- Catechin
-
Catechin (2R,3S)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triolOther namesCatechol
Cianidanol
Cyanidanol
(+)-catechin
D-Catechin
Catechinic acid
Catechuic acid
Cianidol
Dexcyanidanol
(2R,3S)-Catechin
2,3-trans-catechin
3,3',4',5,7–flavanpentolIdentifiers CAS number 7295-85-4 , (±)
154-23-4 (+)
18829-70-4 (-)PubChem 9064 ChemSpider 8711 UNII 8R1V1STN48 ChEBI CHEBI:15600 ChEMBL CHEMBL251445 Jmol-3D images Image 1 - Oc1ccc(cc1O)[C@H]3Oc2cc(O)cc(O)c2C[C@@H]3O
Properties Molecular formula C15H14O6 Molar mass 290.26 g/mol Exact mass 290.079038 Appearance Colorless solid Melting point 175–177 °C
λmax 276 nm Chiral rotation [α]D +14.0° Hazards MSDS sciencelab AppliChem R-phrases R36/R37/R38 S-phrases S26-S36 Main hazards Mutagenic for mammalian somatic cells, mutagenic for bacteria and/or yeast LD50 (+)-catechin : 10,000 mg/kg in rat (RTECS)
10,000 mg/kg in mouse
3,890 mg/kg in rat (other source)Pharmacology Routes of
administrationOral Excretion Urines (verify) (what is:
/
?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)Infobox references Catechin (
/ˈkætɨtʃɪn/) is a natural phenol antioxidant plant secondary metabolite. The term catechins is also commonly used to refer to the related family of flavonoids and the subgroup flavan-3-ols (or simply flavanols).
The name of the catechin chemical family derives from catechu, which is the juice or boiled extract of Mimosa catechu (Acacia catechu L.f) [1]
Contents
Chemistry
Catechin possesses two benzene rings (called the A- and B-rings) and a dihydropyran heterocycle (the C-ring) with a hydroxyl group on carbon 3. The A ring is similar to a resorcinol moiety while the B ring is similar to a catechol moiety. There are two chiral centers on the molecule on carbons 2 and 3. Therefore, it has four diastereoisomers. Two of the isomers are in trans configuration and are called catechin and the other two are in cis configuration and are called epicatechin.
The most common catechin isomer is the (+)-catechin. The other stereoisomer is (-)-catechin or ent-catechin. The most common epicatechin isomer is (-)-epicatechin (also known under the names L-epicatechin, epicatechol, (-)-epicatechol, l-acacatechin, l-epicatechol, epi-catechin, 2,3-cis-epicatechin or (2R,3R)-(-)-epicatechin).
The different epimers can be distinguished using chiral column chromatography.[2]
Making reference to no particular isomer, the molecule can just be called catechin. Mixtures of the different enantiomers can be called (+/-)-catechin or DL-catechin and (+/-)-epicatechin or DL-epicatechin.
- Diastereoisomers gallery
Moreover, the flexibility of the C-ring allows for two conformation isomers, putting the B ring either in a pseudoequatorial position (E conformer) or in a pseudoaxial position (A conformer). Studies confirmed that (+)-catechin adopts a mixture of A- and E-conformers in aqueous solution and their conformational equilibrium has been evaluated to be 33:67.[3]
Regarding the antioxidant activity, (+)-catechin has been found to be the most powerful scavenger between different members of the different classes of flavonoids. The ability to quench singlet oxygen seems to be in relation with the chemical structure of catechin, with the presence of the catechol moiety on ring B and the presence of a hydroxyl group activating the double bond on ring C.[4]
Catechin exists in the form of a glycoside.[5] Antioxidant properties can also be provided using a catechin associated with a sugar. In 1975-76, a group of USSR scientists of Kaz ssr discovered first the catechin rhamnoside using the plants of Filipendula that grow in that region. Pioneer and head of the discovery was PhD N. D. Storozhenko born in 1944. Though not thoroughly studied, the rhamnoside of catechin can enter the blood cell without breaking the outer layer.
