金顶侧耳酸提水溶性多糖的研究——PC-3的分离、纯化与结构确定

金顶侧耳(Pleurotus citrinopileatus)子实体的3%三氯乙酸提取液经甲醇分级,十六烷基三甲基溴化铵等进一步提纯得到水溶性多糖PC-3。经Sepharose CL-4B柱层析,醋酸纤维素薄膜电泳、聚丙烯酰胺凝胶电泳鉴定,PC-3为均一级份。G.C.与P.C.分析表明,Gal、Man为该多糖的组份,其单糖摩尔比为2.5∶1.0。PC-3的分子量约为67000,比旋光度[α]_D~(18°)=+28°。经核磁共振谱等分析,PC-3不含β型糖苷键。部份酸水解、高碘酸氧化、Smith降解、完全甲基化、G.C.及G.C.-M.S.的分析表明,PC-3是由α(1→6)糖苷键相连的半乳糖构成分子的主链,部分残基C_2上带有分支,每5个Gal残基带有1个侧链,侧链为α(1-2)Man-α(1-2)Man。     

大马勃水溶性多糖的结构研究

采用热水浸提,乙醇沉淀的方法得到大马勃粗多糖,经Sevag法脱蛋白,DEAE—sepharose fast flow离子交换层析及sephacrylS-300HR凝胶过滤法得大马勃多糖（CGPI-1）。气相色谱研究表明,其单糖组成为：Gal,Glc,Man等四种单糖,其中Gal,Glc,Man,摩尔比为3．92：11．28：1．22。经部分酸水解,红外光谱及核磁共振光谱,高碘酸氧化,Smith降解等分析,CGPI-1的主链由Man和Glc构成,存在β型和α型两种糖苷键构型,支链或主链的末端残基由β-Gal（1→4）,β-Glc（1→6）,α—Glc（1→4）构成,其分子中存在酰胺结构。原子力显微镜观察发现CGPI-1呈分支的线性分子,在水溶液中容易互相缠绕形成强大的网络结构。     

两种灵芝孢子粉多糖的分离纯化和结构

本文采用水提醇沉法从灵芝孢子粉中提取其粗多糖,经Sepharose CL-6B凝胶柱层析分离得两种主要成分LBPI和LBPII,经高效液相色谱鉴定,均为高均一性成分,分子量分别为9.17×10 ⁴和1.86×10 ⁴;经酸水解、乙酰化和气相色谱分析,确定LBPI的单糖组成为甘露糖、半乳糖和葡萄糖,LBPII的单糖组成为鼠李糖、甘露糖、半乳糖和葡萄糖;通过高碘酸氧化、甲基化和GC-MS进行结构分析,确定LBPI中葡萄糖残基连接方式为1→、1→4,6和1→3,6连接,半乳糖残基为1→6连接,甘露糖残基为1→3,6连接,LBPII中鼠李糖残基连接方式为1→连接,葡萄糖残基为1→、1→4、1→6、1→4,6和1→3,6连接,半乳糖残基为1→6连接,甘露糖残基为1→2,3,6连接。综上,两种多糖LBPI和LBPII均为多分支的中型杂多糖,但两者的单糖组成和连接方式存在差异,这两种多糖成分均为首次报道,可望为灵芝孢子粉的成分、活性研究和资源开发提供理论依据。     

东北红豆杉多糖的化学研究

利用水提醇沉提取东北红豆杉多糖TP,经超滤得到超滤外液TP-1和内液TP-2。TP-2进行部分酸水解和凝胶柱层析分离纯化,得到TP-2-1a。通过对理化性质、分子量、单糖组成和甲基化测定结果分析,确定其分子量分布在7.0 kDa左右,糖组成由Rha、Man、Gal、Glu、GalA和GlcA构成,摩尔比为:16.9∶1.0∶15.5∶1.3∶9.9∶2.5,中性糖以Gal的1→3、1→4连接为主,在1→3连接的O-6位上有分支;Rha以1→2连接为主,在O-4位上有分支;Man以1→4、1→6连接为主;Glu以1→3、1→4连接为主;非还原末端主要是Gal及少量的Man、Glu和Rha。酸性糖以1→4连接GalA为主,无分支。该多糖为首次从东北红豆杉中分离得到。     

