沙棘果皮水溶性多糖H_n的结构研究

沙棘果皮水溶性多糖经酸性乙醇分级和DEAE -SephadexA - 2 5柱层析纯化 ,得到多糖Hn.经SepharoseCL - 4B柱层析、玻璃纤维纸电泳、比旋光度测定等方法鉴定Hn 为均一多糖 .经唾液淀粉酶解、部分酸水解、高碘酸氧化、Smith降解、甲基化分析及IR ,1 3C -NMR ,GC和GC -MS等方法 ,确定其基本结构中主链由 1→ 4Glc基、1→ 6Man基和 1→ 6Gal基构成 .三者摩尔比为nGlc∶nMan∶nGal=3∶1 .5∶1 ,分支点在 3—O处 ,分支率为 43% ,侧链由 1→ 6Gal基、1→ 4Glc基、末端Glc或末端Ara基构成 .     

肉苁蓉多糖SPA结构的GC-MS及13C-NMR分析

从野生肉苁蓉茎中提取水溶性多糖，经Seveg法和酶法脱蛋白，超滤分级及Sephadex G-75制备柱分级，得均一组份SPA．经甲基化及GC／MS，^13C-NMR分析证明SPA由(1→6)Glc组成主链，且Glc残基在3-O处有一分枝，侧链由(1→4)Gal，(1→4)Man，(1→3)Gal及(1→2)Rha组成，由(1→)Ara构成侧链末端．     

榆耳水溶性多糖的结构特征

用3%三氯醋酸从榆耳子实体中提取出水溶性粗多糖,经乙醇分级、SepharoseCL6B纯化得到单一组分GIA.SepharoseCL6B柱层析测得GIA的相对分子质量为1 26×105.GC分析表明GIA由Man和Glc两种单糖构成,其物质的量比为1 42∶1.多糖GIA经部分酸水解、高碘酸氧化、Smith降解和甲基化分析其结构主要为β(1→3)Man和β(1→3)Glc,且在6～0处构成分枝结构,平均每11个己糖残基有2个分枝,多糖GIA的支链部分由(1→4)Glc构成,末端残基为Man,Glc.     

玉米芯酸提水溶性多糖CCCP的分离纯化和结构研究

玉米芯用PH=3的HCl煮提得到酸提水溶性粗多糖．该粗多糖组成为Glc，Xyl，Gal，经乙醇分级和Sepharose CL-6B柱层析纯化，得到多糖CCCP．经Sephadex A-25柱层析、比旋光度测定、醋酸纤维薄膜电泳等方法鉴定CCCP为均一多糖．经唾液淀粉酶解、纤维素酶解、部分酸水解、高碘酸氧化、Smith降解、甲基化分析及IR，GC和GC／MS等方法分析表明：CCCP为少分枝结构；主链由吡喃型(1→3)Xyl构成，在O(4)处有分枝；支链主要由(1→4)Glc构成，在O(6)处有分枝，支链还存在1→3，1→6键型连接的Glc，Gal；末端基为Xyl，Glc，Gal．     

独脚金水溶性多糖的结构表征及其清除自由基活性

独脚金粗多糖(Strigaasiatica(L.)O.Ktze. polysaccharide,SKPc)经DEAE-Sephadex A-25以及Sephadex G-100柱层析分离纯化后得到独脚金多糖组分(SKP~*_1)。采用高效液相色谱(HPLC)法检测SKP~*_1,表明多糖SKP~*_1极性、相对分子质量是均一的,且其相对分子质量为14852u。采用气相色谱(GC)分析法研究SKP~*_1的单糖组成为葡萄糖(Glu)、阿拉伯糖(Ara)、半乳糖(Gal)、木糖(Xyl)、甘露糖(Man)、鼠李糖(Rha),相对摩尔比是2.5∶2.0∶0.85∶0.4∶0.5∶1.0;可能主要以β型糖苷键连接。采用化学分析和仪器分析结合进行SKP~*_1结构分析,表明SKP~*_1结构是Ara以β-(1→3)糖苷键连接构成主链之一,2,4或2,5位有支链;Gal以β-(1→6)糖苷键连接构成SKP~*_1的主链之一,且在3位上有分枝。支链由β-(1→4或1→5)Xyl、β-(1→4,1→6,1→2)Glc构成。Rha、Ara、Man、Gal、Glc都有一部分构成糖分子的末端残基。体外清除羟基实验结果表明,SKP~*_1有较好地清除羟基自由基的活性。     

