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Two chiral coordination clusters {CuII48Na12}, which can only be revealed by synchrotron single-crystal X-ray diffraction, were assembled unexpectedly from a system resembling the long-studied Fehling's solution. As the intricate structures themselves indicate, the ingenuity of using multiple ligands should inspire new strategies to fabricate new compounds. [ABSTRACT FROM AUTHOR]

Syzygium jambos is an Indo-Malaian found in many tropical countries and it is mainly composed of carbohydrates. Fraction PF-WSP and SF-WSP were obtained by aqueous extraction followed by Fehling’s treatment. Monosaccharide analysis showed that fraction PF-WSP has a high content of uronic acids (90%) and fraction SF-WSP presented mainly galactose (39.1%) and arabinose (34.2%), as neutral sugars and 9% of galacturonic acid. The presence of type II arabinogalactan in SF-WSP was evidenced by methylation analysis and 13 C/ 1 H HSQC NMR experiments. Immunomodulating properties of SF-WSP was investigated. It decreases THP-1 macrophage viability at the highest concentration tested (200 μg/mL). We then tested non-cytotoxic concentrations of SF-WSP on THP-1 cytokine production in the presence and absence of LPS. The results showed that SF-WSP increased TNF-α, IL-1β and IL-10 secretion in a concentration-dependent manner as well as attenuated the inflammatory response induced by LPS at the highest concentration (100 μg/mL). These results contribute to elucidate the effects of fruit pectic polysaccharides on immune cells. [ABSTRACT FROM AUTHOR]

The development of copper catalyzed azide–alkyne cycloaddition in aqueous solvent system at room temperature is a notable contribution to the field of green chemistry. In this work, 1,4-disubstitued- 1H -1,2,3-triazoles are synthesized in the Fehling solution, a widely used system in practical laboratory classes but totally unexplored in research field, with N , N -diisopropylethylamine/hydrazine without using any organic solvent under mild reaction conditions. [ABSTRACT FROM AUTHOR]

The first example of homogeneous copper-catalyzed aerobic oxidation of aldehydes is reported. This method utilizes atmospheric oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification. [ABSTRACT FROM AUTHOR]

A species model for the copper(II)/ L-(+)-tartaric acid (LH2, tartH2) aqueous system between pH 1.9 and 12.3 has been established by potentiometric, UV/Vis spectroscopic, solubility and crystallographic studies. Eight species were detected, including the oligonuclear major species Cu8L6H-10 in the neutral region and the mononuclear major species CuL2H-4 in the alkaline region, the latter being associated with Fehling's solution. The octanuclear complex was isolated as its lithium salt Li7[Cu8( L-tartH-2)4( L-tartH-1)2(H2O)6]NO3 ·19H2O ( 1). The 'Fehling species' CuL2H-4 was crystallized as its sodium, potassium and caesium salts, namely K2Na4[Cu( L-tartH-2)2] ·12H2O ( 2), Na6[Cu( L-tartH-2)2] ·9H2O ( 3), Na6[Cu( L-tartH-2)2] ·14H2O ( 4), and Cs6[Cu( L-tartH-2)2] ·8H2O ( 5). Each of them shows a distorted square-planar environment of copper(II), similar to the related non-chiral cuprate [Cu( rac-tartH-2-κ2 O2, O3)2]6- (S. Albrecht, P. Klüfers, Z. Anorg. Allg. Chem. 2013, 639, 280-284). By comparing the components of the UV/Vis spectra of Fehling's solution and the solids, we confirmed the identity of the major solution species. [ABSTRACT FROM AUTHOR]

Starfruit ( Averrhoa carambola L.) is an edible tropical fruit, which is usually consumed as a fresh table fruit or as fruit juice. It also exhibits various pharmacological activities. In this study, polysaccharides were extracted with boiling water and purified by freeze–thawing and Fehling treatments. After purification steps, a homogenous fraction was obtained. It was analyzed by sugar composition, gel permeation chromatography, methylation, and two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy analyses. It comprised arabinose (Ara), galactose (Gal), and galacturonic acid (GalA) in a molar ratio of 12.3:1.7:86.0. Methylation and NMR spectroscopy analyses showed that it contained a substituted galacturonan composed of (1→4)-linked α- d -Gal p A units branched at O -2 by (1→5)-linked α-l-Ara f and terminal α-l-Ara f and α- d -Gal p A units. The effect of PFSCW (10–300 mg/kg, i.p.) on nocifensive behavior induced by intraplantar injection of formalin in mice was evaluated. The fraction demonstrated antinociceptive and anti-inflammatory properties, suggesting that it may be useful in therapeutic intervention for the management of inflammatory pain. [ABSTRACT FROM AUTHOR]