刺五加果水溶性多糖的研究——AS-2的分离纯化与结构探讨

从刺五加果中抽提出水溶性粗多糖。经酸性乙醇分级及反复冻融得到多糖AS-2。AS-2经Sepharose CL-4B柱层析为单一对称峰,经醋酸纤维素膜电泳为一条带,冻融后高速离心无沉淀可证明其为均一级分。G.C分析表明,AS-2由Ara、Xyl、Rha、Gal、Glc组成,其单糖摩尔比为1.6:1.2:1.8:1.0:3.6。AS-2的分子量约为78kD,比旋光度[α]_D~(25)=+17°,特性粘度[η]=0.068。红外光谱分析含β型糖苷键。部分酸水解、酶解、高碘酸酸化、Smith降解、完全甲基化、G.C,G.C-M.S的分析结果表明,以β(1→3)Glc及β(1→4)Glc构成分子的主链。Glc的C_3上带有分支,约每4个己糖残基带有1个侧链。侧链上,Rha多以1→4苷键相连,部分残基C_2上有分支。Gal存在(1→6)及(1→3)连接方式,多数Glc以(1→6)苷键连结,少数Glc出现在分子非还原末端。位于分子末端的还有Ara与Xyl。     

蜗牛黏液多糖的提取、表征及抗氧化性和免疫活性

利用高效凝胶色谱串联紫外、示差和多角度激光散射检测器(HPSEC-UV-RI-MALLS)对蜗牛黏液中的多糖进行分子量分布表征。利用气相色谱串联质谱(GC-MS)和红外光谱(FT-IR)对其化学结构进行表征;并对所获得的多糖进行抗氧化及免疫活性的评价。结果显示:蜗牛黏液中主要含有5个组分的多糖,是其重要的活性成分。对这5个多糖进行鉴定,其平均分子量为4.549×10~6、1.392×10~5、6.291×10~4、5.262×10~(4 )和4.153×10~(4 )。单糖由岩藻糖、甘露糖、葡萄糖和半乳糖组成,摩尔比为1.69∶2.46∶0.12∶1。多糖主链为→2) Manp-(1→,→3) Fucp-(1→和→3) Manp-(1→。此外,蜗牛黏液多糖具有明显的抗氧化作用,能很好地清除ABTS·~+和·OH,IC_(50)值分别为2.35和4.70 mg/mL;且能明显增强巨噬细胞(RAW264.7)的吞噬能力,促进NO和白细胞介素(IL-6)、肿瘤坏死因子(TNF-α)等免疫细胞因子的释放。     

海洋红细菌Lentibacter algarum胞外多糖的分离纯化及结构解析

从青岛潮间带的海水中分离得到的红细菌科细菌Lentibacter algarum的发酵液中提取胞外多糖,对其进行离子交换色谱分离纯化,得到水洗和0.1、0.5、1.0 mol/L NaCl溶液4个洗脱组分。对含量最高的0.1 mol/L NaCl洗脱组分La0.1进行进一步的凝胶排阻柱层析纯化,得到组分La0.1-1。通过化学测定和高效液相色谱(HPLC)、高效凝胶渗透色谱法(HPGPC)等分析方法对其理化性质、分子量、单糖组成、连接方式及初步结构进行研究。结果表明,La0.1-1总糖含量为66%,平均分子量为12.0 kDa。其单糖组成主要为半乳糖、甘露糖和氨基葡萄糖,比例为Gal∶Man∶GlcN=1.35∶1.1∶1.0。对La0.1-1进行气相色谱质谱联用(GC-MS)和一维核磁(1-D NMR)分析结果显示,La0.1-1的连接方式是以β构型为主,主要存在→2)-Manp(1→,→3)-Galp(1→连接,还存在少量的→4)-Galp(1→和→4)-Manp(1→等连接方式,表明该多糖以直链为主,还存在一定的分支,分支发生在→2)-Manp(1→的O-6位和→3)-Galp(1→的O-4或O-6位。氨基葡萄糖主要为→4)GlcN(1→和末端连接方式。核磁分析还显示La0.1-1存在一定的乙酰基取代,初步判断主要取代在氨基葡萄糖的N-2位上,也可能存在于甘露糖和半乳糖上。本研究是首次对Lentibacter属细菌的胞外多糖进行测定,获得了结构较为新颖的胞外多糖资源,为开发海洋多糖资源提供物质基础。     