小刺猴头菌子实体水溶性多糖HP Ⅱ的结构研究

小刺猴头菌子实体多糖经乙醇分级和Sepharose CL-6B柱层析，得到多糖HPⅡ．经Sephadex G-100柱层析，高压玻璃纤维纸电泳，比旋光度测定等方法鉴定：HPⅡ在相对分子质量大小和极性上都较为均一．经部分酸水解、高碘酸氧化、Smith降解、IR分析、甲基化分析、GC和GC／MS联机分析等方法，确定了其结构：（1→6）Glc构成主链的核心结构，在3-O处有分枝，平均每7个己糖残基有3个分枝残基；A，B为侧链结构，其构成成分为Glc和Gal；末端残基为（1→）Glc．     

Isolation,purification and structural characterization of a water-soluble polysaccharide HM41 from Halenia elliptica D. Don

A water-soluble polysaccharide, HM_(41), was obtained from Halenia elliptica D. Don by acidic ethanol fractionation and gel filtration. Its homogeneity was confirmed by chromatography using multiple systems. HM_(41) was composed of rhamnose(Rha), arabinose(Ara), xylose(Xyl), mannose(Man),galactose(Gal), glucose(Glc) with a molar ratio of 1.0:5.5:1.8:3.0:9.4:21. The average molecular weight of HM_(41) was approximately 1.17 * 10~4. Periodate oxidation, Smith degradation, methylation and GC, IR,NMR, XRD, GC–MS analysis were used for the structural analysis of HM_(41). Its main chain was composed mainly of β-(1→4)Gal, β-(1→4)Glc and β-(1→6)Glc. β-(1 →4)Gal were substituted at 6-O and on average there were 14 branches among 23 main chain residues;(1→ 4)Glc had no branch;(1→6)Glc were substituted at 3-O and on average there were 9 branches among 14 main chain residues. The side chain was composed of(1→3,6)-Rha,(1→4)/(1→5)-Ara,(1 →4)/(1→5)-Xyl,(1→4,6)-Man and(1→2)-Glc. The terminal residue was composed of Ara, Xyl, Man, Gal, and Glc. Then, we demonstrated that HM and HM_(41) had strong scavenging activities in vitro hydroxyl. Overall, HM and HM_(41) may have potential applications in the antioxidants for medical and food industry.     

榆耳水溶性多糖GIA的结构分析

用6%尿素从榆耳(Gloeostereuminsarnatum)子实体中提取出水溶性粗多糖,经乙醇分级及SeoharoseCL-6B制备柱收集得到组分GIA.经SephadexG-75、DEAE-阴离子交换纤维素和HPLC验证,GIA分子量及极性为均一组分.气相色谱(GC)分析表明,其单糖组成为Xyl,Gal和Glc.HPLC测得平均分子量为18000.经IR、GC、部分酸水解、高碘酸氧化、Smith降解、¹³CNMR、甲基化分析及其产物的GC-MS联机分析表明,GIA为少分支结构,主要由α型糖苷键构成,少部分由β型糖苷键构成;主体结构由Gal和Glc组成,其中主要为Gal1→6,还有Glc1→6;Gal1→6和Glc1→6在3-O处有分支;平均每10个己糖残基有2个分支;GIA的支链部分由Gal1→3和Glc1→3构成;末端残基为Xyl,Gal,Glc.     

