Curculigo orchioides polysaccharides extraction,characterization, and their protective effects against femoral head necrosis

The use of steroid drugs such as dexamethasone in long-term treatment poses a challenge called femoral head necrosis. To reduce the destructive effects of dexamethasone, the use of herbal suppressants such as Curculigo orchioides polysaccharides (COPs) is recommended despite the ambiguities in their chemical composition and the effects of each component on the anti-necrosis activity of the femoral head. In this study, after separation of COPs through hot water–ethanol precipitation method and purification through DEAE-Sepharose fast flow column, their properties were explained by FTIR, NMR, methylation and chromatography. Moreover, the COPs biocompatibility and its inhibitory effects against dexamethasone-induced cytotoxicity were evaluated by MTT assay and gene expression on human primary osteoblasts cells. The results exhibit that the 4756 Da molecular weight COPs is generally composed of Rha, Ara, Fru, Xyl, Man, Glc, Gal, Glu A and Gal A. Also, MTT results recognized high biocompatibility of COPs and suppressive effect on dexamethasone. Also, COPs significantly reduced dexamethasone-induced intracellular levels of apoptosis and ROS. Furthermore, the use of COPs has significantly increased ALP activity, collagen content and mineralization, which are very effective in differentiating HPOS cells to repair bone tissue. Meanwhile, the gene expression outcomes indicate an increase in Bcl-2 expression gene and decrease in BAX, Caspase-9 and Caspase-3 gene expression in the presence of COPs, which are important in controlling apoptotic activity and bone regeneration. Overall, this study revealed that COPs can lead to the treatment of femoral head necrosis.     

Enantiomer separation and indirect chromatographic absolute configuration prediction of chiral pirinixic acid derivatives: Limitations of polysaccharide-type chiral stationary phases in comparison to chiral anion-exchangers

Chiral α-arylthiocarboxylic acids with different substitution patterns, representing new pirinixic acid derivatives with dual PPARα/γ agonistic activities, have been separated into enantiomers on tert-butylcarbamoylquinine and quinidine based chiral anion-exchangers and amylose tris(3,5-dimethylphenylcarbamate) coated silica on analytical and preparative scale. Absolute configurations of individual enantiomers were assigned chromatographically via elution orders on the chiral anion-exchangers and were confirmed by stereoselective syntheses via Ewans auxiliaries that have lead to enantiomeric products with known absolute configurations. The results of both methods were in full agreement. Moreover, the receptor stereoselectivity in PPARα transactivation activities was consistent within the test set of structurally related compounds. Limited correlation (between elution order and substitution) was observed within the set of α-arylthiocarboxylic acids on the amylose tris(3,5-dimethylphenylcarbamate) based chiral stationary phase (CSP), in particular the elution order changed with remote substitution. This clearly demonstrates the risks of chromatographic absolute configuration assignments by prediction from one structural analog to another one, especially with CSPs such as polysaccharide CSPs that are recognized for their broad applicability due to multiple binding and chiral recognition modes. It is therefore of utmost importance that such chromatographic absolute configuration predictions by extrapolation to structural analogs are combined with orthogonal methods for verification of the results.     

Voltammetry of Os(VI)‐Modified Polysaccharides

Polysaccharides (PSs), such as dextran, yeast mannan, starch and amylose, were modified with complexes of six‐valent osmium with nitrogen ligands [Os(VI)L] and voltammetric behavior of PS‐Os(VI)L adducts was studied at mercury and carbon electrodes. Using Os(VI)temed as a modification agent and adsorptive transfer stripping (ex situ) method it was possible to determine PSs at submicromolar concentrations directly in the reaction mixture in an excess of monomeric glucose or sucrose both at Hg and carbon electrodes. Conventional (in situ) PS determination in the reaction mixture was possible only with mercury electrodes. The above methods have great potentiality in biological research.     