人参叶水溶性多糖——杂多糖P_N的纯化与结构初步确定

 从人参叶中提取的水溶性多糖经分离纯化得杂多糖P_N。P_N的分子量约为190万,单糖组成为阿拉伯糖、鼠李糖、木糖、半乳糖醛酸、半乳糖、葡萄糖及少量未知糖,单糖的摩尔比依次为8.1:0.8:1.0:1.6:12.5:4.1(未知糖除外)。经超离心分析,琼脂糖4B柱分析,玻璃纤维纸电泳和醋酸薄膜电泳鉴定等证明P_N为均一组份。经果胶酶降解,部分酸水解,高碘酸盐氧化,Smith降解,甲基化及其产物气相色谱(GLC)、气相色谱-质谱联用(GLC-MS)等结构分析表明P_N为多分支结构,分子的主链主要是由β-(1→3)连接的半乳糖组成,并在4—0和6—0上带有分支,平均每三个半乳糖有二个分支。     

猴头菌水溶性多糖的分离纯化与结构表征

从猴头菌子实体中分离得到一种新型的水溶性杂多糖HEPF2,分子量大小为1.66′104Da,该多糖由岩藻糖、半乳糖和葡萄糖以1.00:3.69:5.42比例构成,同时也含有微量的3-O-甲基鼠李糖。进一步利用傅立叶变换红外光谱法、糖组成分析、甲基化分析、部分酸水解法和核磁共振法等方法进行结构鉴定,检测结果表明,该杂多糖中包含1→4、1→6结合的葡萄糖和1→6结合的半乳糖残基,连接于主链的侧链残基,包括岩藻糖残基、少数的端基葡萄糖和半乳糖残基。核磁共振法检测结果还表明,1→4结合葡萄糖为β构型,(1→6)结合半乳糖、(1→2,6)结合半乳糖和端基葡萄糖均为α构型。     

金顶侧耳多糖PC-4的结构确定与抗肿瘤活性的研究

从3％三氯乙酸浸提过的金顶侧耳(Pleurotus citrinopileatus)子实体中分离纯化另一水溶性多糖PC-4。该多糖分子量约为189Kd。纸层析与气相层析分析表明其为单一葡聚糖。经高碘酸氧化,Smith降解,甲基化,气相层析,气质联机分析,核磁共振(~1H-NMR,~(13)C-NMR)谱及红外光谱测定等,可确定PC-4的主链结构由β(1→3)糖苷键相连的葡萄糖构成,部份残基C_6上带有分支。约每5个糖残基有两个侧链,侧链仅为1个葡萄糖残基。 给ICR小鼠腹腔注射PC-4,对移植性肿瘤S-180有一定的抑制作用,抑瘤率为67％。离体条件下,PC-4与肿瘤细胞S-180共同培养,则未显示抑瘤作用。     