松木层孔菌多糖PEP的结构及活性研究

从松木层孔菌发酵菌丝体中分离制备碱提水溶性多糖(PEP).高效液相色谱分析表明,PEP为单一级分,相对分子质量约为1.6×104.GC分析PEP的单糖组成为甘露糖、半乳糖和葡萄糖,其物质的量比为3.11∶1.32∶0.54.PEP经部分酸水解、高碘酸氧化、Smith降解和甲基化分析,其结构主要为β-(1→2)Man且在6-0处构成分枝结构,PEP的支链部分由(1→4)-Man,(1→6)-Gal构成,末端残基为Gal和Glc.初步考察,PEP对小鼠离体淋巴细胞有较显著的促增殖作用.     

Studies on Structure and Porperties of Water Soluble Polysaccharide from Fruiting Body of Cordyceps Militarvs(L.) Link

A water soluble crude polysaccharide has been isolated from the fruiting body of cultivated Cordyceps militarvs(L.)Link.The GC analysis indicated that it contained the monosaccharides of Gal,Man,Glc and GlcA.Their molar ratio is 1.00:1.58:7.89:0.19.The crude polysaccharide was fractionated with ethanol to get three fractions,which were CM-Ⅰand CM-Ⅲ,CM-Ⅱ was further purified to get one homogeneous fraction named CMB.The molecular weight was estimated to be 6000by means of gel filtration.CMB is a greyish white powder.The GC analysis indicated that it was composed of Gal.Man,Glc and the molar ratio is 1.00:1.38:5.10.Partial hydrolysis with an acid.periodate oxidation.Smith degradation.IR,GC and methylation analyses,GC/MS analyses were used for the structure analyses of CMB.Man,(1→6)-linked-Glc,(1→4)-linked-Glc and (1→4)-linked-Gal.Some of (1→4) -linked-Glc and all(1→4)-linked-Gal residues are substituted at 3-O and 6-O respectively,(1→4)-linked-Glc and minor(1→6)-linked-Gle.The nonreduced end is composed of Gal and Glc.The main glycosidic link of CMB is α configuration.     

Nanostructure of polysaccharide complexes

The interaction of gum arabic (GA) with chitosan (Ch) of different degree of deacetylation was studied by turbidity measurements, dynamic light scattering and atomic force microscopy. The structure of the complexes was found to be directly related to the charge density of chitosan molecules. Gum arabic and chitosan with a degree of deacetylation of 75% form soluble complexes with a loosely globular structure of about 250 nm, at weight ratios up to 1.2, if the concentrations are kept low (total biopolymer concentration up to 0.06%). If chitosan has a higher charge density (degree of deacetylation of 93%), colloidal particles are formed, independently of the polymer concentration or ratio. At low concentrations and GA/Ch ratios of 1 or 1.2, the particles have diameters of 200-250 nm. The formation of soluble complexes is attributed to a chitosan lower charge density and the presence of non-charged monomers, which prevent the efficient self-assembly of the macromolecules.     

Biological activities of biodegradable polysaccharide

A low toxicity of chitin was demonstrated to be mostly due to biodegradability and the fast metabolization of hydrolysate in animal body. Chitosan, a deacetylated derivative of chitin, is also known to be a biocompatible polymer in spite of a slight immunoadjuvant activity in animal body. Chitosan is easily regenerated to fiber, film, beads and non woven fabrics owing to its high solubility toward diluted aqueous organic acids such as formic acid, acetic acid, glutamic acid and ascorbic acid. The regeneration of chitin was achieved into fibers, gels, porous foams and non woven fabrics following to dissolution of chitin with formic acid or calcium chloride dihydrate saturated methanol. Chitin and its derivatives have been applied as biomedical materials due to remarkable advantages such as antimicrobial activity, acceleration of epidermal cell assembly, low toxicity, and biodegradability.     

