| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
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
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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
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