The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos

The endosperm of the seed of Gleditsia triacanthos contains 4.8% of 85% ethanol-soluble, galactomannan-like oligosaccharides having Man:Gal ratios of 1.5–2.6:1 and an average degree of polymerization of 15. They have a narrow distribution of molecular weights and of ratio of components. The oligosaccharides have the gross structure accepted for the galactomannans, namely, a β-(1→4)-linked d-mannopyranosyl backbone having single stubs of α-(1→6)-linked d-galactopyranosyl groups. Some of the lateral chains contain more than one unit, and a minor proportion of the branches are ended by arabinofuranose or fucopyranose residues. Unusual branching points formed by 3,4-linked d-mannosyl, or 3,6-linked d-galactosyl units, or both, were also found. Despite their low molecular weight, the oligosaccharides form aggregates with a structure similar to that of the aggregates of the related galactomannans, but having a lower association energy. This fact, together with the difficulty of combining with more than one partner (due to the short, central chain), results in an increased solubility and in nonviscous solutions. The ¹³C-n.m.r. spectrum differentiated clearly the five structural units of the oligosaccharides, namely, the reducing and nonreducing end-chains of the d-mannosyl backbone; substituted and nonsubstitued, internal β-(1→4)-linked mannopyranosyl units of the backbone; and the galactosyl nonreducing end-chain of the lateral chains. The C-4 signal of the (1→4)-linked d-mannose and the C-6 signal of the same, but substituted, units showed splitting into three lines. The first has been attributed to sequence-related heterogeneity, whereas the latter is tentatively explained by assuming that this resonance is sensitive to whether the mannosyl units linked to that residue are also branched, or not.     

Structural elucidation of an α-1,2-mannosidase resistant oligosaccharide produced in Pichia pastoris

The N-glycosylation pathway in Pichia pastoris has been humanized by the deletion of genes responsible for fungal-type glycosylation (high mannose) as well as the introduction of heterologous genes capable of forming human-like N-glycosylation. This results in a yeast host that is capable of expressing therapeutic glycoproteins. A thorough investigation was performed to examine whether glycoproteins expressed in glycoengineered P. pastoris strains may contain residual fungal-type high-mannose structures. In a pool of N-linked glycans enzymatically released by protein N-glycosidase from a reporter glycoprotein expressed in a developmental glycoengineered P. pastoris strain, an oligosaccharide with a mass consistent with a Hexose(9)GlcNAc(2) oligosaccharide was identified. When this structure was analyzed by a normal-phase high-performance liquid chromatography (HPLC), its retention time was identical to a Man(9)GlcNAc(2) standard. However, this Hexose(9)GlcNAc(2) oligosaccharide was found to be resistant to α-1,2-mannosidase as well as endomannosidase, which preferentially catabolizes endoplasmic reticulum oligosaccharides containing terminal α-linked glucose. To further characterize this oligosaccharide, we purified the Hexose(9)GlcNAc(2) oligosaccharide by HPLC and analyzed the structure by high-field one-dimensional (1D) and two-dimensional (2D) (1)H NMR (nuclear magnetic resonance) spectroscopy followed by structural elucidation by homonuclear and heteronuclear 1D and 2D (1)H and (13)C NMR spectroscopy. The results of these experiments lead to the identification of an oligosaccharide α-Man-(1 → 2)-β-Man-(1 → 2)-β-Man-(1 → 2)-α-Man-(1 → 2) moiety as part of a tri-antennary structure. The difference in enzymatic reactivity can be attributed to multiple β-linkages on the α-1,3 arm of the Man(9)GlcNAc(2) oligosaccharide.     

Growth-inhibitory activity of the d-mannan of saccharomyces cerevisiae X2180-1A-5 mutant strain against mouse-implanted sarcoma 180 and ehrlich-carcinoma solid tumor

The d-mannan of Saccharomyces cerevisiae X2180-1A-5 mutant strain, which possesses a main chain composed of α-(1→6) linked d-mannopyranosyl residues and a small proportion of branches composed of α-(1→2)- and α-(1→3)-linked d-mannopyranosyl residues, showed strong growth-inhibitory activity against mouse-implanted Sarcoma 180 and Ehrlich-carcinoma solid tumor. The observation that the level of this activity was nearly identical with that of the d-mannan of a wild-type strain of bakers' yeast, which possesses a high proportion of branches composed of α-(1→2)- and α-(1→3)-linked d-mannopyranosyl residues, suggests that the branches are not essential for antitumor activity. The partial acid-degradation products of both d-mannans, the molecular weight of which was one-third of that of each parent d-mannan, had only one half of the antitumor activity of the parent d-mannans. This suggests that molecular size is the most important factor for the differences in activity of the polysaccharides of wild and mutant strains.     