Synthetic photocrosslinkable polysaccharide sulfates

Photoactive derivatives of dextran and pullulan with high degree of substitution were prepared by an efficient and mild esterification of the biopolymers with [(4-methyl-2-oxo-2H-chromen-7-yl)oxy] acetic acid via in situ activation of the carboxylic acid with N,N′- carbonyldiimidazole. Subsequently, sulfation was carried out with the gentle and easily manageable SO₃/DMF complex as reagent. Thus, water soluble polyelectrolytes decorated with high amounts of photochemically active moieties were obtained. The structures of the novel polysaccharide esters and the polyelectrolytes were evaluated by means of NMR and IR spectroscopy. Moreover, the photochemistry of both the carboxylic acid esters and their sulfated derivatives was studied by means of UV-Vis spectroscopy in the dissolved state. The changes observed may be used to control the properties and are thus of interest in the design of smart materials.     

Microrheology of polysaccharide nanogel-integrated system

The viscoelastic behavior of a cholesterol-modified pullulan (CHP) nanogel at various concentrations was measured using passive particle-tracking microrheology. Microrheology measures stress–strain relationships in small volumes of material by monitoring the response of probes embedded in the medium. Although microrheology is a useful way to overcome sample volume limitations, the application of the method to CHP nanogel systems has not been reported. The viscoelastic spectra of the CHP nanogels obtained from the microrheological measurements were in good agreement with the bulk rheological measurements for each sample, demonstrating that microrheological measurement is effective in CHP nanogel systems. The gelation behavior of CHP nanogel dispersions containing pullulans of different molecular weights was also investigated by microrheology. CHP nanogels made from 1.0 or 4.0?×?10⁵ molecular weight pullulans formed a macrogel at around 3.0 wt%, whereas the CHP nanogel consisting of 0.55?×?10⁵ molecular weight pullulan did not form a macrogel. This suggests that the mechanical properties of the system can be controlled by the molecular weight of the pullulan used. These insights into gelation behavior should be useful in predicting the most favorable conditions for developing novel materials.     

RAFT mediated polysaccharide copolymers

Graft copolymers were prepared using the RAFT process via a Z-group approach, where xanthate esters were formed directly on a cellulosic substrate. Grafting of vinyl acetate onto the modified cellulosic materials was then carried out via the reversible addition fragmentation chain transfer (RAFT) process. The xanthate RAFT agents on the backbone of the cellulosic materials were identified by Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectroscopy (UV-vis). The number average molar masses of the graft copolymers were determined using size exclusion chromatography (SEC) and further characterization was conducted via liquid adsorption chromatography (LAC). The chromatographic results showed that the modified cellulosic materials were successfully grafted with polyvinyl acetate in a controlled manner. Grafted polyvinyl acetate (on the surface) and nongrafted polyvinyl acetate (in the solution) have almost the same molar mass and polydispersity index.     

玉米芯碱提水溶性多糖及其硫酸酯抗病毒活性的研究

从玉米芯中,用2%NaOH提取,HCl中和,经乙醇醇析,制备碱提水溶性多糖.用氯磺酸吡啶法修饰制备多糖硫酸酯.离子色谱法测其硫酸根含量为11.23%.玉米芯多糖经硫酸化修饰后对柯萨奇病毒(Coxsackie B3Virus)有一定的抑制作用,但对人全血凝血时间无显著影响.     

Synthesis and aminolysis of polysaccharide carbonates

Well soluble dextran-, cellulose-, starch-, and pullulan aryl carbonates were synthesized applying p-NO₂-phenyl chloroformate, phenyl chloroformate, and phenyl fluoroformate. Aminolysis of the products obtained, using aliphatic amines or benzyl amines, yield novel soluble polysaccharide carbamates. The influence of the reaction conditions on the reaction efficiency depending on polysaccharide, reagent, and reaction parameters including temperature was studied. Thus a synthesis strategy was developed for the easy and efficient design of structures of polysaccharide-based materials. The products were characterized by means of NMR-, UV-Vis- and FTIR spectroscopy, elemental analysis, and size exclusion chromatography.