灵芝多糖的提取方法及其功能特性研究进展

首先对灵芝多糖的初级结构和高级结构进行了介绍;其次对近年来研究灵芝多糖的热水提取法、超声波提取法、微波提取法、酶提取法等提取方法进行了综述和比较;最后对灵芝多糖的抗氧化、抗肿瘤、降血糖等功能特性进行了阐述。     

两种提取枸杞多糖方法的比较研究

通过正交实验对热水浸提法和微波提取法提取枸杞多糖进行了比较研究。热水浸提法提取枸杞多糖的最佳工艺条件为：提取温度70℃、提取时间4h、料液比1∶20（g∶mL）、提取次数3次,提取率为4.51%;微波提取法提取枸杞多糖的最佳工艺条件为：微波功率560W、微波时间90s、料液比1∶10（g∶mL）、提取次数3次,提取率为5.91%。微波提取法时间短、能耗小、提取溶剂用量少、提取率高,优于热水浸提法。     

多糖的高级结构鉴定分析的研究进展

多糖是自然界中普遍存在的生物大分子，具有多种药理活性，多用于功能性食品和治疗剂。多糖的生物活性取决于其化学结构，本文介绍了二维核磁共振（2D NMR）、X-射线衍射法、毛细管电泳-质谱联用技术（CE-MS）、基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）、圆二色光谱（CD）、扫描电子显微镜（SEM）、原子力光谱（AFM）、差示扫描量热法（DSC）以及分子动力学模拟技术等多糖分析鉴定方法，并对今后的研究工作进行了展望。     

电镀液中铑含量的不同分析方法

对标准浓度的铑溶液进行了重量法、等离子发射光谱法（ICP）、火焰原子吸收光谱法（FAAS）、改进后的FAAS（引入一个校正因子, 对FAAS测定方法进行了优化、校正）等不同方法的测定,比较了不同测定方法的精密度和准确度.结果表明：对于杂质少的铑电镀液,宜采用重量法测定,其测定偏差在4％以内,而硼氢化钠作为还原剂的重量法的测定偏差可控制在0.2%以内;对于杂质多的铑电镀液,用ICP和改进的FAAS法均能获得满意结果,相对偏差都小于1%.     

改性香菇多糖铁(Ⅲ)配合物的制备及其应用研究

采用95%乙醇对香菇粉进行脱脂预处理后,再用超声波法提取香菇多糖(LNT)。为提高其水溶性,采用过氧化氢氧化法对提取的香菇多糖进行化学改性。探究了过氧化氢浓度、pH值、改性时间等因素对改性香菇多糖(MLNT)水溶性的影响。利用傅里叶变换红外光谱和X射线粉末衍射技术对改性香菇多糖进行了结构表征。结果表明,改性后香菇多糖的分子结构发生改变,其水溶性以及与Fe(Ⅲ)的配位能力增强。采用共振散射技术研究了改性香菇多糖与三价铁离子的配位作用,并考察了反应介质、pH值、改性多糖用量等因素的影响。在最优实验条件下,在0.40~6.0μg/mL范围内,体系的共振散射强度变化值ΔI与Fe(Ⅲ)浓度之间有一定的线性关系,其检出限为0.81 ng/mL。据此,分别分析测定了矿渣和布袋灰中的铁含量,相对标准偏差为3.8%和3.4%,回收率为102%和112%。     

活性多糖构效关系研究评述

从结构与活性、理化性质与活性两个角度分别对活性多糖的构效关系进行论述。影响多糖生物学活性的结构因素包括多糖的主链性质、支链性质和多糖分子的高级结构 ,其中多糖主链的糖单元组成、糖苷键类型均直接决定多糖的活性 ,多糖支链的类型、聚合度、支链在多糖链上的分布及其取代度决定了多糖活性大小 ,多糖分子的高级结构如链的柔韧性和空间构像与多糖的活性紧密相关。多糖的理化性质如分子质量、溶解度和黏度等在一定程度上影响多糖活性的发挥     