Optimization of the LC enantioseparation of chiral pharmaceuticals using cellulose tris(4‐chloro‐3‐methylphenylcarbamate) as chiral selector and polar non‐aqueous mobile phases

The resolving power of a new commercial polysaccharide‐based chiral stationary phase, Sepapak‐4, with cellulose tris(4‐chloro‐3‐methylphenylcarbamate) coated on silica microparticles as chiral selector, was evaluated toward the enantioseparation of ten basic drugs with widely different structures and hydrophobic properties, using ACN as the main component of the mobile phase. A multivariate approach (experimental design) was used to screen the factors (temperature, n‐hexane content, acidic and basic additives) likely to influence enantioresolution. Then, the optimization was performed using a face‐centered central composite design. Complete enantioseparation could be obtained for almost all tested chiral compounds, demonstrating the high chiral discrimination ability of this chiral stationary phase using polar organic mobile phases made up of ACN and containing an acidic additive (TFA or formic acid), 0.1% diethylamine and n‐hexane. These results clearly illustrate the key role of the nature of the acidic additive in the mobile phase.     

Cell wall polysaccharides in cereals: chemical structures and functional properties

β-Glucans and arabinoxylans are the two primary cell wall structural components in cereals, such as wheat, oat, barley and rye. The relative amounts of the two polysaccharides vary with species and growing environments. The cell walls of barley and oats are generally rich in β-glucan, whereas rye and wheat cell walls contain higher levels of arabinoxylans. Cereal β-glucan is a mix linked (1 → 3) (1 → 4)-β-d-glucan composed of two major building blocks: a trisaccharide and a tetrasaccharide unit: the combination of the two units is over 90%. The ratio of the two building blocks is used as a fingerprint for each β-glucans: it is 4.5, 3.3, 2.2 for wheat, barley and oat β-glucan, respectively. Of the two types of cell wall polysaccharides in cereals, β-glucan received greater attention due to its proved beneficial physiological effect as an excellent source of soluble dietary fibre for significantly attenuating blood glucose and insulin levels and its demonstrated ability to reduce low-density lipoprotein cholesterols (LDL) in serum. The ability of cereal β-glucan to attenuating blood glucose, insulin levels is linked to the viscosity produced by cereal β-glucans in a linear relationship. It is also demonstrated that the functional properties of cereal β-glucans are determined by their structural features and molecular weight: a higher trisaccharide to tetrasaccharide ratio favours gel formation and faster gelation process, and ultimately, gives stronger gels. Cereal β-glucan also demonstrated an unusual behaviour by forming gel faster and yielding stronger gels at lower molecular weight (above minimum gelation molecular weight). Such a structure–function relationship was established based on rheological, light scattering and computer modelling studies which cover both dilute and concentrated concentration regimes: high tri/tetra ratio gives high proportion of consecutive trisaccharide unit which favours the intermolecular association of β-glucan chains; on the other hand, low molecular weight chains have higher mobility that promotes intermolecular chain–chain interactions, hence, lead to faster gelation process and formation of stronger gels. Research also revealed that processing and storage conditions, such as temperature, pH, extrusion, baking and frozen before eating, have significant effects on the bioavailability of cereal β-glucans, hence, its ability to reduce blood glucose and cholesterol levels.     

HPLC with polysaccharide chiral stationary phase in polar‐organic phase mode: Application to the asymmetric epoxidation of allylic alcohols

