Identifications of inhibitors of IgE production by human lymphocytes isolated from ‘Cha Chuukanbohon Nou 6’ tea leaves

BACKGROUND: Tea (Camellia sinensis L.) is consumed all over the world and in especially large quantities in Japan and China, where it has been used not only as a daily beverage but also for medicinal purposes for thousands of years. Tea has been found to exhibit various bioregulatory activities, including antiallergic, anticarcinogenic, antimetastatic, antioxidative, antihypertensive, antihypercholesterolemic, anti‐dental caries and antibacterial effects, and to influence intestinal flora. RESULTS: Cha Chuukanbohon Nou 6 is a tea cultivar improved by the National Institute of Vegetable and Tea Science (NIVTS) in Japan. On comparing chemical constituents of 11 varieties of tea leaves by high‐performance liquid chromatography, we found two new major compounds in Cha Chuukanbohon Nou 6. Nuclear magnetic resonance spectroscopy revealed these compounds to be theogallin and 1,2‐di‐O‐galloyl‐4,6‐O‐(S)‐hexahydroxydiphenoyl‐β‐D ‐glucopyranose. The two were similar in chemical structure to strictinin, an inhibitor of immunoglobulin (Ig) production. Thus their effects on the production of Igs by peripheral blood lymphocytes were tested. Both compounds, like strictinin, inhibited IgE production. CONCLUSION: The results suggest Cha Chuukanbohon Nou 6 to be the basis of an antiallergic beverage. Copyright © 2009 Society of Chemical Industry     

D-葡萄糖五乙酸酯的催化合成研究进展

D-葡萄糖五乙酸酯是非常重要的糖类衍生物,在二氧化碳吸附、医药、精细化工和石油化工等领域用途广泛,关于D-葡萄糖五乙酸酯的合成、产物构型转化与控制是其热点研究方向。本文综述了D-葡萄糖五乙酸酯的催化合成研究进展,主要介绍了均相催化、固体酸催化、酶催化等方法合成D-葡萄糖五乙酸酯的研究情况,重点叙述了吡啶和乙酸钠等碱性催化剂、质子酸和路易斯酸等酸性催化剂、沸石分子筛和杂多酸等固体酸催化剂在D-葡萄糖五乙酸酯合成中的应用情况,指出开发催化活性高、选择性高、构型可调控的催化剂,并将其用于糖类化合物的酯化反应是未来重点研究的方向。     

β-型五氧乙酰化吡喃葡萄糖和半乳糖的微波合成

报道了微波条件下D-葡萄糖和D-半乳糖与乙酸酐在无水醋酸钠催化下的全乙酰化反应。在120℃的微波辐射下,反应进行约10 min即可获得收率分别为88%和78%的1,2,3,4,6-五-O-乙酰基-β-D-吡喃单糖。与传统方法相比较,该法反应条件温和、时间短、收率高、操作简便,为糖类化合物的乙酰化提供了一条绿色合成新途径。     

(4R)-5,6,7,9-四-O-乙酰基-4,8-脱水-4-氯-2,3-二脱氧-D-葡糖壬腈的合成

以乙酰基保护的葡萄糖为原料 ,经氯化 ,溴化反应 ,再与丙烯腈在中压汞灯( 4 50 W)下发生自由基反应 ,高选择性地合成了 ( 4 R) - 5,6,7,9-四 - O-乙酰基 - 4,8-脱水 - 4-氯 - 2 ,3-二脱氧 - D-葡糖壬腈。     

Complex polymer architectures via RAFT polymerization: From fundamental process to extending the scope using click chemistry and nature's building blocks

Reversible addition fragmentation chain transfer (RAFT) polymerization has made a huge impact in macromolecular design. The first block copolymers were described early on, followed by star polymers and then graft polymers. In the last five years, the types of architectures available have become more and more complex. Star and graft polymers now have block structures within their branches, or a range of different branches can be found growing from one core or backbone. Even the synthesis of hyperbranched polymers can be positively influenced by RAFT polymerization, allowing end group control or control over the branching density. The creative combination of RAFT polymerization with other polymerization techniques, such as ATRP or ring-opening polymerization, has extended the array of available architectures. In addition, dendrimers were incorporated either as star core or endfunctionalities. A range of synthetic chemistry pathways have been utilized and combined with polymer chemistry, pathways such as ‘click chemistry’. These combinations have allowed the creation of novel structures. RAFT processes have been combined with natural polymers and other naturally occurring building blocks, including carbohydrates, polysaccharides, cyclodextrins, proteins and peptides. The result from the intertwining of natural and synthetic materials has resulted in the formation of hybrid biopolymers. Following these developments over the last few years, it is remarkable to see that RAFT polymerization has grown from a lab curiosity to a polymerization tool that is now been used with confidence in material design. Most of the described synthetic procedures in the literature in recent years, which incorporate RAFT polymerization, have been undertaken in order to design advanced materials.     

八苄基蔗糖及其水解反应产物的制备

研究了八苄基蔗糖制备的新方法及其水解反应。通过对蔗糖乙酰化保护得到八乙酸蔗糖酯,再经BnCl、KOH反应得到八苄基保护的蔗糖,总收率81%。八苄基蔗糖在乙酸和硫酸溶液中水解得到2,3,4,6-四-O-苄基葡萄糖和1,3,4,6-四-O-苄基果糖,收率分别为29%和25%。产物结构经1HNMR确证。     

水杨醛缩葡萄糖基氨基硫脲希佛碱与Cu(Ⅱ)配合物的研究

合成了一种含硫、氮希佛碱配体——水杨醛缩 N- 氨基 - N′- 2 ,3,4,6- 四 - O- 乙酰基 - β- D- 吡喃葡萄糖基硫脲及其与 Cu2 + 的配合物。并通过元素分析、红外光谱、核磁共振氢谱、摩尔电导率等对配合物结构进行了研究。结果表明两分子配体分别失去了酚羟基上的氢 ,通过 S、 N、 O与一分子 Cu2 + 配位成中性配合物