| Budget Amount *help |
¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1985: ¥4,700,000 (Direct Cost: ¥4,700,000)
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| Research Abstract |
Chemical examinations of polyphenols, especially of tannins, in about 15 crude drugs (Cassia bark, rhubarb, etc.) and about 20 plants such as those of the genera Quercus and Salix have led to the isolation and structural elucidation of about 130 new compounds. The results of the experiments are summarized according to their structural features and are described as follows.
1. Hydrolyzable Tannins (1) Gallotannins: Among about 20 new compounds, the isolation of those with a core of shikimic acid, scyllo-quercitol and triterpenoid alcohol is of great significance from the viewpoint of plant physiology. (2) Ellagitannins: Of about 20 new compounds isolated, sanguiin H-11, which contains 4 glucose cores in its molecule, has the highest-molecular-weight among the hydrolyzable tannins so for found, while the isolation of elaeocarpusin indicates that ascorbic acid plays an important role in the metabolism of galloyl groups. In addition, the isolation of many of the new compounds of this class
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has chemical and plant physiological significnace.
2. Condensed Tannins (1) Simple Condensed Tannins: About 50 new compounds including monomers-hexamers have been isolated, and chemistry of the compounds of this group has been almost entirely elucidated. (2) Complex Condensed Tannins: Together with the isolation and structure elucidation of about 10 new compounds which possess a cafferic acid or a chalcan- <beta> -ol moiety in the molecule, the tannins of this class have been demonstrated to be distributed widely in the plant kingdom.
3. New-type Tannins: A new class of about 10 tannins which contain both hydrolyzable and flavan-3-ol moieties in the molecule, has been isolated from Fagaceous plants.
4. Others: The isolation and structure determination of about 20 new tannin-related compounds including red pigments of black tea and phenol gallates of rhubarbs has provided important information about the mode of oxidative coupling of flavan-3-ols in a tea fermentation process and about the metabolism of polyphenols in plant tissues. Less
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