- Furosonin, a novel hydrolyzable tannin from geranium thunbergii
-
Furosonin (2), a novel hydrolyzable tannin, was isolated from Geranium thunbergii (Geraniaceae) leaves, and the structure was determined based on spectroscopic data. The effects of geraniin (1), furosonin (2), and related hydrolyzable tannins on antibiotic resistance were examined, and repandusinic acid A (4) was found to suppress oxacillin resistance of methicillin-resistant Staphylococcus aureus.
- Taniguchi, Shoko,Nogaki, Ryouta,Bao, Li-Ming,Kuroda, Teruo,Ito, Hideyuki,Hatano, Tsutomu
-
-
Read Online
- Size exclusion chromatographic analysis of polyphenol-serum albumin complexes
-
Formation of water-soluble polyphenol-protein complexes was investigated by size-exclusion chromatography (SEC). The combination of (-)-epigallocatechin gallate (EGCG) and bovine serum albumin (BSA), which did not form a precipitate after the solutions were mixed, showed an SEC peak due to complex formation 2-24 h after mixing. Peak size of the complex varied with time, suggesting slow change of the conformation of the protein accompanied by complexation. Formation of the complex was substantiated by ultrafiltration of the mixture; the complex did not pass through a membrane with a 100,000 nominal molecular weight limit (NMWL). The SEC profile varied with the combination of compounds. The peaks due to the complexes showed that the apparent value of the number average molecular weight (Mn) of the EGCG-BSA complex was 2.8 × 105, while that of a pentagalloylglucose (PGG)-BSA complex was 9.5 × 105 under the conditions used. Dimeric hydrolyzable tannins, oenothein B and cornusiin A, also caused changes in the SEC profile of BSA, although the combinations did not show peaks attributable to formation of such large complexes observed for EGCG and PGG. Procyanidin B3 and (+)-catechin did not cause changes in the SEC profile of BSA. With cytochrome c, EGCG did not show any chromatographic changes.
- Hatano, Tsutomu,Hori, Mami,Hemingway, Richard W.,Yoshida, Takashi
-
-
Read Online
- Total Synthesis of Mallotusinin
-
The total synthesis of mallotusinin, which bears a tetrahydroxydibenzofuranoyl (THDBF) bridge between the 2-oxygen and 4-oxygen of glucose on corilagin with a 3,6-O-(R)-hexahydroxydiphenoyl (HHDP) bridge, is described. The key features of the total synthesis are: 1) improvements of our previously reported method to synthesize corilagin; 2) establishment of the THDBF skeleton via an unusual intramolecular SNAr reaction of an HHDP analogue, and 3) the application of a two-step bislactonization strategy for a HHDP bridge construction into the 2,4-O-THDBF bridge. Oxidative phenol coupling of 1,2,4-orthoacetyl-3,6-di-(4-O-benzylgalloyl)-α-d-glucopyranose and the orthoester cleavage of the coupling product without the pyranose-furanose ring transformation are key reactions for the improved synthesis of corilagin, which enabled the adequate supply of a corilagin precursor that was required to develop the mallotusinin synthesis. These established methods are expected to help develop the synthesis of other ellagitannins with a bridge between the two oxygens of corilagin.
- Ashibe, Seiya,Ikeuchi, Kazutada,Kume, Yuji,Michihata, Naoki,Puspita, Cicilia A. D.,Tanigawa, Kotaro,Wakamori, Shinnosuke,Yamada, Hidetoshi,Yamashita, Kohei
-
p. 16408 - 16421
(2020/11/30)
-
- Total synthesis of (-)-corilagin
-
The synthesis of corilagin was achieved by the integration of the development of the oxidative coupling of the symmetrically protected gallates and the temporarily ring-opened synthetic route for the 3,6-hexahydroxydiphenoyl (HHDP) bridge. This is the fir
- Yamada, Hidetoshi,Nagao, Kohei,Dokei, Kazutoyo,Kasai, Yusuke,Michihata, Naoki
-
p. 7566 - 7567
(2008/12/22)
-
- Glutathione-mediated conversion of the ellagitannin geraniin into chebulagic acid
-
Geraniin (1), a widely distributed ellagitannin having a dehydrohexahydroxydiphenoyl (DHHDP) ester moiety, was converted into chebulagic acid (2), an ellagitannin having a chebuloyl ester moiety, which was reported to be a potent inhibitor of DNA topoisomerases. This was achieved by addition of the thiol group of glutathione to the six-membered acetal ring form of the DHHDP moiety (1a) with concomitant hydrolytic ring cleavage and subsequent reductive desulfurization with Raney nickel. The concurrent addition of the thiol to the five-membered acetal ring form of the DHHDP group (1b) generated the product 14 and its precursor 13, which are structurally related to naturally occurring ellagitannins isolated from Euphorbiaceous plants. Thus, the rearrangements observed in these reactions may be relevant to the metabolism of DHHDP esters in plants.
