首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The controlled Smith degradation and limited hydrolysis of glycyrrhizan GA, a representative polysaccharide with remarkable phagocytosis-enhancing activity isolated from the stolon of Glycyrrhiza glabra L. var. glandulifera Reg. et Herd. were carried out. Methylation analyses of the primary and the secondary Smith degradation products and of the limited hydrolysis product indicated that the core structural features of glycyrrhizan GA include a backbone chain composed of beta-1,3-linked D-galactose residues. Three-fifths of the galactose units in the backbone carry side chains composed of beta-1,3- and beta-1,6-linked D-galactosyl residues at position 6. Anti-complementary and alkaline phosphatase-inducing activities of the polysaccharide, periodate oxidation-reduction and the controlled Smith degradation products were investigated, and the controlled Smith degradation product showed significant activity.  相似文献   

2.
The structural features of MVS-I, the major neutral polysaccharide isolated from the seeds of Malva verticillata L., were elucidated by controlled Smith degradation, methylation analysis, partial acid hydrolysis and enzymic degradation studies. It has a backbone chain composed of beta-1,3-linked D-glucose and D-galactose residues having branches composed of alpha-1,5-linked L-arabinosyl beta-1,4-linked D-galactose and of beta-1,4-linked D-galactosyl beta-1,3-linked D-glucose residues at position 6 of a part of D-galactose units as side chains. MVS-I showed remarkable reticuloendothelial system-potentiating activity in a carbon clearance test.  相似文献   

3.
The controlled Smith degradation of MVS-VI, the major acidic polysaccharide having remarkable anti-complementary activity isolated from the seeds of Malva verticillata L., was performed. Methylation analysis of both the primary and the secondary Smith degradation products indicated that the core structural features of MVS-VI include a backbone chain composed of beta-1,3-linked D-galactose residues. The majority of galactose units in the backbone carry side chains composed of beta-1,3- and beta-1,6-linked D-galactosyl residues at position 6. The controlled Smith degradation products showed considerable anti-complementary activity.  相似文献   

4.
The controlled Smith degradation of ukonan A, a phagocytosis-activating polysaccharide isolated from the rhizome of Curcuma longa L., was performed. The reticuloendothelial system-potentiating, anti-complementary and alkaline phosphatase-inducing activities of ukonan A and its degradation products were investigated. Methylation analyses of both the primary and the secondary Smith degradation products indicated that the core structural features of ukonan A include a backbone chain mainly composed of beta-1,3-linked D-galactose, beta-1,4-linked D-xylose and alpha-1,2-linked L-rhamnose residues. All of the galactose units in the backbone carry side chains composed of alpha-L-arabino-beta-D-galactosyl or beta-D-galactosyl residues at position 6. Ukonan A has a remarkable effect on each of the three kinds of immunological activities. Periodate oxidation caused pronounced decrease or disappearance of the activities, but the controlled Smith degradation product having the core structure of polysaccharide showed considerable restoration of these activities.  相似文献   

5.
An acidic polysaccharide, designated as cnidirhan AG, was isolated from the rhizomes of Cnidium officinale Makino. It was homogeneous on electrophoresis and gel chromatography, and its molecular mass was estimated to be 5.1 x 10(4). It showed pronounced reticuloendothelial system-potentiating activity in a carbon clearance test, and had a remarkable effect on both anti-complementary and alkaline phosphatase-inducing activities. It is composed of L-arabinose: D-galactose: D-glucuronic acid in the molar ratio of 2:6:1, in addition to small amounts of O-acetyl groups. Methylation analysis, carbon-13 nuclear magnetic resonance, controlled Smith degradation and limited acid hydrolysis indicated that the core structural features of cnidirhan AG include a backbone chain composed of beta-1,3-linked D-galactose residues. Some of the galactose units in the backbone carry beta-D-galactosyl side chains at position 6. Both alpha-L-arabinosyl arabinose side chains and terminal beta-D-glucuronic acid residues are linked to the core galactan units.  相似文献   

