- Tannins and related polyphenols of melastomataceous plants. III. Nobotanins G, H and I, dimeric hydrolyzable tannins from Heterocentron roseum
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Three new hydrolyzable tannin dimers, nobotanins G (6), H (12) and I (13), have been isolated from the leaves of Heterocentron roseum (Melastomataceae), and their structures were elucidated on the basis of chemical degradations and nuclear magnetic resonance spectral analyses. Nobotanin I (13) is a novel dimer possessing a depsidone-forming valoneoyl group in the molecule. Five known tannins, casuarictin (1), strictinin (2), geraniin (3), and nobotanins B (4) and F (5), were also isolated.
- Yoshida,Haba,Nakata,Okano,Shingu,Okuda
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- TAXIFOLIN APIOSIDE AND DAVURICIIN M1, A HYDROLYSABLE TANNIN FROM ROSA DAVURICA
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Key Word Index - Rosa davurica; Rosaceae; (+)-taxifolin-3-O-β-D-apio-D-furanoside; dihydroflavonol apioside; tannin; davuriciin M1; ellagitannin.Abstract - The structure of a dihydroflavonol glycoside from the roots of Rosa davurica has been characterized as (+)-taxifolin-3-O-β-D-apio-D-furanoside. A new hydrolysable tannin, davuriciin M1, together with three known hydrolysable tannins, have also been isolated.The structure of new tannin was elucidated by spectroscopic and chemical methods.
- Yoshida, Takashi,Jin, Zhe Xiong,Okuda, Takuo
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p. 2177 - 2182
(2007/10/02)
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- Tannins and Related Compounds. Part 3. A New Phenolic Acid, Sanguisorbic Acid Dilactone, and Three New Ellagitannins, Sanguiins H-1, H-2, and H-3, from Sanguisorba officinalis
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A new phenolic acid, sanguisorbic acid dilactone, and three new ellagitannins, sanguiins H-1, H-2, and H-3, have been isolated from the underground parts of Sanguisorba officinalis L. (Rosaceae).On the basis of chemical and spectroscopic evidence, sanguisorbic acid dilactone has been shown to possess a trimeric gallic acid structure and to be a structural isomer of valoneaic acid dilactone.Similarly, sanguiins H-1 and H-2 have been characterized as 1,6-digalloyl-2,3-(4,4',5,5',6,6'-hexahydroxydiphenoyl)glucose and 1-galloyl-2,4-(4,4',5,5',6,6'-hexahydroxydiphenoyl)-3,6-sanguisorboylglucose, respectively.Sanguiin H-3 has been shown mainly by spectroscopic data and analyses of partial hydrolysates to have a novel dimeric structure containing 2,3-(hexahydroxydiphenoyl)glucose and sanguiin H-2 moieties.
- Nonaka, Gen-ichiro,Tanaka, Takashi,Nishioka, Itsuo
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p. 1067 - 1074
(2007/10/02)
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