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.
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.
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.
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Nonaka,G.,Miwa,N.
, p. 429 (1982)
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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.
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.
Biochemical and functional characterization of anthocyanidin reductase (ANR) from Mangifera indica L.
Tan, Lin,Wang, Mei,Kang, Youfa,Azeem, Farrukh,Zhou, Zhaoxi,Tuo, Decai,Rojo, Lina María Preciado,Khan, Ikhlas A.,Pan, Zhiqiang
, (2018)
Mango (Mangifera indica L.) is abundant in proanthocyanidins (PAs) that are important for human health and plant response to abiotic stresses. However, the molecular mechanisms involved in PA biosynthesis still need to be elucidated. Anthocyanidin reductase (ANR) catalyzes a key step in PA biosynthesis. In this study, three ANR cDNAs (MiANR1-1,1-2,1-3) were isolated from mango, and expressed in Escherichia coli. In vitro enzyme assay showed MiANR proteins convert cyanidin to their corresponding flavan-3-ols, such as (—)-catechin and (—)-epicatechin. Despite high amino acid similarity, the recombinant ANR proteins exhibited differences in enzyme kinetics and cosubstrate preference. MiANR1-2 and MiANR1-3 have the same optimum pH of 4.0 in citrate buffer, while the optimum pH for MiANR1-1 is pH 3.0 in phosphate buffer. MiANR1-1 does not use either NADPH or NADH as co-substrate while MiANR1-2/1-3 use only NADPH as co-substrate. MiANR1-2 has the highest Km and Vmax for cyanidin, followed by MiANR1-3 and MiANR1-1. The overexpression of MiANRs in ban mutant reconstructed the biosynthetic pathway of PAs in the seed coat. These data demonstrate MiANRs can form the ANR pathway, leading to the formation of two types of isomeric flavan-3-ols and PAs in mango.
Study on in Vitro Preparation and Taste Properties of N-Ethyl-2-Pyrrolidinone-Substituted Flavan-3-Ols
Han, Zisheng,Ho, Chi-Tang,Jiang, Zongde,Lai, Guoping,Qin, Chunyin,Wan, Xiaochun,Wen, Mingchun,Zhai, Xiaoting,Zhang, Hui,Zhang, Liang
, (2022/04/07)
N-ethyl-2-pyrrolidinone-substituted flavan-3-ols (EPSFs) were prepared by an in vitro model reaction, and the taste thresholds of EPSFs and their dose-over-threshold factors in large-leaf yellow tea (LYT) were investigated. The effects of initial reactant
Benzophenone Glucosides and B-Type Proanthocyanidin Dimers from Zambian Cassia abbreviata and Their Trypanocidal Activities
Choongo, Kennedy,Ishikawa, Yoshinobu,Kikuchi, Takashi,Munsimbwe, Linous,Murata, Toshihiro,Shirakura, Izumi,Suganuma, Keisuke
, p. 91 - 104 (2022/01/20)
Two benzophenone glucosides (1 and 2), five flavan-3-ol dimers (5–9), and 17 known compounds (3, 4, and 10–24) were identified from the bark extract of Cassia abbreviata. The chemical structures display two points of interest. First, as an unusual charact
11-β-hydroxysterols as possible endogenous stimulators of mitochondrial biogenesis as inferred from epicatechin molecular mimicry
Dugar, Sundeep,Villarreal, Francisco,Hollinger, Frank H.,Mahajan, Dinesh,Ramirez-Sanchez, Israel,Moreno-Ulloa, Aldo,Ceballos, Guillermo,Schreiner, George
, (2019/11/28)
Currently, there is great interest in identifying endogenous (i.e. physiological) stimulators of mitochondrial biogenesis (MB), in particular, those that may mediate the effects of exercise. The molecular size of the cacao flavanols (epicatechin and catechin) highly resembles that of sterols and epicatechin has been reported to activate cells surface receptors leading to the stimulation of MB in endothelial and skeletal muscle cells translating into enhanced exercise capacity. We therefore hypothesize, that epicatechin may be acting as a structural mimic of an as yet unknown sterol capable of stimulating MB. We developed a new synthetic process for obtaining enantiomerically pure preparations of (-)-epicatechin and (+)-epicatechin. Applying spatial analytics and molecular modeling, we found that the two isoforms of epicatechin, (-) and (+), have a structural resemblance to 11-β-hydroxypregnenolone, a sterol with no previously described biological activity. As reported in this proof-of-concept study performed in primary cultures of endothelial and muscle cells, 11-β-hydroxypregnenolone is one of the most potent inducers of MB as significant activity can be detected at femtomolar levels. The relative potency of (-)/(+)-epicatechin isoforms and on inducing MB correlates with their degree of spatial homology towards the 11-β-hydroxypregnenolone. On the basis of these results, the detailed in vivo characterization of the potential for these sterols to act as endogenous modulators of MB is warranted.
