic spectrophotometric method is described for the determination of rutin. The method is based on the inhibitory effect of rutin on the oxidation reaction of amaranth by potassium periodate in acidic media at 100 degrees C. The linear range for the determination of rutin is 0.02 - 0.50 microg/ml, and the detection limit is 0.014 microg/ml. The method has been successfully applied to the determination of rutin in medicine of rutin tablet and traditional Chinese medicine.

Chemical constituents from Cimicifuga foetida.

From the rhizoma of Cimicifuga foetida L. (Ranunculaceae) a new chromone, 6'-hydroxylangelicain (18), has been isolated together with 20 known compounds. The structure of 18 has been elucidated on the basis of spectroscopic and chemical evidence.

A potential antiviral flavone glycoside from the seeds of Butea monosperma O. Kuntze.

A potential antiviral flavone glycoside has been isolated from the seeds of Butea monosperma O. Kuntze and its structure determined as 5,2'-dihydroxy-3,6,7-trimethoxyflavone-5-O-beta-D-xylopyranosyl-(1-->4)-O-beta-D-glucopyranoside (1) by various spectral analysis and chemical degradations.

Optical sensor for the determination of glucose based on KIO4 chemiluminescence detection.

A method to determine glucose using an optical sensor prepared by entrapping glucose oxidase into silica sol-gel column has been developed. The silica sol-gel film was coated on alumina substrate. The optical sensor is based on the chemiluminescence intensity from the reaction of periodate and hydrogen peroxide in K2CO3 medium. The effect of the ratio of water and alcohol for the preparation of TEOS sol on chemiluminescence intensity was investigated. The effects of pH of enzyme reactor, concentrations of potassium periodate and SDS, and flow rate on the chemiluminescence intensity were studied to find the optimum experimental conditions to determine glucose. The chemiluminescence intensity increased linearly with increasing glucose concentration from 5.0 x 10(-4) M to 1.0 x 10(-7) M and the detection limit was 4.0 x 10(-8) M. Interference effects from some metal ions on chemiluminescence intensity were also investigated.

Primary structure and configuration of tea polysaccharide.

The monosaccharide composition of a tea polysaccharide (TGC) was determined by GC-MS method. Furthermore, the primary structure of tea polysaccharide and its configuration in the aqueous solution were investigated utilizing a combination of classical chemical methods and modern instrumental techniques including GC-MS, Proton NMR, UV and CD. The results indicate that TGC consists of 6 monosaccharides: Rha, Ara, Xyl, Glu, Man and Gal. The configuration of TGC in water solution is proposed to be an ordered helix. The possible primary structure of TGC was outlined as below: the basic structure of the main chain consists of Rha, Glu and Gal units. All three monosaccharides can potentially be connected to branch chains consisting of mainly Ara, and the linkages could be in beta1 --> 2, beta1 --> 3, beta2 --> 3 forms. When branch chain is absent in the basic structure of the main chain the linkage consists of only beta1 --> 3; Xyl exists at the terminal end of either the main chain or the branch chain with beta1 --> linkage.