A study of copper-mediated C-heteroatom especially C-N and C-O bond formations using simpler methodologies has been carried out. In the present work, acetylation of various substrates such as amines, phenols and alcohols; synthesis of 2,4,5-trisubstituted imidazole is done using simple and easily available starting materials. Copper (I) oxide was synthesized in situ by the reduction of Fehling's solution with glucose followed by its anchoring onto different supports like silica, HAP, basic alumina and cellulose. Comparison and contrasts between the reactivity of copper (I) oxide supported onto different supports for these reactions are made. The reactivity of copper (I) oxide seems to be largely dependent on the nature of support and the most active catalyst for a particular reaction was further characterized by different spectroscopic techniques such as FTIR, XRD, TGA, XPS, SEM, TEM and AAS. The catalysts were found to be stable, easily recyclable without any significant loss in activity. Graphical abstract: Applications of solid supported copper (I) oxides (where solid support is silica, HAP, cellulose and basic alumina) are studied for various organic transformations with special emphasis on C-N and C-O bond formation reactions.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] Conjugation of durian seed gum (DSG) with whey protein (WPI) promoted its emulsifying activity. [•] Covalent linkage of WPI to DSG facilitated its adsorption into the water/oil interface. [•] WPI–DSG conjugate exhibited better functional properties than DSG alone. [•] Fehling solution induced better functional properties than saturated barium hydroxide for DSG. [Copyright &y& Elsevier]

exhibited catalytic effect on the cracking reaction of double-stranded DNA (dsDNA) to form a short single-stranded DNA (ssDNA) that protected the nanogold (NG) to produce stable NGssDNA conjugate. The un-protected NG was aggregated to form NG aggregates (NGA) that appeared a resonance scattering (RS) peak at 542 nm. Unlike NGA, the NGssDNA exhibited a strong catalytic activity on the Cu2O particle reaction of Fehling reagent-glucose that can be monitored by RS technique at 608 nm. When theconcentration increased, the NGssDNA increased, and the RS intensity at 608 nm increased. The increased RS intensity ΔI608 nmwas linear to theconcentration in the range of 15–200 pmol L−1, with a regression equation of ΔI608 nm = 1.24 C + 4.6, and a detection limit of 5 pmol L−1. This new RS assay was applied to assayin water sample, with satisfactory results. [ABSTRACT FROM AUTHOR]

Fehling's solution is an aqueous alkaline solution (pH ca. 13) of D-, L-, or rac-tartrato-cuprates(II) and both excess tartrate and hydroxide. The isolation of crystalline solids succeeded for rac-tartrate-containing samples. Crystal structure analyses revealed the formulas K8[Cu10( rac-tartH-1)4( rac-tartH-2)4(H2O)4] ·18H2O ( 1), Li4[Cu2( rac-tartH-2-κ2 O1, O2:κ2 O3, O4)2] ·11.75H2O ( 2), and Na6[Cu( rac-tartH-2-κ2 O2, O3)2] ·14H2O ( 3). The cupric central atom is in a square-planar tetracoordination in the bis(diolato) chelate in 3, and in square-pyramidal 4+1 coordination in the mixed carboxylato-alkoxido chelates 1 and 2. In terms of stoichiometry, 3 is closest to typical Fehling recipes. [ABSTRACT FROM AUTHOR]

Natural biopolymers from plant sources contain many impurities (e.g., fat, protein, fiber, natural pigment and endogenous enzymes), therefore, an efficient purification process is recommended to minimize these impurities and consequently improve the functional properties of the biopolymer. The main objective of the present study was to investigate the effect of different purification techniques on the yield, protein content, solubility, water- and oil-holding capacity of a eteropolysaccharide-protein biopolymer obtained from durian seed. Four different purification methods using different chemicals and solvents (i.e., A (isopropanol and ethanol), B (isopropanol and acetone), C (saturated barium hydroxide), and D (Fehling solution)] to liberate the purified biopolymer from its crude form were compared. In most cases, the purification process significantly (p < 0.05) improved the physicochemical properties of heteropolysaccharide-protein biopolymer from durian fruit seed. The present work showed that the precipitation using isopropanol and acetone (Method B) resulted in the highest purification yield among all the tested purification techniques. The precipitation using saturated barium hydroxide (Method C) led to induce the highest solubility and relatively high capacity of water absorption. The current study reveals that the precipitation using Fehling solution (Method D) most efficiently eliminates the protein fraction, thus providing more pure biopolymer suitable for biological applications. [ABSTRACT FROM AUTHOR]