6.
The major acidic polysaccharide, named saposhnikovan A, was isolated from the roots and rhizomes of Saposhnikovia divaricata. It showed remarkable reticuloendothelial system-potentiating activity in a carbon clearance test. It is composed of L-arabinose: D-galactose: D-galacturonic acid in the molar ratio of 6:15:10, and its molecular weight was estimated to be 54000. About 35% of the D-galacturonic acid residues exist as the methyl esters. Methylation analysis, 13C-nuclear magnetic resonance, and controlled Smith degradation studies indicated that the polysaccharide has the alpha-1----4-linked D-galacturonan backbone bearing alpha-1----5-linked L-arabino-beta-3,6-branched D-galactan side chains.  相似文献   

7.
The structure of an anti-diabetic polysaccharide (TAP) obtained from the fruiting bodies of Tremella aurantia was investigated by methylation analysis, Smith degradation, partial acid hydrolysis, 13C-NMR spectrometry, and enzymatic digestion. The results suggested that TAP was composed of (1-->3)-linked alpha-D-mannopyranosyl residues as a backbone, some of which were substituted at position 2 with (1-->3)-linked beta-D-xylopyranose side chains and with beta-D-glucopyransyluronic acid at position 4 linked to terminal alpha-D-mannopyranose.  相似文献   

8.
Two polysaccharides, called glycyrrhizans UA and UB, were isolated from the root of Glycyrrhiza uralensis Fischer. They were homogeneous on electrophoresis and gel chromatography, and showed reticuloendothelial system-potentiating activity in a carbon clearance test. Glycyrrhizan UA is composed of L-arabinose: D-galactose: L-rhamnose: D-galacturonic acid in the molar ratio of 20:14:1:3, and glycyrrhizan UB is composed of L-arabinose: D-galactose: D-glucose: L-rhamnose: D-galacturonic acid in the molar ratio of 12:10:1:10:20, in addition to small amounts of O-acetyl groups and peptide moiety, respectively. About 10% (glycyrrhizan UA) and 35% (glycyrrhizan UB) of the D-galacturonic acid residues exist as the methyl esters. Methylation analysis, carbon-13 nuclear magnetic resonance and periodate oxidation studies indicated their structural features.  相似文献   

9.
从山茱萸中提取出水溶性粗多糖, 经柱色谱分离纯化得到一种酸性多糖组分FCP5-A. 采用高效凝胶渗透色谱法(HPGPC)测定其为均一性多糖, 平均分子量为8.7×104. 经IR、GC、部分酸水解、13C NMR及甲基化分析等方法对该多糖的化学结构进行了表征. 结果表明, 该多糖由鼠李糖、阿拉伯糖、半乳糖及半乳糖醛酸组成, 其摩尔比为1∶5.7∶0.6∶1.2. FCP5-A为多分支结构, 由-2)Rha(1-及-4)GalA(1-构成主链, 在鼠李糖的4位存在分支; 支链主要由高度分支的阿拉伯糖构成, 此外还存在-3)Gal(1-; 末端残基为Ara(1-及Gal(1-. 结果提示, FCP5-A为一种新的山茱萸酸性分支多糖.  相似文献   

10.
An acidic polysaccharide, named saposhnikovan C, was isolated from the roots and rhizomes of Saposhnikovia divaricata Schischk. It was homogeneous as judged by electrophoresis and gel chromatography, and showed remarkable reticuloendothelial system-potentiating activity in a carbon clearance test. It is composed of D-galacturonic acid:L-rhamnose:L-arabinose:D-galactose in a molar ratio of 27:7:8:8, and its molecular mass was estimated to be 132000. About 30% of the D-galacturonic acid residues exist as the methyl esters. O-Acetyl groups were identified, and the content amounted to 3.3%. Methylation analysis, carbon-13 nuclear magnetic resonance, and controlled Smith degradation studies indicated the structural features. It has a pectin-like rhamnogalacturonan backbone with branched arabinan and galactan side chains.  相似文献   