Oxidation
Electrochemical experiments show that (+)-catechin oxidation mechanism proceeds in sequential steps, related with the catechol and resorcinol groups and the oxidation is pH-dependent. The oxidation of the catechol 3′,4′-dihydroxyl electron-donating groups occurs first, at very low positive potentials, and is a reversible reaction. The hydroxyl groups of the resorcinol moiety oxidised afterwards were shown to undergo an irreversible oxidation reaction.[6]
Spectral Data
UV-Vis Lambda-max: 276 nm Extinction coefficient (log ε) 4.01 IR Major absorption bands 1600 cm−1(benzene rings) NMR Proton NMR
(500 MHz, CD3OD):
Reference[7]
d : doublet, dd : doublet of doublets,
m : multiplet, s : singletδ :
2.49 (1H, dd, J = 16.0, 8.6 Hz, H-4a),
2.82 (1H, dd, J = 16.0, 1.6 Hz, H-4b),
3.97 (1H, m, H-3),
4.56 (1H, d, J = 7.8 Hz, H-2),
5.86 (1H, d, J = 2.1 Hz, H-6),
5.92 (1H, d, J = 2.1 Hz, H-8),
6.70 (1H, dd, J = 8.1, 1.8 Hz, H-6′),
6.75 (1H, d, J = 8.1 Hz, H-5′),
6.83 (1H, d, J = 1.8 Hz, H-2′)Carbon-13 NMR Other NMR data MS Masses of
main fragmentsESI-MS [M+H]+ m/z : 291.0
273 water loss
139 Retro Diels Alder
123
165
147Sources
(+)-catechin and (-)-epicatechin are found in the traditional Chinese medicine plant Uncaria rhynchophylla.[8] Potentilla fragarioides, also used in traditional Chinese medicine, contains D-catechin.[9]
A racemic mixture of (+)-catechin and (-)-catechin is released from the roots of the invasive weed, Centaurea maculosa, the spotted knapweed. It acts as an herbicide to inhibit competition by a wide range of other plant species. This phytotoxic compound inhibits seed germination and growth.[10]
In food
Main articles: Phenolic content in tea and Phenolic content in winel-Epicatechin can be found in cacao beans and was first called kakaool.[11] The different other enantiomers can as well be found in chocolate where the different processes of fabrication can lead to epimerisation by heating. The kola nut, a related species, contains epicatechin and D-catechin. Açaí oil, obtained from the fruit of tha açaí palm (Euterpe oleracea), is rich in (+)-catechin (66.7 +/- 4.8 mg/kg).[12]
Taste
The taste associated with monomeric (+)-catechin or (-)-epicatechin is described as not exactly astringent, nor exactly bitter.[13] It is envisaged to encapsulate catechin in cyclodextrins to mask its taste to use it as an additive.[3]
Metabolism
Biosynthesis
Leucocyanidin reductase (LCR) uses 2,3-trans-3,4-cis-leucocyanidin to produce (+)-catechin and is the first enzyme in the proanthocyanidins (PA)-specific pathway. Its activity has been measured in leaves, flowers, and seeds of the legumes Medicago sativa, Lotus japonicus, Lotus uliginosus, Hedysarum sulfurescens, and Robinia pseudoacacia.[14] The enzyme is also present in Vitis vinifera (grape).[15]
Biodegradation
Catechin oxygenase, a key enzyme in the degradation of catechin, is present in fungi and bacteria.[16]
Among bacteria, degradation of (+)-catechin can be achieved by Acinetobacter calcoaceticus. Catechin is metabolized to protocatechuic acid (PCA) and phloroglucinol carboxylic acid (PGCA).[17] It is also degraded by Bradyrhizobium japonicum. Phloroglucinol carboxylic acid is further decarboxylated to phloroglucinol, which is dehydroxylated to resorcinol. Resorcinol is hydroxylated to hydroxyquinol. Protocatechuic acid and hydroxyquinol undergo intradiol cleavage through protocatechuate 3,4-dioxygenase and hydroxyquinol 1,2-dioxygenase to form β-carboxy cis, cis-muconic acid and maleyl acetate.[18]
Among fungi, degradation of catechin can be achieve by Chaetomium cupreum.[19]
