154-23-4Relevant articles and documents
The epimerase activity of anthocyanidin reductase from Vitis vinifera and its regiospecific hydride transfers
Gargouri, Mahmoud,Chaudiere, Jean,Manigand, Claude,Mauge, Chloe,Bathany, Katell,Schmitter, Jean-Marie,Gallois, Bernard
, p. 219 - 227 (2010)
Anthocyanidin reductase (ANR) from Vitis vinifera catalyzes an NADPH-dependent double reduction of anthocyanidins producing a mixture of (2S,3R)- and (2S,3S)-flavan-3-ols. At pH 7.5 and 30°C, the first hydride transfer to anthocyanidin is irreversible, and no intermediate is released during catalysis. ANR reverse activity was assessed in the presence of excess NADPq. Analysis of products by reverse phase and chiral phase HPLC demonstrates that ANR acts as a flavan-3-ol C3-epimerase under such conditions, but this is only observed with 2R-flavan-3-ols, not with 2S-flavan-3-ols produced by the enzyme in the forward reaction. In the presence of deuterated coenzyme 4S-NADPD, ANR transforms anthocyanidins into dideuterated flavan-3-ols. The regiospecificity of deuterium incorporation into catechin and afzelechin - derived from cyanidin and pelargonidin, respectively - was analyzed by liquid chromatography coupled with electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS), and it was found that deuterium was always incorporated at C2 and C4. We conclude that 3-epimerization should be achieved by tautomerization between the two hydride transfers and that this produces a quinone methide intermediate which serves as C4 target of the second hydride transfer, thereby avoiding any stereospecific modification of carbon 3. The inversion of C2 stereochemistry required for reverse epimerization suggests that the 2S configuration induces an irreversible product dissociation.
PHYLLOFLAVAN, A CHARACTERISTIC CONSTITUENT OF PHYLLOCLADUS SPECIES
Foo, Lai Yeap,Hrstich, Liana,Vilain, Christian
, p. 1495 - 1498 (1985)
Key Word Index - Phyllocladus alpinus; Podocarpaceae; catechin; epicatechin; phylloflavan; epimerization; configuration.Abstract - Selective visulaization of 2D TLC of extracts of Phyllocladus species with vanillin-hydrochloric acid showed a characteristic pattern of constituents attributable to catechin, epicatechin and phylloflavan, a new flavanoid compound.Optical rotation measurements showed that while catechin and epicatechin are of the normal type with the 2R configurations, the flavan moiety in phylloflavan is of the opposite 2S configuration.Spectroscopic data of the new compound and its hydrolysis products showed phylloflavan to be ent-epicatechin-3-δ-(3,4-dihydroxyphenyl)-β-hydroxypentanoate.
Effects of epigallocatechin gallate on the stability of epicatechin in a photolytic process
Huang, Shiuh-Tsuen,Hung, Yi-An,Yang, Meei-Ju,Chen, Iou-Zen,Yuann, Jeu-Ming P.,Liang, Ji-Yuan
, (2019)
Catechins belonging to polyhydroxylated polyphenols are the primary compounds found in green tea. They are associated with many physiological properties. Epicatechin (EC) is a non-gallate-type catechin with four phenolic hydroxyl groups attached. The changes in EC treated with color light illumination in an alkaline condition were investigated by chromatographic and mass analyses in this study. In particular, the superoxide anion radical (O2??) was investigated during the EC photolytic process. EC is unstable under blue light illumination in an alkaline solution. When EC was treated with blue light illumination in an alkaline solution, O2?? was found to occur via a photosensitive redox reaction. In addition, the generation of monomeric, dimeric, and trimeric compounds is investigated. On the other hand, epigallocatechin gallate (EGCG), which is a gallate-type catechin, is stable under blue light illumination in an alkaline solution. Adding EGCG, during the blue light illumination treatment of EC decreased photolytic formation, suggesting that gallate-type catechins can suppress the photosensitive oxidation of EC. Gallate-type catechins are formed via the esterification of non-gallate-type catechins and gallic acid (GA). The carbonyl group on the gallate moiety of gallate-type catechins appears to exhibit its effect on the stability against the photosensitive oxidation caused by blue light illumination.
Phenolic compounds from the rhizomes of Smilax China L. & their anti-inflammatory activity
Zhong, Cheng,Hu, Deng,Hou, Lian-Bing,Song, Lu-Yao,Zhang, Ying-Jun,Xie, Yang,Tian, Li-Wen
, (2017)
A new triflavanoid, kandelin B-5 (1), was isolated from the rhizomes of Smilax China L., together with six known phenylpropanoid substituted flavan-3-ols (2-7), nine flavonoids (8-16), two stilbenoids (17, 18), and two other compounds (19, 20). The structure of compound 1 was determined on the basis of 1D, 2D NMR and HR-ESI-MS data, as well as chemical method. Compounds 2-5, 8-12, 15, 17, and 19 were evaluated for anti-inflammatory activity. Only compounds 10, 15 and 17 showed slightly IL-1expression inhibitory activities on LPS induced THP-1 cells, with inhibition rate of 15.8%, 37.3%, and 35.8%, respectively, at concentration of 50 μg/mL.