Ready-to-use indicatory forms shaped as tablets, e.g., glucotests, are proposed for the rapid semi-quantitative determination of glucose in foodstuffs. Their function is based on the classical Fehling's reaction with the selection of reagents aimed to eliminate the influence of proteins, reduce sample pretreatment to a minimum, and perform the test within 10 min. The glucotests are economical, simple to manufacture, and have no limits for shelf life and storage conditions. If necessary, the glucotests can be applied for the quantitative determination of glucose as well. To do this, a photometric procedure is proposed based on the quantification of unreacted copper acetate in the composition of the glucotest by its intrinsic absorbance. To analyze colorful products, sample pretreatment using an anion-exchange resin in the acetate form is recommended. [ABSTRACT FROM AUTHOR]

Gold nanoparticle particles in size of 10 nm were used to label the thiol-modified single-stranded DNA aptamer (SH-ssDNA) to obtain an aptamer-modified gold nanoparticle probe (AussDNA) for target DNA (tDNA). In pH 7.4 NaH2PO4–Na2HPO4 buffer solution, the hybridization reaction between AussDNA and tDNA took place to form larger aptamer-modified gold nanoparticle cluster complex. The excess aptamer-modified gold nanoparticle probe in the supernatant solutions was obtained by centrifuging and can be used as nanocatalyst for the 0.276 mmol/L CuSO4-65.4 mmol/L potassium-sodium tartrate-0.37 mmol/L glucose system at 70 °C. The cubic Cu2O particles generated by the nanocatalytic reducing exhibit a strong resonance scattering (RS) peak at 620 nm. In the selected conditions, the RS intensity at 620 nm decreased with addition of tDNA, and the decreased intensity Δ I620 nm is proportional to tDNA concentration ( CtDNA) from 0.12 to 72 pM, with regress equation of Δ I620 nm = 1.29 CtDNA + 4.05, correlation coefficient of 0.9917, and detection limit of 0.084 pM tDNA. [ABSTRACT FROM AUTHOR]

Abstract: Members of the genus Malassezia are commensal fungi found on the skin of both human and domestic animals and are associated with skin diseases including dandruff/seborrheic dermatitis, pityriasis versicolor, and atopic eczema (AE) in humans. In this study we have characterized the cell-wall carbohydrates of Malassezia sympodialis, one of the species most frequently isolated from both AE patients and healthy individuals. Cells were grown in liquid Dixon media at 32°C, harvested, and processed using a standard Fehling’s precipitation methodology for the isolation of mannan and a standard base/acid extraction for (1→3)-β-d-glucans. Using these classic extraction methods we were unable to isolate precipitable mannan or insoluble (1→3)-β-d-glucan. However, acidification and addition of methanol to the remaining Fehling’s-treated sample resulted in a very clean precipitate. This material was characterized by GPC–MALLS, 1D and 2D NMR, and GC–MS for monomer-type and linkage-type composition. We determined that trace amounts of both mannan and branched (1→3, 1→6)-β-d-glucan were present in the recovered precipitate, but not linear (1→3)-β-d-glucan. Surprisingly, NMR analysis indicated that (1→6)-β-d-glucan was the major carbohydrate component isolated from M. sympodialis cell wall. GC–MS linkage analysis confirmed the (1→6)-β-d-glucan structure. Based on these studies we have determined that the M. sympodialis cell wall contains (1→6)-β-d-glucan as the major carbohydrate component along with trace amounts of mannan and (1→3, 1→6)-β-d-glucan. In addition, these data indicate that modification of the classic mannan isolation methodology may be useful in the simultaneous isolation of both mannan and (1→6)-β-d-glucan from other fungi. [Copyright &y& Elsevier]

Two polysaccharides were isolated from submergedly cultured mycelium of the basidiomycete Ganoderma lucidum by extraction with alkali followed by fractionation with Fehling reagent. The polysaccharides were shown to be a linear (1→3)-α-D-glucan and a highly branched xylomannan containing a backbone built up of (1→3)-linked α-D-mannopyranose residues, the majority of which are substituted at O-4 by single β-D-xylopyranose residues or by disaccharide fragments β-D-Man p-(1→3)-β-D-Xyl p-(1→. Polysaccharide structures were elucidated by NMR spectroscopy in combination with methylation analysis and periodate oxidation. An interesting feature of the xylomannan is the simultaneous presence of α-D-mannopyranose and β-D-mannopyranose residues, the first forming the backbone, and the second being the non-reducing terminal units of disaccharide side chains. [ABSTRACT FROM AUTHOR]

