476-66-4Relevant articles and documents
Stability and oxidation products of hydrolysable tannins in basic conditions detected by HPLC/DAD-ESI/QTOF/MS
Tuominen, Anu,Sundman, Terhi
, p. 424 - 435 (2013)
Introduction Hydrolysable tannins occur in plants that are used for food or medicine by humans or herbivores. Basic conditions can alter the structures of tannins, that is, the oxidation of phenolic groups can lead to the formation of toxic quinones. Previously, these labile quinones and other oxidation products have been studied with colorimetric or electron paramagnetic resonance methods, which give limited information about products. Objective To study the stability and oxidation products of hydrolysable tannins in basic conditions using HPLC with a diode-array detector (DAD) combined with electrospray ionisation (ESI) and quadrupole time-of-flight (QTOF) MS. Methods Three galloyl glucoses, four galloyl derivatives with different polyols and three ellagitannins were purified from plants. The incubation reactions of tannins were monitored by HPLC/DAD at five pH values and in reduced oxygen conditions. Reaction products were identified based on UV spectra and mass spectral fragmentation obtained with the high-resolution HPLC/DAD-ESI/QTOF/MS. The use of a base-resistant HPLC column enabled injections without the sample pre-treatment and thus detection of short-lived products. Results Hydrolysable tannins were unstable in basic conditions and half-lives were mostly less than 10 min at pH 10. Degradation rates were faster at pH 11 but slower at milder pH. The HPLC analyses revealed that various products were formed and identified to be the result of hydrolysis, deprotonation and oxidation. Interestingly, the main hydrolysis product was ellagic acid; it was also formed from galloyl glucoses that do not contain oxidatively coupled galloyl groups in their initial structures. Conclusion HPLD/DAD-ESI/QTOF/MS was an efficient method for the identification of polyphenol oxidation products and showed how different pH conditions determine the fate of hydrolysable tannins. Copyright
The biomimetic synthesis of balsaminone A and ellagic acid via oxidative dimerization
Daley, Sharna-Kay,Downer-Riley, Nadale
, p. 2026 - 2031 (2020)
The application of oxidative dimerization for the biomimetic synthesis of balsaminone A and ellagic acid is described. Balsaminone A is synthesized via the oxidative dimerization of 1,2,4-trimethoxynaphthalene under anhydrous conditions using CAN, PIDA in BF3·OEt2 or PIFA in BF3·OEt2 in 7–8% yields over 3 steps. Ellagic acid is synthesized from its biosynthetic precursor gallic acid, in 83% yield over 2 steps.
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Nierenstein,Spiers,Hatcher
, p. 846 (1925)
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Rhoipteleanins A and E, Dimeric Ellagitannins formed by Intermolecular C-C Oxidative Coupling from Rhoiptelea chiliantha
Jiang, Zhi-Hong,Tanaka, Takashi,Kouno, Isao
, p. 1467 - 1468 (1995)
The first dimeric ellagitannins, rhoipteleanins A and E, generated biogenetically by intermoleuclar C-C oxidative coupling, are isolated from the fruits of Rhoiptelea chiliantha and structurally elucidated on the basis of spectroscopic and chemical evidence.
Ellagic acid formation from galloylglucoses by a crude enzyme of Cornus capitata adventitious roots
Tanaka, Norie,Shimomura, Koichiro,Ishimaru, Kanji
, p. 1869 - 1871 (2001)
The aqueous extract of acetone powder, which had been prepared from Cornus capitata 'Mountain Moon' adventitious roots, cultured in MS medium with a high concentration of Cu2+ (10 μM), showed strong oxidative activity toward galloylglucoses. A compound formed from galloyglucoses, such as 1,2,3,4,6-penta-O-galloylβ-D-glucose and tannic acid, by the reaction with the crude enzyme solution of the adventitious roots was isolated and characterized as ellagic acid by spectrometric analyses.
Nierenstein
, p. 912 (1931)
Seshadri,Vasishta
, p. 317,321, 322 (1965)
Ellagitannins and oligomeric proanthocyanidins of three polygonaceous plants
Huang, Yong-Lin,Jiang, Zhi-Hong,Kitaoka, Masako,Li, Dian-Peng,Li, Yun-Qiu,Matsuo, Yosuke,Nonaka, Gen-Ichiro,Saito, Yoshinori,Takayoshi, Juri,Tanaka, Takashi,Wang, Ya-Feng
, (2021/06/28)
The aim of this study was to characterize hydrolyzable tannins in Polygonaceous plants, as only a few plants have previously been reported to contain ellagitannins. From Persicaria chinensis, a new hydrolyzable tannin called persicarianin was isolated and characterized to be 3-O-galloyl-4,6-(S)-dehydrohexahydroxydiphenoyl-D-glucose. Interestingly, acid hydrolysis of this compound afforded ellagic acid, despite the absence of a hexahydroxydiphenoyl group. From the rhizome of Polygonum runcinatum var. sinense, a large amount of granatin A, along with minor ellagitannins, helioscpoinin A, davicratinic acids B and C, and a new ellagitannin called polygonanin A, were isolated. Based on 2D nuclear magnetic resonance (NMR) spectroscopic examination, the structure of polygonanin A was determined to be 1,6-(S)-hexahydroxydiphenoyl-2,4-hydroxychebuloyl-β-D-glucopyranose. These are the second and third hydrolyzable tannins isolated from Polygonaceous plants. In addition, oligomeric proanthocyanidins of Persicaria capitatum and P. chinensis were characterized by thiol degradation. These results suggested that some Polygonaceous plants are the source of hydrolyzable tannins not only proanthocyanidins.
Production of ellagitannin hexahydroxydiphenoyl ester by spontaneous reduction of dehydrohexa-hydroxydiphenoyl ester
Era, Manami,Matsuo, Yosuke,Saito, Yoshinori,Tanaka, Takashi
, (2020/03/17)
Amariin is an ellagitannin with two dehydrohexahydroxydiphenoyl (DHHDP) moieties connecting glucose 2,4- and 3,6-hydroxy groups. This tannin is predominant in the young leaves of Triadica sebifera and Carpinus japonica. However, as the leaves grow, the 3,6-DHHDP is converted to its reduced form, the hexahydroxydiphenoyl (HHDP) group, to generate geraniin, a predominant ellagitannin of the matured leaves. The purified amariin is unstable in aqueous solution, and the 3,6-(R)-DHHDP is spontaneously degraded to give HHDP, whereas 2,4-(R)-DHHDP is stable. The driving force of the selective reduction of the 3,6-DHHDP of amariin is shown to be the conformational change of glucose from O,3B to 1C4. Heating geraniin with pyridine affords 2,4-(R)-DHHDP reduction products. Furthermore, the acid hydrolysis of geraniin yields two equivalents of ellagic acid. Although the reaction mechanism is still ambiguous, these results propose an alternative biosynthetic route of the ellagitannin HHDP groups.