In rats, all plasma catechin metabolites are present as conjugated forms and mainly constituted by glucuronidated derivatives. In the liver, the concentrations of catechin derivatives are lower than in plasma, and no accumulation is observed when the rats are adapted for 14 days to the supplemented diets. The hepatic metabolites are intensively methylated (90–95%), but in contrast to plasma, some free aglycones can be detected.[20] Rats fed with (+)-catechin and (-)-epicatechin exhibit (+)-catechin 5-O-β-glucuronide and (-)-epicatechin 5-O-β-glucuronide in their body fluids.[21] The primary metabolite of (+)-catechin in plasma is glucuronide in the nonmethylated form. In contrast, the primary metabolites of (-)-epicatechin in plasma are glucuronide and sulfoglucuronide in nonmethylated forms, and sulfate in the 3'-O-methylated forms (3'OMC).[22] Catechin is absorbed into intestinal cells and metabolized extensively because no native catechin can be detected in plasma from the mesenteric vein. Mesenteric plasma contains glucuronide conjugates of catechin and 3'-O-methyl catechin, indicating the intestinal origin of these conjugates. Additional methylation and sulfation occur in the liver, and glucuronide or sulfate conjugates of 3'OMC are excreted extensively in bile. Circulating forms are mainly glucuronide conjugates of catechin and 3'OMC.[23] Another study shows that catechin undergoes enzymatic oxidation by tyrosinase in the presence of glutathione (GSH) to form mono-, bi-, and tri-glutathione conjugates of catechin and mono- and bi-glutathione conjugates of a catechin dimer.[24]
In the crab eating macaque Macaca iris, (+)-catechin administered orally or intraperitonally leads to the formation of 10 metabolites and notably to m-hydroxyphenylhydracrylic acid excreted in the urine.[25]
In man, (+)-catechin absorbed orally is metabolized largely within 24 hours with the production of eleven metabolites detected in the urine.[26]
Biotransformation
Biotransformation of (+)-catechin into taxifolin by a two-step oxidation can be achieved by Burkholderia sp.[27]
The laccase/ABTS system oxidizes (+)-catechin to oligomeric products[28] of which proanthocyanidin A2 is a dimer.
(+)-Catechin and (-)-epicatechin are transformed by the endophytic filamentous fungus Diaporthe sp. into the 3,4-cis-dihydroxyflavan derivatives, (+)-(2R,3S,4S)-3,4,5,7,3',4'-hexahydroxyflavan (leucocyanidin) and (-)-(2R,3R,4R)-3,4,5,7,3',4'-hexahydroxyflavan, respectively, whereas (-)-catechin and (+)-epicatechin with a 2S-phenyl group resisted the biooxidation.[29]
Leucoanthocyanidin reductase (LAR) uses (2R,3S)-catechin, NADP+ and H2O to produce 2,3-trans-3,4-cis-leucocyanidin, NADPH, and H+. Its gene expression has been studied in developing grape berries and grapevine leaves.[30]
Catechin and epicatechin are the building blocks of the proanthocyanidins, a type of condensed tannin.
Bioactivity studies
Catechin is reported to induce longevity in the nematode worm Caenorhabditis elegans.[31] Transcriptomic studies shows that catechin reduces atherosclerotic lesion development in apo E-deficient mice.[32] (+)- and (−)-catechin seem to have stereospecific opposite effects on glycogen metabolism in isolated rat hepatocytes.[33] (+)-Catechin inhibits intestinal tumor formation in mice.[34] (+)-Catechin inhibits the oxidation of low density lipoprotein.[35]
(-)-Catechin suppresses expression of Kruppel-like factor 7.[36]
Catechin shows an enhancement of the antifungal effect of amphotericin B against Candida albicans.[37]Incubation experiments with (+)-catechin show a prevention of human plasma oxidation.[38]
Interactions with human genes
Catechin interacts the most with the PTGS2, IL1B, CAT, CYP1A1, SOD, BAX, CASP3, MAPK1, MAPK3 and S100B human genes.[39]
PTGS2 (aka COX-2 for cyclooxygenase-2) is a dioxygenase. The presence of catechin seems to increase its expression.