11.
A neutral polysaccharide, named ukonan D, was isolated from the rhizome of Curcuma longa L. It produced a single band on electrophoresis and a single peak on gel chromatography, and its molecular mass was estimated to be 28,000. It showed remarkable reticuloendothelial system-potentiating activity in a carbon clearance test. Ukonan D is composed of L-arabinose: D-galactose: D-glucose: D-mannose in the molar ratio of 1:1:12:0.2, in addition to small amounts of peptide moiety. Methylation analysis, carbon-13 nuclear magnetic resonance and enzymic degradation studies indicated that its structural features include mainly both alpha-1,5-linked L-arabino-beta-3,6-branched D-galactan type and alpha-4,6-branched D-glucan type structural units. The influence of degradation with alpha-amylase followed by the elimination of glucan side chains on its immunological activity was discussed.  相似文献   

12.
Structural Features of a Polysaccharide from Centella asiatica   总被引:3,自引:0,他引:3  
Centella asiatica has been used as remedy for sodation, stabilization and against lepra, anabrosis1 in the oriental countries. The low-molecular-weight constituents in Centella asiatica have been investigated1. However, no polysaccharides have been reported. 1BI was the first polysaccharide isolated from C. asiatica, which had immunostimulating activity in vitro. In present study, we report the structural features of 1BI. Experimental Extraction, isolation and purification Dried C.…  相似文献   

13.
Five kinds of chemically modified products were prepared from Plantago-mucilage A, the representative mucous polysaccharide isolated from the seed of Plantago asiatica L., and their reticuloendothelial system-potentiating and alkaline phosphatase-inducing activities have been investigated. Both activities were markedly enhanced when the mucilage was de-O-acetylated. The products obtained by periodate oxidation, controlled Smith degradation, and partial acid hydrolysis under the two conditions were not effective. Structural features of the partial hydrolyzates were elucidated, and it was shown that these products lost all O-acetyl groups, all xylose branches and many hexuronosyl arabinose side chains.  相似文献   

14.
From rhizomes of Panax japonicus (Araliaceae), two polysaccharides named tochibanan-A and -B, which show reticuloendothelial-potentiating activity in the carbon clearance test in mice, were isolated. The structure of tochibanan-A (molecular mass: 23,000) was elucidated as a linear beta-1,4-D-galactan. Tochibanan-B (molecular mass: 40,000) consists of D-galactose (87.1%), L-arabinose, D-glucose and D-galacturonic acid and has a beta-D-(1----4)-linked galactopyranosyl backbone possessing GalA-(1----6)-Gal, Ara-(1----5)-Ara, Gal, and Glc side chains. The structure around the branching points and the repeating unit were investigated and a possible structure of tochibanan-B is proposed.  相似文献   

15.
The gum exudate from Anacardium occidentale contains galactose (61 %), arabinose (14 %), rhamnose (7 %), glucose (8 %) and glucuronic acid (5 %) in addition to small amounts (<2 %) of each of mannose, xylose and 4-0 methylglucuronic acid. Contrary to earlier findings, the main aldobiuronic acid present is 6-O-(β-D-glucopyranosyluronic acid)-D-galactose; smaller amounts of the 4-O-methyl analogue are also present. Mild acid hydrolysis showed only two galactobioses, 3-O-β-D-galactopyranosyl-D-galactose (major
component) and 6-O-β-D-galactopyranosyl-D-galactose (minor component). Degraded gum A, prepared by controlled acid hydrolysis, contained galactose, glucose, and uronic acid. A Smith-degradation of degraded gum A gave degraded gum B, which contained only galactose. Sequential Smith-degradations of Anacardium occidentale gum, and methylation analyses of the gum and of its degradation products indicated a highly-branched galactan framework consisting of chains of β-(1–3)-linked D-galactose residues branched and interspersed with β-(1–6) linkages. Arabinose is present as end-groups or in short (1–2)-linked chains up to five units long. Glucose, rhamnose, mannose xylose, and uronic acid are all present as end-groups.  相似文献   