A simple and rapid HPLC method using a polysaccharide‐based chiral stationary phase (Chiralpak AD‐H) in polar‐organic phase mode has been developed for direct resolution of glycidyl nitrobenzoate (GNB) and 2‐methyl glycidyl nitrobenzoate (MGNB) enantiomers. ACN and methanol were used as mobile phase and the effects of the addition of ethanol and 2‐propanol as organic modifier in the mobile phase, flow rate and the column temperature were tested. The optimized conditions were: methanol/ethanol (80:20) at a flow rate of 0.9 mL/min and 40°C. Analysis time was ?13 min and the chiral resolution was ?2. The method was validated and resulted to be selective, precise and accurate. The method was found to be linear in 2–300 μg/mL range (R² >0.999) with an LOD nearly 0.5 μg/mL for four enantiomers. GNB and MGNB enantiomers were obtained by asymmetric epoxidation of allyl alcohol and 2‐methyl allyl alcohol, respectively, using chiral titanium–tartrate complexes as catalyst and dichloromethane as solvent after in situ derivatization of the intermediate glycidols derivatives. The quite simple and rapid validated method was applied successfully for direct determination of the enantiomeric excess (?90%) and yield obtained in real samples of asymmetric epoxidation of allylic alcohols without further purification, workup or solvent removal. The method provides a useful and value‐added tool for controlling the enantiomeric purity of the synthesized epoxides.     

Total Fractionation and Analysis of Polysaccharides from Leaves of Panax ginseng C. A. Meyer

The water-soluble polysaccharides isolated from the leaves of Panax ginseng C.A.Meyer were totally fractionated into one neutral fraction(GLPN-1),six acidic fractions(GLPN-2,GLPA-1a,GLPA-1b,GLPA-1c,GLPA-2 and GLPA-3) by a combination of ethanol precipitation,ion-exchange and gel permeation chromatography.All the fractions were analyzed by determining monosaccharide composition,molecular weight distribution.The results show that GLPN-1 was mainly composed of Gal(38.1%) and Ara(33.6%) and presumed to be an ar...     

Fouling of reverse osmosis membranes by biopolymers in wastewater secondary effluent: Role of membrane surface properties and initial permeate flux

Reverse osmosis (RO) is being increasingly used in treatment of domestic wastewater secondary effluent for potable and non-potable reuse. Among other solutes, dissolved biopolymers, i.e., proteins and polysaccharides, can lead to severe fouling of RO membranes. In this study, the roles of RO membrane surface properties in membrane fouling by two model biopolymers, bovine serum albumin (BSA) and sodium alginate, were investigated. Three commercial RO membranes with different surface properties were tested in a laboratory-scale cross-flow RO system. Membrane surface properties considered include surface roughness, zeta potential, and hydrophobicity. Experimental results revealed that membrane surface roughness had the greatest effect on fouling by the biopolymers tested. Accordingly, modified membranes with smoother surfaces showed significantly lower fouling rates. When Ca²⁺ was present, alginate fouled RO membranes much faster than BSA. Considerable synergistic effect was observed when both BSA and alginate were present. The larger foulant particle sizes measured in the co-existence of BSA and alginate indicate formation of BSA-alginate aggregates, which resulted in greater fouling rates. Faster initial flux decline was observed at higher initial permeate flux even when the flux was measured against accumulative permeate volume, indicating a negative impact of higher operating pressure.     

马蹄金多糖提取及含量测定

比较不同温度条件下超声水提-醇沉和加热回流水提-醇沉提取马蹄金多糖的效率,再分别用Sevag法去蛋白制得粗多糖,从而确定一种马蹄金多糖提取的最适方法.多糖经苯酚-硫酸显色后在490nm处用紫外-可见分光光度计进行比色测定.结果表明,超声条件下,温度与提取效率成正比,但超声提取与煮沸下加热回流提取比较,加热回流的提取方法效率较高.这为进一步提取、分析马蹄金多糖及其药理学研究提供理论依据.     

香菇多糖L-2A的结构表征

从香菇子实体中提取纯化得到香菇多糖级分L-2A,利用紫外光谱、红外光谱、凝胶渗透色谱和气相色谱分析其结构特征.香菇多糖L-2A糖含量为90.14%;重均分子量是2.03×10 5道尔顿;具有D-葡萄吡喃糖构型,单糖组成主要是由吡喃型葡萄糖组成;香菇多糖L-2A多糖含有o-糖苷键,且主要是o-Ser连接方式;具有与刚果红结合的螺旋结构.香菇多糖L-2A为首次从香菇子实体中分离得到.