IL1B induces the formation of cyclooxygenase-2 (PTGS2/COX2). Catechin increases its expression.
CAT is a catalase. Catechin decreases its expression.
CYP1A1 (Cytochrome P450, family 1, member A1) is an enzyme implied in the metabolism of xenobiotics. Catechin decreases its expression.
SOD (Superoxide dismutase) is an enzyme that catalyzes the dismutation of superoxide into oxygen and hydrogen peroxide. Catechin increases its expression.
BAX (Bcl-2–associated X protein) is a protein of the Bcl-2 gene family. It promotes apoptosis by competing with Bcl-2 proper. Catechin increases its expression.
CASP3 (Caspase 3) is a protein that plays a central role in the execution-phase of cell apoptosis. Catechin increases its expression.
MAPK1 (Mitogen-activated protein kinase 1) and MAPK3 (Mitogen-activated protein kinase 3) are enzymes that are extracellular signal-regulated kinases (ERKs) and act as an integration point for multiple biochemical signals, involved in a wide variety of cellular processes such as proliferation, differentiation, transcription regulation, and development. Catechin seems to increase their expression.
S100B (S100 calcium binding protein B) is an pro-inflammatory enzyme specific of mature astrocytes that ensheath the blood vessels. Catechin decreases the expression of the gene and could regulate S100B-activated oxidant stress-sensitive pathways through blocking p47phox protein expression. Treatment with catechin could eliminate reactive oxygen species (ROS) to reduce oxidative stress stimulated by S100B. Catechin decreases its expression.Experiments on human Caco-2 cells show changes in the expression of genes like STAT1, MAPKK1, MRP1 and FTH1 genes, which are involved in the cellular response to oxidative stress, are in agreement with the antioxidant properties of catechin. In addition, the changes in the expression of genes like C/EBPG, topoisomerase 1, MLF2 and XRCC1 suggest novel mechanisms of action at the molecular level.[40]
Detail for all tested genes :
(dec : decreased expression, inc : increased expression, = : does not affect the activity, expression assayed in human if not specified otherwise)[41]
ABCG2 : (-)-catechin decreases the expression of ABCG2
ACE (in Rattus norvegicus) : (+)-catechin or (-)-epicatechin do not affect the activity of the angiotensin-converting enzyme
ACTB (in Rattus norvegicus) decrease
AKT1 decrease
ANXA2 increase
ARHGAP4 decrease
ATF4 increase
BAT2 increase
BAX (rattus norvegicus) increase
BCL2 decrease
BRCC3 decrease
BTG1 increase
CASP3 increase
CAT (mus musculus) decrease
CCL2 increase
CCND1 decrease
CD81 increase
CD9 increase
CEBPG increase
CXCL10 increase
CYP19A1 (rattus norvegicus) increase
CYP1A1 decrease
CYP1A2 =
DEK decrease
DFFA (mus musculus) decrease
DNMT1 decrease
EWSR1 increase
FLT3LG decrease
FTH1 increase
GRN increase
HCFC1 increase
HEAB decrease
HMOX1 increase
HOXD3 increase
HSPD1 decrease
ICAM1 increase
IL10 increase
IL1B increase
IL2RA decrease
IL32 decrease
IRF4 decrease
ITGAL increase
ITGB2 increase
LYN decrease
MAP2K1 decrease ?
MAPK1 increase ?
MAPK3 increase ?
MIF decrease
NCF1 ?
NFE2L2 increase
NFKBIA decrease
NOS2 (mus musculus) increase
NOTCH1 increase
NPM1 decrease
PARP1 (mus musculus) increase
PECAM1 increase
PLAT increase
PLAU increase
PON1 =
PTGS2 increase?