两种方法提取琉璃苣叶多糖的理化性质 及生理活性

本研究旨在制备两种琉璃苣叶水溶性多糖，进一步探究其结构特征，并评价其降血糖、抗癌和免疫活性。采用纤维素酶辅助提取（BLP-1）和微波辅助提取法（BLP-2）制备琉璃苣叶水溶性多糖，并比较了BLP-1和BLP-2的理化性质，通过分析α-葡萄糖苷酶和α-淀粉酶的抑制效果来评价BLP-1和BLP-2的降血糖活性，通过检测HepG2、MX-1和A549细胞的抑制率来评价抗癌活性，通过检测RAW246.7的免疫因子分泌来评价免疫活性。结果表明，BLP-1和BLP-2具有不同的多糖和蛋白质含量。BLP-1和BLP-2由阿拉伯糖（Ara）、半乳糖（Gal）、葡萄糖（Glc）、木糖（Xyl）组成，但摩尔比组成不同，其分子量分别为20.1和22.6KDa。热重分析（TGA）表明BLP-2比BLP-1具有更稳定的结构。这两种多糖具有抑制α-葡萄糖苷酶和α-淀粉酶活性、抑制HepG-2、A549和MX-1癌细胞增殖以及激活巨噬细胞RAW 264.7细胞分泌免疫细胞因子以介导细胞免疫反应的潜力。两种多糖可作为新功能食品和医药产品中的生物活性成分，为进一步研究两种多糖的构效关系提供了理论依据。     

响应曲面法优化刺山柑水溶性多糖提取工艺及其抗氧化性能研究

以刺山柑果实为原料,在单因素实验的基础上,选择提取温度、提取时间和液料比为影响因子,以刺山柑水溶性多糖提取率为响应值,应用Box-Behnken中心组合方法建立数学模型,利用响应曲面法确定超声辅助提取刺山柑水溶性多糖的优化工艺条件为：提取温度85℃、提取时间89 min、液料比30∶ 1（mL∶g）,在此条件下刺山柑水溶性多糖平均提取率为8.89％.提取得到的刺山柑水溶性多糖对羟基自由基（·OH）和超氧阴离子自由基（·O2-）均有一定的清除作用,具有一定的抗氧化活性.     

响应面法优化发酵猴头菇多糖提取工艺研究

为了考察益生菌发酵真菌产水溶性多糖的最佳提取工艺,以猴头菇为原料,格氏乳杆菌为发酵菌株,以发酵猴头菇多糖提取率为指标,研究了发酵时间、发酵温度以及接菌量对发酵猴头菇多糖提取率的影响。本研究利用水提醇沉提取法,在单因素实验的基础上,采用响应面法对发酵条件进行了优化。结果表明,提取发酵猴头菇多糖的最佳条件为发酵温度为35℃,发酵时间为45.5h,接菌量为4.2%,此条件下多糖提取率为（6.39±1.27）%。本研究为提取发酵猴头菇多糖提供了理论依据。     

核磁共振波谱法在双价痢疾多糖结合疫苗中的初步应用

目的探讨核磁共振波谱(nuclear magnetic resonance,NMR)法在福氏宋内双价痢疾多糖结合疫苗生产工艺中的应用。方法利用Agilent 600 MHz核磁共振仪分别对福氏2a痢疾多糖和宋内痢疾多糖重复结构单元进行1H NMR和13C NMR质量分析,并对生产工艺中的多糖、多糖衍生物及多糖结合物重复结构单元进行了1H NMR结构解析和对比。结果多糖的1H NMR和13C NMR数据及图谱与文献高度一致;结合工艺中各步多糖的1H NMR分析证实了双价痢疾多糖结合工艺的反应机理。结论在双价痢疾多糖结合疫苗的研发过程中,NMR法可直接地检测多糖化学结构,对原料多糖及整个衍生过程中多糖的结构及修饰程度实施质控。     

Some substituted polysaccharides as low temperature middle distillate additives

Substituted polysaccharides with different molecular weights (mol. wt 12 000–15 500) were synthesised by reacting aliphatic acid chlorides with different carbon numbers (C₁₂-C₁₈) with dextrin. The resulting polymers were purified and tested as pour point depressants and flow improvers for middle distillates (gas oils). Comparative evaluation of these polysaccharides with some commercial additives showed their good activity, especially as flow improvers.     

Effect of polysaccharides on the hydration of cement paste at early ages

This work deals with the relative efficiency of polysaccharides and their influence on cement hydration. Several parameters such as the structure, concentration, average molecular weight, and soluble fraction value of polysaccharides were examined. Cement hydration was monitored by isothermal calorimetry, thermogravimetry (TGA), and Fourier transform infrared (FTIR) spectroscopy. Results clearly show that retardation increases with higher polysaccharide-to-cement weight ratio (P/C). Low-molecular-weight starch showed enhanced retarding effect on the hydration of cement. The retardation effect of polysaccharides is also dependent on the composition of cement.     