16.
IntroductionPhellinus igniariusbelongs to the phylum Basidio-mycota and is widely distributed in China, Japan, Aus-tralia, Philippines, and North America. The myceliumofP igniariusis perennial and grows on the stock oflatifoliate trees, such as robur, bir…  相似文献   

17.
A neutral polysaccharide, named glycyrrhizan UC, was isolated from the root of Glycyrrhiza uralensis Fischer. It was homogeneous on electrophoresis and gel chromatography, and its molecular mass was estimated to be 69,000. Glycyrrhizan UC is composed of L-arabinose:D-galactose:D-glucose:L-rhamnose in the molar ratio of 10:30 27:1. Methylation analysis, carbon-13 nuclear magnetic resonance and periodate oxidation studies indicated its structural feature as an arabino-3,6-galacto-glucan type polysaccharide.  相似文献   

18.
生漆多糖的分离与结构研究   总被引:7,自引:0,他引:7  
生漆用丙酮提取不溶解物,除去其水不溶部分、依次进行732阳离子交换树脂和SephadexG-100柱层析、得到白色粉末漆多糖.分子量12.5×10 ̄4.其组成为D-半乳糖、D-葡萄糖醛酸、L-阿拉伯糖和L-鼠李糖.摩尔比为7.7:1.8:0.4:0.1.经羧基还原、甲基化反应、高碘酸盐氧化、Smith降解和GC-MS、IR、 ̄1H-NMR、 ̄13C-NMR分析、结果表明,漆多糖为多分支结构、分子主链由β(1→3)D-半乳糖基构成.部分半乳糖基C_6位有支链,另有部分半乳糖基以(1→6)键连接,其中β(1→3)与β(1→6)甙键糖基组成比为1.83:1.分子的支链由葡萄糖醛酸基、阿拉伯糖基、鼠李糖基组成,并且葡萄糖醛酸基构成分子的末端基.  相似文献   

19.
Xylan is a barrier to enzymatic hydrolysis of plant cell walls. It is well accepted that the xylan layer needs to be removed to efficiently hydrolyze cellulose; consequently, pretreatment conditions are (in part) optimized for maximal xylan depolymerization or displacement. Xylan consists of a long chain of β-1,4-linked xylose units substituted with arabinose (typically α-1,3-linked in grasses) and glucuronic acid (α-1,2-linked). Xylan has been proposed to have a structural function in plants and therefore may play a role in determining biomass reactivity to pretreatment. It has been proposed that substitutions along xylan chains are not random and, based upon studies of pericarp xylan, are organized in domains that have specific structural functions. Analysis of intact xylan is problematic because of its chain length (> degree of polymerization (d.p.) 100) and heterogeneous side groups. Traditionally, enzymatic end-point products have been characterized due to the limited products generated. Analysis of resultant arabino-xylo-oligosaccharides by mass spectrometry is complicated by the isobaric pentose sugars that primarily compose xylan. In this report, the variation in pentose ring structures was exploited for selective oxidation of the arabinofuranose primary alcohols followed by acid depolymerization to provide oligosaccharides with modified arabinose branches intact. Switchgrass samples were analyzed by hydrophilic interaction chromatography (HILIC)-liquid chromatography (LC)-mass spectrometry/mass spectrometry (MSMS) and off-line nanospray MS to demonstrate the utility of this chemistry for determination of primary hydroxyl groups on oligosaccharide structures, with potential applications for determining the sequence of arabino-xylo-oligosaccharides present in plant cell wall material.  相似文献   

20.
通过三甲基碘硅烷与聚二(2-甲氧基乙氧基)膦腈侧链上的醚键反应后水解得到侧链含部分羟基的聚膦腈,然后利用聚膦腈的侧链羟基在异辛酸亚锡催化作用下,引发己内酯单体开环聚合制备了聚膦腈-g-聚己内酯共聚物.该共聚物中聚己内酯链段的接枝率和侧链长度可通过改变三甲基碘硅烷和己内酯单体的投料来控制.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号