RAC1 decrease
RARB decrease
RELA decrease
RPL6 increase
S100B decrease
SERPINE1 decrease
SF1 decrease
SLC20A1 increase
SOD (Drosophila melanogaster) increase
SOD2 (Drosophila melanogaster) increase
STAT1 decrease
STAT5B increase
STAT6 increase
SULT1A1 increase : sulfation of catechin
TCF7 increase
TK1 decrease
TNF increase
TNFRSF8 decrease
TOP1 decrease
TOP2A decrease
TRP53 increase
XCR1 decrease
ZNF593 increaseHealth benefits
Protection of the mouse brain after a stroke
Ninety minutes after feeding mice a single modest dose of epicatechin, a compound found naturally in dark chocolate, the scientists induced an ischemic stroke by, in essence, cutting off blood supply to the animals' brains. They found that the animals that had preventively ingested the epicatechin suffered significantly less brain damage than the ones that had not been given the compound. While most treatments against stroke in humans have to be given within a two- to three-hour time window to be effective, epicatechin appeared to limit further neuronal damage when given to mice 3.5 hours after a stroke. Given six hours after a stroke, however, the compound offered no protection to brain cells.[42]
Histidine decarboxylase inhibitor
(+)-Catechin is a histidine decarboxylase inhibitor. Thus, it inhibits the conversion of histidine to histamine, and, so, is thought to be beneficial through reduction of potentially damaging, histamine-related local immune response(s).[43]
Monoamine oxidase inhibitor
(+)-Catechin and (-)-epicatechin are also selective monoamine oxidase inhibitors (MAOIs) of type MAO-B. They could be used as part of the treatment of Parkinson's and Alzheimer's patients.[8]
Ecological effects
Catechin also has ecological functions.
It is released into the ground by some plants to hinder the growth of their neighbors, a form of allelopathy.[44] Centaurea maculosa, the spotted knapweed, is the most studied plant showing this behaviour, catechin isomers, both released into the ground through its root exudates, have effects ranging from antibiotic to herbicide. It causes a reactive oxygen species wave through the target plant's root starting in the apical meristem rapidly followed by a Ca2+ spike that kills the root cells through apoptosis.[45] Most plants in the European ecosystem have defenses against catechin, but few plants are protected against it in the North-American ecosystem where Centaurea maculosa has been introduced causing uncontrolled growth of this weed.
(+)-Catechin acts as an infection-inhibiting factor in strawberry leaf.[46] Epicatechin and catechin may prevent coffee berry disease by inhibition of appressorial melanization of Colletotrichum kahawae.[47]
Other uses
It has been suggested that (+)-catechin could be used as a scavenger for indoor air pollutents such as volatile organic compounds (VOC)[48] to adapt for instance as filters to air conditioners or to air purifiers.
References
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- ^ Determination of catechin diastereomers from the leaves of Byrsonima species using chiral HPLC-PAD-CD. Rinaldo D, Batista JM Jr, Rodrigues J, Benfatti AC, Rodrigues CM, Dos Santos LC, Furlan M, Vilegas W, Chirality. 2010 Feb 8.