Abstract: A novel and sensitive resonance scattering (RS) spectral immunoassay for the determination of microalbumin (Malb) was developed, based on the catalytic effect of immunonanogold (ING) probe on Fehling reagent–glucose reaction, and resonance scattering effect of Cu2O particles. Nanogold particles in size of 10nm were used to label goat anti-human microalbumin (GMalb) to obtain an ING probe (AuGMalb) for Malb. The probe produced unspecific aggregation in pH 5.0 citric acid–Na2HPO4 buffer solutions. Upon addition of Malb, the dispersed ING complex formed. The ING complex in supernatant was obtained by centrifuging and was used as catalyst for the reaction between Fehling reagent and glucose to form the Cu2O particles to amplify the resonance scattering signal at 610nm. With addition of Malb, the ING complex in the supernatant increased and the RS intensity at 610nm (I 610nm) enhanced linearly. The enhanced intensity ΔI 610nm was proportional to the Malb concentration in the range of 0.014–0.43ngml−1, with a detection limit of 7.2pgml−1. The proposed method was applied to detect Malb in human urine sample with satisfactory results. [Copyright &y& Elsevier]

Abstract: Nanogold exhibits strong catalytic effect on the slow reaction between glucose and Fehling reagent at 70°C. The production of Cu2O particles have two stronger resonance scattering (RS) peaks at 390nm and 505nm. The catalytic effect of nanogold-labeled goat anti-human IgG (AuIgG) on the reaction was investigated with the RS technique. Coupled the immunoreaction and the immunonanogold catalytic reaction and centrifugal technique, a highly sensitive and selective RS method was developed for the detection of immunoglobulin G (IgG) as a model. With the concentration of IgG increased, the RS intensity at 505nm decreased. The decreased intensity at 505nm ΔI 505 nm was proportional to IgG concentration in the range of 0.13–53.3ngmL−1, with a detection limit of 0.04ngmL−1 IgG. This new immunonanogold–catalytic Cu2O–particle RS bioassay was applied to the determination of IgG in serum sample, with high sensitivity, good selectivity, and low cost. [Copyright &y& Elsevier]

Lipopolysaccharide of Salmonella Agona smooth-type cells was obtained from bacteria by a hot phenol–water extraction procedure. Mild acid hydrolysis of lipopolysaccharide, followed by gel filtration, yielded the pure O-polysaccharide. Abequose, rhamnose, mannose, galactose and glucose in the molar ratio 0.8 : 1.0 : 1.0 : 1.1 : 0.5 were detected, and their linkages were established. Sugar configurations were determined by gas chromatography. Two repeating units, namely →2)-[α-Abe p-(1→3)-]-α-d-Man p-(1→4)-α-l-Rha p-(1→3)-α-d-Gal p-(1→and →2)-[α-Abe p-(1→3)-]-α-d-Man p-(1→4)-α-l-Rha p-(1→3)-[α-d-Glc p-(1→4)-]-α-d-Gal p-(1→, were deduced from nuclear magnetic resonance studies. The effort to separate them was unsuccessful. An immunochemical test performed by means of Western blotting with anti O12 serum demonstrated that glucose was present in the longer lipopolysaccharide chains, at some distance from the core region. [ABSTRACT FROM AUTHOR]

The Pizzolato test for calcium oxaIate crystals was applied to Dioscorea campestris. A blackening of intraamylar localization was obtained with this technique (silver nitrate and concentrated hydrogen peroxide). Nevertheless, the X-ray diffraction and crystal analysis were both negative for calcium oxalate and calcium respectively. The starch have single or semicompound granules, a great part of them have pores or holes in distal position with respect to the hilar region: sometimes there are 2 pores, with one of them in lateral position. The unmodified granules show the granule surface free from pores or cracks. The hole is supposed to be a conical crater erosion, a feature which is typical of the particular kind of starch granules highly resistant to liquefying α-amylase; the central portion is extensively affected as the erosion is in advance. The blackening produced by the positive Pizzolato test is related to that central portion of the damaged grains Microchemical tests with Fehling solution also revealed high concentrations of reducing sugars at these sites. It is possible that the silver reaction is due to the free reducing groups produced by hydrolysis of the internal central core, giving a false positive test for crystals. The X-ray diffraction powder diagrams obtained, yield data for a crystalline structure of amylose corresponding to the A-type starch. [ABSTRACT FROM AUTHOR]

Water-soluble polysaccharides, pectinic substances, and hemicelluloses were isolated from the aerial part of Ferula kuhistanica and F. tenuisecta. Their physicochemical properties were determined. [ABSTRACT FROM AUTHOR]

Nanosilver was modified by aptamer (ssDNA) to obtain a resonance scattering (RS) probe (AgssDNA) for melamine (MA). Based on the catalytic effect of the probe on the Fehling particle reaction, a nanocatalytic RS assay is proposed for the determination of 0.02–1.06 μg L−1MA. [ABSTRACT FROM AUTHOR]