阿拉伯糖

We investigated constituent of triterpenoid saponins ofAlbizzia, two new compounds together with two known compounds were isolated from Albizzia julibrissin Durazz. by using column chromatography (macroreticular resin, silica gel, Sephadex gel, reverse phase silica gel),preparative HPLC methods et al.On the basis of spectroscopic analysis, including IR,ESI-MS,~1H-NMR,~(13)C-NMR,HMBC,HMQC,~1H-~1HCOSY and chemical methods, the structure of two new compounds were identified as 3 - O -[β-D-xylopyranosyl(1→2)-β-D-fucopyranosyl (1→6)-β- D -2- deoxy - 2 - acetoamidoglucopyranosyl] -21-O-[(6S)-2- trans- 2,6-dimethyl - 6 - O-β- D - quinovopyranosyl -2,7- octadienoyl] - acacic acid- 28 - O-β-D-glucopyranosyl(1→3)[α-L-arabinofuranosyl(1→4)]-α-L-rhamnopyranosyl(1→2)-β-D-glucopyranoside acacic acid 3- O -β- D- glucopyranosy(1→3)-β- D- fucopyranosl(1→6) [β-D- xylopyranosyl (1→2)]-β-D-glucopyranoside ;two known compounds were acacic acid lactone 3- O -β-D- xylopyranosyl-(1→2)-β-D-fucopyranosl (1→6)- 2-deoxy -2 -acetoamido -β-D- glucopyranoside ; acacic acid lactone 3- O-β-D-xylopyranosyl(1→2)-α-L- arabinopyranosl (1→6)- 2- deoxy - 2- acetoamido -β-D-glucopyranoside . The study lays chemical foundation and chemical reference substance for enhancing quality standard of Albizzia julibrissin Durazz.

本研究论文在综述国内外对合欢属Albizzia三萜皂苷化学成分和药理作用研究进展的基础上，利用传统植化分离手段和现代分离技术，包括大孔树脂、硅胶、葡聚糖凝胶、反相硅胶等柱色谱，制备高效液相色谱法等技术从中药合欢皮中分离得到了4个化合物，其中，2个新化合物和2个己知化合物，并进一步通过现代分析技术IR，ESI-MS，~1H-NMR，~(13C-NMR，HMBC，HMQC，~1H-~1HCOSY等和化学方法鉴定了2个新化合物的结构分别是：3-O-[β-D-吡喃木糖基(1→2)-β-D-吡喃夫糖基(1→6)-β-D-2-去氧-2-乙酰氨基吡喃葡萄糖基]-21-O-[(6S)-2-反式-2，6-二甲基-6-O-β-D-吡喃鸡纳糖基-2，7-辛二烯酸基]-金合欢酸-28-O-α-L-呋喃阿拉伯糖基(1→4)[β-D-吡喃葡萄糖基(1→3)]-α-L-吡喃鼠李糖基(1→2)-β-D-吡喃葡萄糖苷，金合欢酸3-O-β-D-吡喃葡萄糖基(1→3)-β-D-吡喃夫糖基(1→6)[β-D-吡喃木糖基(1→2)]-β-D-吡喃葡萄糖苷；2个已知化合物结构分别是：金和欢酸内酯3-O-β-D-吡喃木糖基(1→2)-β-D-吡喃夫糖基(1→6)-β-D-2-去氧-2-乙酰氨基吡喃葡萄糖苷，金和欢酸内酯3-O-β-D-吡喃木糖基(1→2)-α-L-吡喃阿拉伯糖基(1→6)-β-D-2-去氧-2-乙酰氨基吡喃葡萄糖苷。

Glycosides of arabinose distribute widely in nature and most of them is biologically active.

阿拉伯糖苷类化合物广泛存在于自然界中，是许多药物的有效成分，具有生物活性，如盾叶鬼臼素A，具有强烈的抗肿瘤活性，阿拉伯糖氧苷是阿拉伯呋喃糖酶的重要底物。

Xylanases are a group of enzymes that break down xylans into xylooligosaccharides, xylose and arabinose, and thus are of high potential for use in feed, paper making and food industry.

木聚糖酶以内切方式作用于木聚糖分子中β-1，4-木糖苷键，可将木聚糖水解为木二糖和木二糖以上的低聚木糖，以及少量木糖和阿拉伯糖，在饲料、造纸和食品等行业具有广阔的应用前景。

But in the process of ion exchange, xylose molecular is easily converted into arabinose because of catalytic isomerization, which results in the decrease of its purity and difficulty of crystal.

木糖是一种在化工、食品等领域有着广泛用途的五碳糖，工业生产是用稀强酸将玉米芯中含有的大量多缩戊糖分解为单个的木糖分子，然后通过离子交换除盐、脱色，精制提取，但在强碱离子交换柱中，木糖分子容易被部分催化异构转化为阿拉伯糖，使得木糖纯度下降，结晶困难。

Wheat neoside A is apigenin 6-C-galactoside-8-C-(2'-sinapic acid acyl) arabinfuranoside; wheat neoside B is apigenin 6-C-(2'-sinapic acid acyl) arabinfuranoside-8-C- galactoside.

