Ultrasound-assisted extraction,analysis and antioxidant activity of polysaccharide from the rinds of Garcinia mangostana L.

According to response surface methodology (RSM), the extraction conditions of ultrasound-assisted extraction of polysaccharide from the rinds of Garcinia mangostana L. (GMRP) were optimized and determined. The optimal conditions obtained through optimization were: the liquid to material ratio was 40 mL/g, ultrasonic power was 288 W and extraction time was 65 min. The average extraction rate of GMRP was 14.73%. Ac - GMRP was obtained by acetylation of GMRP, and the antioxidant activities of the two polysaccharides were compared in vitro. The results indicated that the antioxidant capacity of polysaccharide obtained after acetylation was significantly improved compared with that of GMRP. In conclusion, chemical modification of polysaccharide is an effective measure to improve its properties to a certain extent. Meanwhile, it implies that GMRP has great research value and potential.     

紫外-可见分光光度法在植物多糖含量测定中的应用

紫外-可见分光光度法(UV-Vis)是目前国内比较常见的一种光谱学测量方法.且近年来,其在植物多糖含量测定领域的应用越来越多.本文从UV-Vis测定植物多糖含量过程中的显色剂选取、各种条件的优化以及具体应用等方面进行综述.     

Carrageenan as an elicitor of induced secondary metabolites and its effects on various growth characters of chickpea and maize plants

The effects of polysaccharide elicitor k-carrageenan obtained from Hypnea musciformis, red algae on the production of Induced Secondary Metabolites, ISMs (the disease resistance compounds) and on various growth characters of chickpea and maize plants were studied. Experiments were conducted in the field of PCSIR Laboratories Complex Karachi during December 2008–April 2009 in randomized complete block design with three replications. Three elicitor treatments were used, a solid preparation in which the elicitor was mixed with soil (T₂ 1 mg/g) and applied around the seeds in the soil. The two other preparations were liquid, T₁ and T₃ at a concentration of 100 μg glc eq ml⁻¹ and were applied around the sowing seeds and as a foliar spray on the plants, respectively. Statistical analysis of the data revealed that these treatments significantly enhanced all the growth characters of chickpea except T₂ that gave the nonsignificant difference in the plant height. Maximum plant height (80.3 cm), number of pods plant⁻¹ (76.2), number of branches plant⁻¹ (25.0), number of leaves plant⁻¹ (125.6), earlier flowering and high ISMs contents in leaves, stem and grains of chickpea were recorded in T₁ treated chickpea plants. In maize plants only T₁ and T₃ treatments (with minor exceptions) had significant effects on few characters like plant height, stem diameter, number of leaves plant⁻¹ and on ISMs contents in leaves while number of cobs plant⁻¹ and flowering time were nonsignificantly affected by these treatments. These results suggested that k-carrageenan elicitor can be used as a potent plant protectant as well as growth promoting agent especially for chickpea plants.     

Retention Behaviors of Uronic Acid-containing Polysaccharides and Neutral Polysaccharides in HPGPC

The determination of molecular weights (Mw) of polysaccharides has served as an important process since the physical properties of the polysaccharides are closely related to their Mw and/or molecular weights distribution (MWD). For Mw and MWD determinations, high performance gel permeation chromatography (HPGPC) has gained wide acceptance as a preferred method due to its high sensitivity, speed and reproducibility. In chromatography, it is well known that the molecular weights are determ…     

Effect of different chemical treatments on the pyrolysis products of Quercus petraea L. heartwood

Analytical pyrolysis was applied to oak wood to provide useful information concerning the structure of oak wood components and the effect of different treatments on the chemical structure of wood components. We have studied the influence of DMSO, H₂O₂, H₂O, acetic acid, and enzymatic treatments focusing on the qualitative and quantitative aspects. We studied the evolution of syringyl (S) and guaiacyl (G) compounds (main thermal degradation products of lignins) and the evolution of mallard reaction products, and main thermal degradation products of cellulose and hemicellulose.     

