Highly Oxidized Ellagitannins of Carpinus japonica and Their Oxidation–Reduction Disproportionation
| Autor: | Yosuke Matsuo, Yoshinori Saito, Manami Era, Kosuke Aritake, Takashi Tanaka, Gen-Ichiro Nonaka, Daisetsu Kojima, Kengo Shimizu |
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| Rok vydání: | 2020 |
| Předmět: |
Pharmacology
chemistry.chemical_classification biology 010405 organic chemistry Organic Chemistry Pharmaceutical Science Disproportionation Buffer solution Metabolism Ascorbic acid biology.organism_classification 01 natural sciences Medicinal chemistry Redox 0104 chemical sciences Analytical Chemistry 010404 medicinal & biomolecular chemistry chemistry.chemical_compound Complementary and alternative medicine chemistry Ellagitannin Carpinus japonica Drug Discovery Molecular Medicine Oxidative coupling of methane |
| Zdroj: | Journal of Natural Products. 83:3424-3434 |
| ISSN: | 1520-6025 0163-3864 |
| Popis: | In the research on ellagitannin metabolism, two unique dehydroellagitannins, carpinins E (1) and F (2), bearing dehydrohexahydroxydiphenoyl (DHHDP) and hydrated biscyclohexenetrione dicarboxyl ester (HBCHT) groups, were isolated from young leaves of Carpinus japonica. Upon heating in H2O or treatment with pH 6 buffer at room temperature, 1 and 2 afforded the reduction product 3, isocarpinin A, with an (R)-hexahydroxydiphenoyl (HHDP) group, suggesting the occurrence of redox disproportionation of the (S)-DHHDP group. This was supported by the increase in production of 3 in the pH 6 buffer solution by coexistence of epigallocatechin-3-O-gallate (15), accompanied by oxidation of 15. In contrast, treatment of 1 and 2 with ascorbic acid yielded 4, carpinin A, with an (S)-HHDP group. Upon heating with ascorbic acid, the HBCHT group was also reduced to an (S)-HHDP group, and 2 was converted to 2,3;4,6-bis(S)-HHDP glucose. In leaves of C. japonica, the tannins 1 and 2 are dominant in young spring leaves, but compounds 3 and 4 become the major components of tannins in mature leaves. These results suggest that, in ellagitannin biosynthesis, oxidative coupling of the two galloyl groups first generates a DHHDP group, and subsequent reduction of DHHDP esters produces HHDP esters. |
| Databáze: | OpenAIRE |
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