小麦新苷A为芹菜素-6-C-半乳糖苷-8-C-(2'-芥子酸酰基)阿拉伯糖苷；小麦新苷B为芹菜素-6-C-(2'-芥子酸酰基)阿拉伯糖苷-8-C-半乳糖苷。

RESULTS:Six flavonoids 6-C-glycopyranosyl-8-C-glycopyranosyl apigenin(1),6-C-arabinosyl-8-C-glycopyranosyl apigenin(2),6-C-glycopyranosyl-8-C-arabinosyl apigenin(3),6-C-glycopyranosyl-8-C-xyloeyl apigenin(4),6-C-glycopyranosyl luteolin(5),luteolin(6),one chromone isobiflorin(7),and one lignanoid-isolariciresinol(8),were isolated from the n-BuOH fraction of this plant,respectively.

结果：从毛鸡骨草地上部分的正丁醇部位分离并鉴定了8个化合物，黄酮类化合物：芹菜素-6-C-葡萄糖-8-C-葡萄糖苷（1），芹菜素-6-C-阿拉伯糖-8-C-葡萄糖苷（2），芹菜素-6-C-葡萄糖-8-C-阿拉伯糖苷（3），芹菜素-6-C-葡萄糖-8-C-木糖苷（4），木犀草素-6-C-葡萄糖苷（5），木犀草素（6）；色原酮类化合物：异双花母草素（7）；木脂素类化合物：-异落叶松树脂醇（8）。

By means of GPC,IR,GC-MS,~(13)CNMR,~1HNMR,Methylation analysisetc,structural properties of PST-1 were identified as follows:The Mwof PST-1 was 3.44×10~6 Da and its optical rotation was _D~(20)=+0.110°(c0.1, H_2O); PST-1 constituted 8 simple sugars and the molar ratio was 2,4-Dimethoxy-Mannose:Rhamnose:Ara-binose:Xylose:Galactose:D-Galacturonic acid:Mannose:D-glucuronic acid=2%:5%:24%:9%:3%:1%:46%:10%;The chief bone of PST-1 was 1,3,6-linked-β-D-Man residue and the side chains contained Furanoid and Pyranoid residues.

结合GPC、旋光度测定、IR、GC-MS、~(13)CNMR、~1HNMR、高碘酸氧化法、Smith降解以及甲基化方法等分析测试方法，得到PST-1的单糖组成及结构表征，实验结果如下：红豆杉多糖PST-1是重均分子量为3.44×10~6 Da的支链多糖，旋光度为20D=+0.110~0(c0.1，H_2O)；PST-1单糖组成为：2，4-Dimethoxy-Mannose：Rhamnose：Arabinose：Xylose：Galactose：D-Galacturonic acid：Mannose：D-glucuronic acid=2％：5％：24％：9％：3％：1％：46％：10％；PST-1的骨架结构为：具有1，3，6-连接的β-D-甘露糖残基骨架，侧链分枝包括非还原末端的呋喃型α-L-阿拉伯糖残基、吡喃型α-L-阿拉伯糖残基、β-D-木糖残基、β-D-甘露糖残基、2，4-二氧甲基-β-D-甘露糖残基和α-D-葡萄糖醛酸残基；侧链的糖残基也可能存在2，5-二氧-取代呋喃型α-L-阿拉伯糖基、3-氧-取代的β-D-木糖残基、6-氧-取代的α-D-半乳糖醛酸残基、6-氧-取代的α-D-半乳糖残基、4-氧-取代的α-D-葡萄糖醛酸残基和2-氧-取代的α-L-鼠李糖残基，同时后者也可能穿插在主链上。

Main monosaccharide were Arabinose, Xylose, Mannose, Glucose and Galactose. The structure of SPG was studied by IR and alkaline β-elimination reaction. It was found that:(1) SFG contains α-glucosidic bonds;(2) the type of the glucosidic bonds was pyranose,(3) the protein was covalently linked with the carbohydrate by 0-glycosyl linkage.

气相色谱分析表明甘薯糖蛋白中糖链部分含有鼠李糖、阿拉伯糖、甘露糖、葡萄糖、半乳糖；红外光谱和汗消去反应表明：甘薯糖蛋白中含有α-糖苷键，糖苷键类型主要为吡喃型；糖与蛋白的肽链之间的连接点类型是O-糖肽键。

L-arabinose isomerase can isomerize L-arabinose and D-galactose into L-ribulose and D-tagatose, respectively, which is currently the most effective biological catalyst for D-tagatose production.

L-阿拉伯糖异构酶能分别催化L-阿拉伯糖和D-半乳糖异构为L-核酮糖和D-塔格糖，它是目前生物法生产新型功能性因子D-塔格糖最为有效的酶。

Ethambutol is a first-line drug used for antituberculosis therapy. It is often used in combination with isoniazid, rifampin, pyrazinamide, and streptomycin. The action of EMB in antituberculosis mechanism is the destruction of cell wall of tubercle bacilli via binding the target molecule -- arabinosyl transferases. These enzymes are involved in the polymerization of the cell wall arabinan. Inhibition of arabinan synthesis by EMB results in the accumulation of mycolic acids, leading to cell death.The EMB-resistance of MTB is involved with the mutation of emb operon or the over expression of emb operon.

乙胺丁醇是和异烟肼、利福平、链霉素、吡嗪酰胺联合治疗结核病的一线抗结核药物，EMB对结核分枝杆菌的作用机制与分枝杆菌胞壁结构破坏有关，主要作用于靶分子阿拉伯糖基转移酶，抑制了阿拉伯糖基聚合入阿拉伯半乳聚糖，从而影响细胞壁分枝菌酸-阿拉伯半乳聚糖-肽聚糖复合物的形成，导致菌细胞的死亡。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。