Structure elucidation and antioxidant activity of a novel polysaccharide isolated from Boletus speciosus Forst

In this study, a novel heteropolysaccharide was isolated from the fruiting bodies of Boletus speciosus Forst through DEAE-cellulose column and Sephadex G-200 column. The Boletus speciosus Forst polysaccharide (BSFP-1) had a molecular weight of 1.33×10(4) Da and was mainly composed of l-Man and d-Gal which ratios were 2:1. Structural features of Boletus speciosus Forst polysaccharide (BSFP-1) were investigated by a combination of total hydrolysis, methylation analysis, gas chromatography-mass spectrometry (GC-MS), infrared (IR) spectra and nuclear magnetic resonance (NMR) spectroscopy. The results indicated that Boletus speciosus Forst polysaccharide (BSFP-1) had a backbone of (1→4)-α-l-mannopyranose residues which branches at O-6 based on the experimental results. The branches were mainly composed of one with →1)-α-d-galactopyranose residue. The antioxidant activity of BSFP-1 was evaluated with two biochemical methods, including 1,1-diphenyl-2-picrylhydrazyl (DPPH(-)) radical scavenging, scavenging activity of 2,2'-azino-bis(3-ethylbenzthiazoline-6-suphonic acid)diammonium (ABTS(+)) radical. The results indicated that BSFP-1 showed strong antioxidant.     

The structure of the low molecular-weight glucans isolated from the siphonous green alga caulerpa simpliciuscula

A β-d-glucan of low molecular weight isolated from the marine alga Caulerpa simpliciuscula has been shown to contain 30 glucose residues. At least 27 of these are β-d-(1→3) linked. There are 1-2β-(1→6) branches per molecule, with a maximum of 4 d-glucose residues per side chain. As normally isolated, this glucan is associated with a soluble (1→4)-α-d-glucan (soluble starch) of the same molecular weight, in the ratio of 3 molecules of β-d-glucan per molecule of α-d-linked glucan.     

草苁蓉根、茎水溶性多糖BRT的结构特征

本文以长白山区珍贵野生药用植物草苁蓉为研究对象 .草苁蓉又名“不老草” ,具有滋补强壮、益寿延年之功及补肾壮阳、润肠止血之效 ,为国家三级重点保护植物[1] .近年的研究发现 ,草苁蓉醇提物不仅可以清除体内的游离基 ,而且还可以显著增强机体的免疫能力 ,同时对草苁蓉化学成分的研究也在逐步深入[2 ] ,但对于草苁蓉多糖的系统研究尚未见报道 .为了更全面地认识和利用草苁蓉这一珍贵的植物资源 ,同时也为探讨多糖的结构与功能的关系 ,本文对草苁蓉根、茎的水溶性多糖ＢＲＴ组分进行了结构测定方面的研究 .1　材料和方法1 1　材料为本研究…     

Purification,structural characterization and antioxidant property of an extracellular polysaccharide from Aspergillus terreus