POTENTILLANIN, A BIFLAVANOID AND A PROCYANIDIN GLYCOSIDE FROM POTENTILLA VISCOSA
Zhang, Ben,Gen-Ichiro Nonaka,Nishioka, Itsuo
, p. 3277 - 3280 (1988)
An investigation of the root of Potentilla viscosa has led to the isolation and characterization of a novel 6',8-linked bisflavanoid, potentillanin and a procyanidin B-3,3'-O-glucoside.Furthermore, the occurrence of (+)-catechin and its 3-O-glucoside, procyanidins B-3 and C-2 and afzelechin-(4α->8)-catechin was demonstrated.Key Word Index - Potentilla viscosa; Roseceae; potentillanin; bisflavanoid; flavan-3-ol glycoside; procyanidin glycoside; proanthocyanidin.
Kinetics of Epimerization of (+)-Catechin and Its Rearrangement to Catechinic Acid
Kiatgrajai, Preecha,Wellons, J. D.,Gollob, Lawrence,White, James D.
, p. 2910 - 2912 (1982)
The rates of epimerization of (+)-catechin (1) to (+)-epicatechin (2) and of (-)-epicatechin to (-)-catechin in aqueous solution were measuredthe pH range 5.4-11.0 and the temperature range 34-100 deg C.The rate of conversion of (+)-catechin to catechinic acid (3) also was measured under these conditions.First-order kinetics were observed for all three processes.At low pH, k(epimerization) >> k(rearrangement), and epimerization approached an equilibrium in which (+)-catechin predominated(+)-epicatechin.Near pH 11 and at elevated temperatures,k(epimerization) was only slightly greater than k(rearrangement), and the rapid, irreversible formation of catechinic acid under these conditions determined product composition.Both the epimerization of catechin and its rearrangement to catechinic acid can be rationalized in terms of a quinone methide intermediate (4).
Terpenoids of Boswellia neglecta oleo-gum resin
Manguro, Lawrence Onyango Arot,Wagai, Samuel Otieno,Onyango, Joab Otieno
, p. 317 - 323 (2016)
Oleo-gum resin exudate from Boswellia neglecta afforded a new ursane-type triterpene characterized as 3α-acetoxy-28-hydroxy-11-oxours-12-en-24-ioc acid (1) together with twelve known compounds. Their structural elucidation was accomplished using physical, chemical and spectroscopic methods.
FLAVONOID BIOCIDES: PHYTOALEXIN ANALOGUES FROM CONDENSED TANNINS
Laks, Peter E.
, p. 1617 - 1622 (1987)
Flavonoids containing a single alkyl chain can be synthesized from condensed tannins by thiolysis with an alkyl thiol to give epicatechin-4-alkylsulphides.A number of flavonoid derivatives were made with side chains ranging from C6 to C16 and tested for fungitoxic and bactericidal activities.Maximum activity was usually found for the decane derivative.Minimum inhibitory concentrations varied with the organism tested, from about 10 ppm for some rapidly growing fungi and Gram-positive bacteria, to over 500 ppm for other fungi and Gram-negative bacteria.The structural and toxicity characteristics of the epicatechin-4-alkylsulphides suggests they are acting as analogues of prenylated isoflavonoid phytoalexins.Key Word Index - Condensed tannins; phytoalexins; flavonoids; antifungal activity; antibacterial activity.
Chemical and enzymatic synthesis of monomeric procyanidins (leucocyanidins or 3′,4′,5,7-tetrahydroxyflavan-3,4-diols) from (2R,3R)-dihydroquercetin
A. Stafford, Helen,H. Lester, Hope,J. Porter, Lawrence
, p. 333 - 338 (1985)
The major product from the reduction of (2R,3R)-dihydroquercetin with sodium borohydride is the 2,3-trans-3,4-trans isomer of leucocyanidin [(2R,3S,4R-3,3′,4,4′,5,7-hexahydroxyflavan] whereas the enzymatic reduction product is the 2,3-trans-3,4-cis isomer [(2R,3S,4S)-3,3′,4,4′,5,7-hexahydroxyflavan]. The 3,4-trans isomer may be partly converted to the 3,4-cis isomer under mild acid conditions. The 3,4-cis isomer is more acid-labile, and more reactive both chemically with thiols and enzymatically with a diol reductase, than the 3,4-trans isomer.
Flavan-3-ols and procyanidins from the bark of Salix purpurea L.
Juergenliemk,Petereit,Nahrstedt, Adolf
, p. 231 - 234 (2007)
From a commercial aqueous ethanolic extract obtained from the bark of Salix purpurea L. the flavan-3-ols catechin, epicatechin, gallocatechin, catechin-3-O-(1-hydroxy-6-oxo-2-cyclohexene-1-carboxylic acid)-ester, the dimeric procyanidins B1, B3 and the trimeric procyanidins epicatechin- (4β→8)-catechin-(4α→8)-catechin and epicatechin- (4β→8)-epicatechin-(4β→8)-catechin were isolated. Structure elucidation was performed by NMR, CD, MS, degradation and optical rotation methods. A fraction containing higher oligomeric procyanidins was investigated by 13C NMR. Data indicate an average degree of oligomerization of 4 to 5 flavan-3-ol units with dihydroxylated B-rings and predominance of 2,3-cis-stereochemistry.