Participation of ions in promoting intermolecular associations of cell wall polysaccharides

The physiological functions of the two ions, Ca²⁺ and H⁺, in controlling mechanical properties of plant cell wall are reviewed. The interactions of these ions with major cell wall polysaccharides during cell growth and development are described. Experimental results for Ca²⁺/H⁺-induced molecular associations of some polysaccharides in solutions are also given. This article aims to bridge the understandings of molecular associations in solutions (in vitro) with those occurring in cell wall matrix of high order structure (in vivo).     

The significance of enterobacterial mutants for the chemical investigation of their cell-wall polysaccharides

The outer cell surface of Enterobacteriaceae, i.e. the cell wall, consist of a rigid structure (murein) on which additional proteins, lipids, and polysaccharides are deposited. In the bacterial wild types (S forms) the polysaccharide is species-specific and carries the serologically determinant groups of the respective O antigen. These specific polysaccharides often consist of a large number of monosaccharides; up to eight different monosaccharides may be involved. Bound to lipid A, the cell-wall lipopolysaccharides represent the endotoxins of the bacteria. During the past few years the structures of the enterobacterial cell-wall polysaccharides have been elucidated by chemical, immunochemical, biochemical, and genetic investigations, particularly in the Salmonella. Here the polysaccharides consists of a basal polysaccharide common to all species, to which (in the S form) are bound longer species-specific side chains, consisting of repeating oligosachharide units. Spontaneous S → R mutation leads to R forms which are deficient mutants of the wild types in regard to the biosynthesis of the complete cell-wall polysaccharide. In contrast to the multiplicity of the serological specificities of the somatic antigens of the S forms, only a few serological types were found among the R forms (R I, R II, etc.). These R polysaccharides correspond to intermediates in the biosynthesis of the wile-type polysaccharides. The S → R mutation leads to the loss (or block) of an enzymes (transferase, synthetase) participating in the synthesis of the S polysaccharides. Recently many deficient mutants have been isolated and analysed, and in this way numerous stages in the biosynthesis of the cell-wall polysaccharides, for example, of Salmonella minnesota, have been made accessible to direct analysis. According to these investigations, the cell-wall polysaccharides of Salmonella consist of a basic polyheptose phosphate core which is bound to lipid A via ketodeoxyoctonic acid. To the basic core are linked pentasaccharide units of (R II structure). All other R forms are structurally deficient mutants of R II. In the complete polysaccharides of Salmonella S forms (wild types), the repeating oligosaccharide units of the specific side, chain are bound to the terminal N-acetylglucosamine of the R II structure.     

Chiral separations by capillary electromigration techniques in nonaqueous media. II. Enantioselective nonaqueous capillary electrochromatography

A review on the advantages, peculiarities, and the potential of enantioselective capillary electrochromatography (CEC) in nonaqueous media is presented. Some fundamentals on CEC with particular focus on enantioselective CEC are discussed. The strategies, concepts, preferentially utilized chiral selectors and column technologies that have been utilized to succeed in highly efficient enantiomer separations by nonaqueous CEC are described thoroughly.     

芦荟中多糖的光度测定新方法

利用正交试验考察了芦荟多糖与刚果红显色反应的最佳条件；研究了麦芽糖糊精等多糖、蔗糖等低聚糖和葡萄糖等单糖对显色反应的影响；建立了简便快速、常见糖类基本无干扰的测定芦荟多糖含量的吸光光度法。对芦荟鲜叶和芦荟制品中的多糖进行分析，加标回收率在92％～96％范围内，相对标准偏差≤5％。     

党参花粉多糖的研究

从蜜峰采集的党参花粉中,分离到5种多糖CPA～CPE,经凝胶过滤及电泳法验证了纯度并测定了分子量。对CPA进行了全水解、甲基化分析、NalO_4氧化和Smith降解分析,用旋光法测定了CPA中单糖残基的绝对构型,对CPA的IR、~1H NMR、~(13)C NMR及~1H NMR、~(13)C偶合NMR进行了分析,确定了异头碳的构型。对CPA进行了电子显微镜分析,首次在透射电子显微镜下观察并拍摄到了具有串珠状特殊二级结构的多糖照片,经分析得到了CPA二级结构的一些信息。