The marine fungus Aspergillus terreus produces an extracellular polysaccharide, YSS, when grown in potato dextrose-agar medium. YSS was isolated from the fermented liquids using ethanol precipitation, anion-exchange and size-exclusion chromatography. YSS was mainly composed of mannose and galactose in a molar ratio of 7.68:1.00, its average molecular weight was estimated to be about 18.6 kDa. On the basis of chemical and spectroscopic analyses, including one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) spectroscopy, structure of YSS may be represented, at an average, as a backbone of mannan with two types of branches. The mannan backbone is mainly composed of (1→2)-linked α-mannopyranose with small amounts of (1→6)-linked α-mannopyranose residues. The branches consist of terminal β-galactofuranose residues, and disaccharide units of (1→6)-linked α-mannopyranose. The branches are linked to C-6 of (1→2)-linked α-mannopyranose residues of backbone. The antioxidant activity of YSS was evaluated with the scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide and hydroxyl radicals in vitro, and the results indicated that YSS had good antioxidant activity, especially scavenging ability on DPPH radicals. The investigation demonstrated that YSS is a novel branched galactomannan with antioxidant activity, and differs from previously described extracellular polysaccharides.     

Structural features of a polysaccharide from the mucin of water hyacinth

The mucin found in the nodal region of the weed, water hyacinth (Eichhornia crassipes), is a heteropolysaccharide composed of d-xylose, l-galactose and l-arabinose in the mol ratio of 1.3:1.2:1.0. Partial hydrolysis with acid gave four oligosaccharides which were characterized as: d-Xylp-(1 → 3)-l-Ara, l-Galp-(1 -→ 2)-l-Ara, d-Xylp-(1 → 3)-l-Galp-(1 → 2)-l-Ara, and d-Xylp-(1 → 2)-d-Xylp-(1 → 3)-l-Galp-(1 → 2)-l-Ara. These, together with the results of methylation analysis using GC and GC/MS and periodate oxidation, indicated that the trisaccharide repeating unit, → 4)-d-Xylp-(1 → 3)-l-Galp-(1 → 2)-l-Araf-(1 →, constitutes the backbone of the polysaccharide. Further, all the d-xylopyranosyl residues of the backbone are substituted at O-2 and, in addition, one out of seven such residues is also substituted at O-3; the substituents being l-Araf-(1 →, d-Xylp-(1 →, l-Galp-(1 →, d-Xylp-(1 → 3)-l-Araf-(1 →, residues.     

Constitution of sargassan,a sulphated heteropolysaccharide from sargassum linifolium

The behaviour towards periodate of the brown-algal polysaccharide sargassan before and after partial hydrolysis, alkali treatment, and methanolysis has been studied. Evidence is thereby provided that the sargassan backbone is composed of (1→4)-linked β-D-glucuronic acid and β-D-mannose residues. Heteropolymeric, partially sulphated branches are attached to the backbone, and these branches comprise various proportions of(l→4)-linked, β-D-galactose, β-D-galactose 6-sulphate, and β-D-galactose 3,6-disulphate residues, (1→2)-linked α-L-fucose 4-sulphate residues, and (1→3)-linked β-D-xylose residues.     

Studies on the chemical structure and antitumor activity of an exopolysaccharide from Rhizobium sp. N613

The molecular structure of the rhizobium exopolysaccharide (REPS) was analyzed by enzymolysis, periodate oxidation, and Smith degradation, and by IR and NMR spectroscopy. The results indicated that REPS was a β-glucan with a backbone of β-d-(1→4)-linked glucose residues and branches of β-d-(1→6)-linked glucose residues. The branch was attached to the main chain at the 6-O-position. The molar ratio of 1→4 and 1→6 was 2:1. The terminal C3 of the (1→6)-Glc branch had an O-acetyl group. The molecular weight was estimated to be 35 kDa by Sephadex G-100 column chromatography. The antitumor activity of REPS was evaluated in mice bearing sarcoma 180, hepatoma 22, and Ehrlich ascites carcinoma tumor, respectively. At doses of 10-60 mg/kg, it was observed that tumor formation decreased significantly (P <0.01), but the relative spleen and thymus weight, the phagocytic function of monocytes, lymphocyte proliferation, and serum hemolysis antibody increased significantly (P <0.05). Results of these studies demonstrated that the REPS polysaccharide possessed antitumor activity.