23094-69-1Relevant academic research and scientific papers
Furosonin, a novel hydrolyzable tannin from geranium thunbergii
Taniguchi, Shoko,Nogaki, Ryouta,Bao, Li-Ming,Kuroda, Teruo,Ito, Hideyuki,Hatano, Tsutomu
, p. 1525 - 1532 (2012)
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.
Size exclusion chromatographic analysis of polyphenol-serum albumin complexes
Hatano, Tsutomu,Hori, Mami,Hemingway, Richard W.,Yoshida, Takashi
, p. 817 - 823 (2003)
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.
Total Synthesis of Mallotusinin
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)
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.
Total synthesis of (-)-corilagin
Yamada, Hidetoshi,Nagao, Kohei,Dokei, Kazutoyo,Kasai, Yusuke,Michihata, Naoki
, p. 7566 - 7567 (2008/12/22)
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
Glutathione-mediated conversion of the ellagitannin geraniin into chebulagic acid
Tanaka, Takashi,Kouno, Isao,Nonaka, Gen-Ichiro
, p. 34 - 40 (2007/10/03)
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.
Tannins and related compounds. CXVIII. Structures, preparation, high-performance liquid chromatography and some reactions of dehydroellagitannin-acetone condensates
Tanaka,Fujisaki,Nonaka,Nishioka
, p. 2937 - 2944 (2007/10/02)
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
REACTION OF DEHYDROELLAGITANNINS WITH L-CYSTEINE METHYL ESTER
Tanaka, Takashi,Fujisaki, Hiroshi,Nonaka, Gen-ichiro,Nishioka, Itsuo
, p. 375 - 383 (2007/10/02)
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.
Tannins and Related Polyphenols of Euphorbiaceous Plants. IV. Euphorbins A and B, Novel Dimeric Dehydroellagitannins from Euphorbia hirta L.
Yoshida, Takashi,Ling Chen,Shingu, Tetsuro,Okuda, Takuo
, p. 2940 - 2949 (2007/10/02)
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
