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The Chemical modifications of condensed tannin by base-catalyzed reactions.

通过碱催化反应对缩合单宁进行化学改性。

基本信息

批准号：
07660218
负责人：
ABE Isao
金额：
$ 1.47万
依托单位：
Mie University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07660218/
关键词：
Condensed tannin Vanillin-HCl method Phosphomolybdic acid method Pheny-Nucleous Exchange method Base-catalyzed modification of condensed tannin Nucleophilicity of tannins Differential scanning caloimetry (DSC)GTase inhibitory activity タンニ

项目摘要

Developments of useful usege for the condensed tannins are the indispensable for convert the useless barks into valuable resources. However, effective usages of the tannins having the polyphenolic characteristics have not been realized.This study was undertaken to make the condensed tannins more uniform and flexible polyphenol oligomers by the use of base-catalyzed reaction, and the effects of the denaturing treatment by alkali on the of nucleophilicity and GTase inhibitory activity of tannins were discussed.The results obtained were summarized below. 1) Preparations and structural analysis of condensed tannin. Appropriate techniques for preparing the synthesized tannins were developed and their mechanism was elucidated. Furthermore, the composite technique for charicterize the tannins were proposed by the use of vanillin-HCl, phosphomolybdic acid and pheny-nucleous exchange methods. 2) The chemical modification of condensed tannin by the base-catalyzed reactions. By the treatment with … More alkaline solutions, the tannin molecule was estimated to convert more flexible but B-ring of the polyphenols was destroyed as well as A-ring, even if the mild conditions were emplyed. 3) DSC for analysis of addition-, condensation- and curing-reactions. Through the examinations on the reaction with HCHO_<aq>., it was concluded that the condensed tannin have to regard as the novolak type materials. So the proper technique for analysis ot the complex reaction, that is addition, condensation and curing, had to be developed. For this purpose, DSC technique using high pressured cell was emplyed in the HCHO/H_2O system and the exothermic heat depended on the enthalpy changes during of the reaction with HCHO were recognized to nicely correlate with chemical change during the reactions. 4) Characterization of alkaline-denatured tannins by DSC.It was confirmed by the DSC examinations that the denaturing treatment by the base-catalyzed reaction was the one of the procedue to improve the reactivity of the tannin. 5) GTase inhibitory activity of alkaline-denatured tannins. Bark tannins exhibit strong GTase inhibitory activity, but alkaline treatment by the severe conditions caused for their specificity decreasing. These behavior suggests that the vicinal hydroxyl pattern of the constituted phenyl-nuclei affects the specificity strongly. Less

开发利用缩合单宁是将无用树皮转化为宝贵资源的必要条件。本研究利用碱催化反应制备缩合单宁，并探讨了碱变性处理对单宁亲核性和GTase抑制活性的影响。1)缩合单宁的制备与结构分析。研究了合成单宁的适宜工艺条件，并对其作用机理进行了探讨。并提出了香草醛-盐酸法、磷钼酸法和苯环交换法对单宁的复合改性工艺。2)缩合单宁的碱催化化学改性。通过用 ...更多信息在碱性条件下，单宁分子的弹性增强，但多酚的B环和A环均被破坏。3)DSC用于分析加成、缩合和固化反应。通过与甲醛反应的考察<aq>，认为缩合单宁应作为酚醛树脂类原料。因此，必须发展合适的技术来分析复杂的反应，即加成、缩合和固化反应。本文采用高压差示扫描量热法（DSC）对甲醛/水体系进行了研究，发现甲醛与水反应的放热与反应过程中的化学变化有很好的相关性。4)碱变性单宁的DSC表征通过DSC研究，证实了碱催化变性处理是提高单宁反应活性的方法之一。5)碱变性单宁的GTase抑制活性。树皮单宁具有较强的GTase抑制活性，但经碱处理后其特异性降低。这些行为表明，邻位羟基模式的苯基构成的核强烈影响的特异性。少