灵芝茵丝体多糖的超滤提取及其抗氧化活性的研究

考察了超滤浓缩醇沉法提取发酵灵芝茵丝体多糖,与减压浓缩法相比,多糖含量、多糖得率均高于后者,所得多糖的品质得到提高,减轻了后续多糖纯化的负担.灵芝菌丝体粗多糖对羟自由基·OH(HFR)有较好的清除能力,在一定范围内清除率与多糖浓度呈正相关,超滤浓缩醇沉法提取灵芝茵丝多糖的·OH清除率高于减压浓缩醇沉法.     

灵芝菌丝体多糖的超滤提取及其抗氧化活性的研究

考察了超滤浓缩醇沉法提取发酵灵芝菌丝体多糖,与减压浓缩法相比,多糖含量、多糖得率均高于后者,所得多糖的品质得到提高,减轻了后续多糖纯化的负担。灵芝菌丝体粗多糖对羟自由基.OH(HFR)有较好的清除能力,在一定范围内清除率与多糖浓度呈正相关,超滤浓缩醇沉法提取灵芝菌丝多糖的.OH清除率高于减压浓缩醇沉法。     

Poiy(hexamethyienebigyanidiniym chloride) as a reagent for the determination of water-soluble naturai carboxylate and sulphate polymers

The poly(hexamethylenebiguanidinium chloride) [PHMBH ⁺ Cl^?] assay method developed originally for sodium alginate determination in solution (0 01-0 5 %) has been applied to a wide range of other acidic polysaccharides. The simple procedure consists of the addition of a known excess of PHMBH ⁺ Cl^? to precipitate the sample quantitatively and thereafter measuring the u.v. absorption of residual PHMBH ⁺ Cl^? in the supernatant. Response to the method is dependent upon the acidic group-monosaccharide molar ratio and can be conveniently altered for polysaccharides with different anionic charge densities by simple adjustment of assay conditions. For acidic polysaccharides with very low charge densities, such as propylene glycol alginates with a high degree of esterification, the response to the assay can be increased by addition of borate ions which complex with the polymer molecules to increase the negative charge. The electrostatic nature of the response also allows the assay method to be used for the determination of extent of esterification in propylene glycol alginates with up to ～70% derivatisation. The method has been shown to be suitable for low molecular weight samples. Therefore, it is more reliable than other assay methods for acidic polysaccharides which involve a precipitation step with doubtful quantitative recovery for low molecular weight material. The simplicity, rapidity and reliability of the method makes it a suitable procedure for both carboxylated and sulphated polysaccharides in a range of applications.     

Chemical synthesis of polysaccharides and polysaccharide mimetics

Polysaccharides are ubiquitous in nature, and play many critical roles in biology. As such, the synthesis of polysaccharides and of polymers mimicking the structure or function of polysaccharides is of keen interest in order to reveal structure-function relationships and to prepare biocompatible and biodegradable materials for research and commercial applications. Recent developments in polymerization methodologies are enabling the synthesis of polysaccharides and polysaccharide mimetics with a variety of structures and architectures. While there have been significant advances in overcoming the difficulties in controlling the regioselectivity and stereospecificity of glycosidic bond formation during polymerization, the development of efficient synthetic routes with general applicability to stereoregular and structurally complex polysaccharides remains a challenge. This review comprehensively describes the chemical polymerization methods to synthesize polysaccharides with different compositions and architectures (linear, branched, and hyperbranched) and the synthetic procedures to polysaccharide mimetics possessing, for example, amine linkages, amide linkages, and carbonate linkages. It begins with a discussion of the challenges and strategies for the synthesis of polysaccharides. We highlight the complexity observed in theses macromolecules due to the number and variety of stereo- and regio-types of glycosidic linkages present between monosaccharide residues. With regards to polysaccharide mimetics, we focus on polymers displaying important structural features present in natural polysaccharides, such as a rigid polymer backbone containing heterocyclic ring structures, short linkages with less than three atoms, as well as multiple hydroxyl groups. Both condensation polymerization and ring-opening polymerization are used to prepare linear polysaccharides, branched polysaccharides, hyperbranched polysaccharides, non-O-glycosidic linked polysaccharide mimetics, and pseudopolysaccharides. The review concludes with reflections and suggestions for future directions of investigation.     