- ^ a b Investigation of the complexation of (+)-catechin by β-cyclodextrin by a combination of NMR, microcalorimetry and molecular modeling techniques. Zdenek Kríz, Jaroslav Koca, Anne Imberty, Aurélia Charlot and Rachel Auzély-Velty, Org.Biomol.Chem. ,2003,1, 2590–2595
- ^ Antioxidant activity of flavonoids: Efficiency of singlet oxygen (1Δg) quenching. Cécile Tournaire, Sylvie Croux, Marie-Thérèse Maurette, Irena Beck, Michel Hocquaux, André M. Braun and Esther Oliveros, Journal of Photochemistry and Photobiology B: Biology, Volume 19, Issue 3, August 1993, Pages 205-215, doi:10.1016/1011-1344(93)87086-3
- ^ Catechin 7-rhamnoside from Spiraea hypericifolia. T. K. Chumbalov, L. T. Pashinina and N. D. Storozhenko, Chemistry of Natural Compounds, Volume 12, Number 2, 232-233, doi:10.1007/BF00566356
- ^ Catechin electrochemical oxidation mechanisms. Patricia Janeiro and Ana Maria Oliveira Brett, Analytica Chimica Acta, Volume 518, Issues 1-2, 2 August 2004, Pages 109-115, doi:10.1016/j.aca.2004.05.038
- ^ Neural cell protective compounds isolated from Phoenix hanceana var. formosana. Yi-Pei Lin, Tai-Yuan Chen, Hsiang-Wen Tseng, Mei-Hsien Lee and Shui-Tein Chen, Phytochemistry, Volume 70, Issue 9, June 2009, Pages 1173-1181
- ^ a b Hou WC, Lin RD, Chen CT, Lee MH (August 2005). "Monoamine oxidase B (MAO-B) inhibition by active principles from Uncaria rhynchophylla". J Ethnopharmacol 100 (1–2): 216–20. doi:10.1016/j.jep.2005.03.017. PMID 15890481.
- ^ http://www.pfaf.org/database/plants.php?Potentilla+fragarioides
- ^ Bais HP, Walker TS, Stermitz FR, Hufbauer RA, Vivanco JM (April 2002). "Enantiomeric-dependent phytotoxic and antimicrobial activity of (±)-catechin. A rhizosecreted racemic mixture from spotted knapweed". Plant Physiol. 128 (4): 1173–9. doi:10.1104/pp.011019. PMID 11950966. http://www.plantphysiol.org/cgi/content/full/128/4/1173.
- ^ The catechin of the cacao bean. Karl Freudenberg, Richard F. B. Cox, Emil Braun, J. Am. Chem. Soc., 1932, 54 (5), pp 1913–1917, DOI: 10.1021/ja01344a026
- ^ Pacheco-Palencia LA, Mertens-Talcott S, Talcott ST (Jun 2008). "Chemical composition, antioxidant properties, and thermal stability of a phytochemical enriched oil from Acai (Euterpe oleracea Mart.)". J Agric Food Chem 25 (56): 4631–6. doi:10.1021/jf800161u. PMID 18522407.
- ^ Oral sensations associated with the flavan-3-ols (+)-catechin and (−)-epicatechin. S. Kielhorn and J. H. Thorngate III, Food Quality and Preference, Volume 10, Issue 2, March 1999, Pages 109-116, doi:10.1016/S0950-3293(98)00049-4
- ^ Leucocyanidin reductase activity and accumulation of proanthocyanidins in developing legume tissues, B Skadhauge, MY Gruber, KK Thomsen and DV Wettstein
- ^ Crystal Structure and Catalytic Mechanism of Leucoanthocyanidin Reductase from Vitis vinifera. Chloé Maugé, Thierry Granier, Béatrice Langlois d'Estaintot, Mahmoud Gargouri, Claude Manigand, Jean-Marie Schmitter, Jean Chaudière and Bernard Gallois, Journal of Molecular Biology, Volume 397, Issue 4, 9 April 2010, Pages 1079-1091, doi:10.1016/j.jmb.2010.02.002
- ^ Biodegradation of Catechin. M Arunachalam, M Mohan Raj, N Mohan and A Mahadevan, Proc. Indian natn Sci Acad. B69 No. 4 pp 353-370 (2003)
- ^ Degradation of (+)-catechin by Acinetobacter calcoaceticus MTC 127. M. Arunachalam, N. Mohan, R. Sugadev, P. Chellappan and A. Mahadevan, Biochimica et Biophysica Acta (BBA), Volume 1621, Issue 3, 11 June 2003, Pages 261-265, doi:10.1016/S0304-4165(03)00077-1