- Tanaka, Takashi,Kouno, Isao,Nonaka, Gen-Ichiro
-
-
- Tannins and related compounds. CXVIII. Structures, preparation, high-performance liquid chromatography and some reactions of dehydroellagitannin-acetone condensates
-
The dehydroellagitannins having a dehydrohexahydroxydiphenoyl ester group in the molecule were found to undergo highly regio- and stereospecific condensation with acetone in the presence of ammonium ion under almost neutral conditions. This reaction was s
- Tanaka,Fujisaki,Nonaka,Nishioka
-
p. 2937 - 2944
(2007/10/02)
-
- REACTION OF DEHYDROELLAGITANNINS WITH L-CYSTEINE METHYL ESTER
-
Reaction of dehydroellagitannins (e.g. 1) with L-cysteine methyl ester (5) at room temperature yielded the condensation products (e.g. 3 and 4), together with a partial hydrolysate (e.g. 2), while heating the mixture at 80 deg C afforded 4 and the hydrolysate (2) in fairly good yields.In addition, reduction of a dehydrohexahydroxydiphenoyl ester group to a hexahydroxy-diphenoyl group with thiols is also described.
- Tanaka, Takashi,Fujisaki, Hiroshi,Nonaka, Gen-ichiro,Nishioka, Itsuo
-
p. 375 - 383
(2007/10/02)
-
- Tannins and Related Polyphenols of Euphorbiaceous Plants. IV. Euphorbins A and B, Novel Dimeric Dehydroellagitannins from Euphorbia hirta L.
-
Two new dimeric dehydroellagitannins, named euphorbin A (6) and euphorbin B (7), were isolated from the aerial parts of Euphorbia hirta, and their structures, containing 4C1 and 1C4 glucopyranose residues and a dehydrohexahydroxydiphenoyl group, were elucidated on the basis of chemical and spectral studies.Five monomeric hydrolizable tannins, i.e., 2,4,6-tri-O-galloyl-D-glucose, 1,3,4,6-tetra-O-galloyl-β-D-glucose, 1,2,3,4,6-penta-O-galloyl-β-D-glucose, geraniin and terchebin, as well as two quinic acid esters, i.e., 5-O-caffeoylquinic acid and 3,4-di-O-galloylquinic acid, and three flavonol glycosides were also isolated.Keywords - Euphorbia hirta; Euphorbiaceae; tannin; dimeric hydrolyzable tannin; euphorbin A; euphorbin B; dehydrohexahydroxydiphenoyl group; dehydroellagitannin
- Yoshida, Takashi,Ling Chen,Shingu, Tetsuro,Okuda, Takuo
-
p. 2940 - 2949
(2007/10/02)
-
- PUNICAFOLIN, AN ELLAGITANNIN FROM THE LEAVES OF PUNICA GRANATUM
-
A new ellagitannin, punicafolin has been isolated from the leaves of Punica granatum and characterized by physicochemical data and spectral evidence as 1,2,4-tri-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-β-D-glucose.The occurrence in the leaves of the known tannins, granatins A and B, corilagin, strictinin, 1,2,4,6-tetra-O-galloyl-β-D-glucose and 1,2,3,4,6-penta-O-galloyl-β-D-glucose has also been demonstrated.Key Word Index -Punica granatum; Punicaceae; pomegranate; punicafolin; ellagitannin; gallotannin.
- Tanaka, Takashi,Nonaka, Gen-Ichiro,Nishioka, Itsuo
-
p. 2075 - 2078
(2007/10/02)
-
- The Metabolism of Gallic Acid and Hexahydroxydiphenic Acid in Plants. Part 3. Esters of (R)- and (S)-Hexahydroxydiphenic Acid and Dehydrohexahydroxydiphenic acid with D-Glucopyranose (1C4 and Related Conformations)
-
In a small group of plants a process of further metabolism of galloyl-D-glucose esters occurs in which oxidative coupling takes place between galloyl ester groups in the 1,6:2,4 or 3,6-position of D-glucopyranose in its least favoured 1C4
- Haddock, Elizabeth A.,Gupta, Raj K.,Haslam, Edwin
-
p. 2535 - 2546
(2007/10/02)
-