Main properties and current applications of some polysaccharides as biomaterials

This review concerns the applications of some polysaccharides in the domain of biomaterials and bioactive polymers. Natural polysaccharides from different sources have been studied for a long time, and their main properties are summarized in this paper; some of their derivatives obtained by chemical modification are also described. The main polysaccharides currently used in the biomedical and pharmaceutical domains are chitin and its derivative chitosan, hyaluronan and alginates. Alginates are well known for their property of forming a physical gel in the presence of divalent counterions (Ca, Ba, Sr) whereas carrageenans form a thermoreversible gel; these seaweed polysaccharides are mainly used to encapsulate different materials (cells, bacteria, fungi). Other promising systems are the electrostatic complexes formed when an anionic polysaccharide is mixed with a cationic polysaccharide (e.g. alginate/chitosan or hyaluronan/chitosan). An important development of the applications of polysaccharides can be predicted for the next few years in relation to their intrinsic properties such as biocompatibility and biodegradability in the human body for some of them; they are also renewable and have interesting physical properties (film‐forming, gelling and thickening properties). In addition, they are easily processed in different forms such as beads, films, capsules and fibres. Copyright © 2007 Society of Chemical Industry     

Grafted polysaccharides based on acrylamide and N,N‐dimethylacrylamide: Preparation and investigation of their flocculation performances

The graft copolymerization of N,N‐dimethylacrylamide (DMA) and acrylamide (AM) were carried out onto different polysaccharide backbones separately. The graft copolymers were synthesized by ceric ion induced redox polymerization technique. Three polysaccharides were used, namely hydroxyethyl starch (HES), hydroxyethyl cellulose (HEC) and Amylopectin (AP), for the grafting reactions. Among the three polysaccharides, HEC has linear structure, while HES and AP have a branch one. The graft copolymers were characterized by intrinsic viscosity measurements, FTIR spectroscopy, NMR (both ¹H and ¹³C) spectroscopy, and thermal analysis. Flocculation performances of the graft copolymers were evaluated in 1 wt % kaolin and in 0.25 wt % iron ore suspensions. A detailed comparative study of the flocculation properties of the synthetic graft copolymers was also made. It showed that graft copolymers based on DMA were better flocculants than those based on AM. Among the synthetic graft copolymers, HES‐g‐Poly (DMA) performed best when compared with the other synthetic graft copolymers as well as to the commercial flocculants in the same suspensions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

CXC Chemokine Signaling in Progression of Epithelial Ovarian Cancer: Theranostic Perspectives

Patients with epithelial ovarian cancer (EOC) are often diagnosed at an advanced stage due to nonspecific symptoms and ineffective screening approaches. Although chemotherapy has been available and widely used for the treatment of advanced EOC, the overall prognosis remains dismal. As part of the intrinsic defense mechanisms against cancer development and progression, immune cells are recruited into the tumor microenvironment (TME), and this process is directed by the interactions between different chemokines and their receptors. In this review, the functional significance of CXC chemokine ligands/chemokine receptors (CXCL/CXCR) and their roles in modulating EOC progression are summarized. The status and prospects of CXCR/CXCL-based theranostic strategies in EOC management are also discussed.     

Influence of the initiator system, cerium-polysaccharide, on the surface properties of poly(isobutylcyanoacrylate) nanoparticles

Isobutylcyanoacrylate has been used to form nanoparticles in presence of polysaccharides by two methods of polymerization. To have a better understanding of the relation between the structure of the resulting copolymer and the surface properties of the nanoparticles, the redox radical emulsion polymerization (RREP) was investigated and compared to anionic emulsion polymerization developed by Couvreur et al. (AEP Couvreur). The kinetic study showed that at pH1 the nanoparticles were formed in 5 min by RREP against 30 min in anionic emulsion polymerization (AEP pH1). The diameter of the nanoparticles was mainly affected by the concentrations of cerium and dextran and by the molecular weight of the dextran. The zeta potential was controlled by the characteristics of the polysaccharides (molecular weight and charge). The different methods of polymerization of isobutylcyanoacrylate led to nanoparticles with different surface properties.