- ^ Degradation of catechin by Bradyrhizobium japonicum. Waheeta Hopper and A. Mahadevan, Biodegradation, Numéro Volume 8, Number 3 / may 1997, Pages 159-165, DOI 10.1023/A:1008254812074
- ^ Degradation of catechin and purification and partial characterization of catechin oxygenase from Chaetomium cupreum. T. Sambandam and A. Mahadevan, World Journal of Microbiology and Biotechnology, Volume 9, Number 1 / january 1993, Pages 37-44, DOI 10.1007/BF00656513
- ^ Comparison of the bioavailability of quercetin and catechin in rats. Claudine Manach, Odile Texier, Christine Morand, Vanessa Crespy, Françoise Régérat, Christian Demigné and Christian Rémésy, Free Radical Biology and Medicine, Volume 27, Issues 11-12, December 1999, Pages 1259-1266, doi:10.1016/S0891-5849(99)00159-8
- ^ Identification of the Major Antioxidative Metabolites in Biological Fluids of the Rat with Ingested (+)-Catechin and (-)-Epicatechin. Masami Harada, Yukiko Kan, Hideo Naoki, Yuko Fukui, Norihiko Kageyama, Masaaki Nakai, Wataru Miki and Yoshinobu Kis, Bioscience, Biotechnology, and Biochemistry, Vol. 63 (1999), No. 6 pp.973-977
- ^ In Vivo Comparison of the Bioavailability of (+)-catechin, (-)-epicatechin and their mixture in orally administered rats. Seigo Baba, Naomi Osakabe, Midori Natsume, Yuko Muto, Toshio Takizawa and Junji Terao, The American Society for Nutritional Sciences J. Nutr. 131:2885-2891, November 2001
- ^ Catechin is metabolized by both the small intestine and liver of rats. Jennifer L. Donovan, Vanessa Crespy, Claudine Manach, Christine Morand, Catherine Besson, Augustin Scalbert and Christian Rémésy, Journal of Nutrition. 2001;131:1753-1757
- ^ Catechin Metabolism: Glutathione Conjugate Formation Catalyzed by Tyrosinase, Peroxidase, and Cytochrome P450. Majid Y. Moridani, Hugh Scobie, Par Salehi and Peter J. O'Brien, Chem. Res. Toxicol., 2001, 14 (7), pp 841–848, DOI: 10.1021/tx000235o
- ^ Studies on flavonoid metabolism: Excretion of m-Hydroxyphenylhydracrylic Acid from (+)-Catechin in the Monkey (Macaca iris sp.). N. P. Das, Drug Metab Dispos May 1974 2:209-213
- ^ Studies on flavonoid metabolism: Absorption and metabolism of (+)-catechin in man. N.P. Das, Biochemical Pharmacology, Volume 20, Issue 12, December 1971, Pages 3435-3445, doi:10.1016/0006-2952(71)90449-7
- ^ Biotransformation of (+)-catechin into taxifolin by a two-step oxidation: Primary stage of (+)-catechin metabolism by a novel (+)-catechin-degrading bacteria, Burkholderia sp. KTC-1, isolated from tropical peat. Motoki Matsuda, Yuichiro Otsuka, Shigeki Jin, Jun Wasaki, Jun Watanabe, Toshihiro Watanabe and Mitsuru Osaki, Biochemical and Biophysical Research Communications, Volume 366, Issue 2, 8 February 2008, Pages 414-419, doi:10.1016/j.bbrc.2007.11.157
- ^ The laccase/ABTS system oxidizes (+)-catechin to oligomeric products. A.M. Osman, K.K.Y. Wong and A. Fernyhough, Enzyme and Microbial Technology, Volume 40, Issue 5, 3 April 2007, Pages 1272-1279, doi:10.1016/j.enzmictec.2006.09.018
- ^ Biooxidation of (+)-Catechin and (-)-Epicatechin into 3,4-Dihydroxyflavan Derivatives by the Endophytic Fungus Diaporthe sp. Isolated from a Tea Plant. Shibuya Hirotaka, Agusta Andria, Ohashi Kazuyoshi, Maehara Shoji and Simanjuntak Partomuan, Chem Pharm Bull, Vol.53, No.7, Pages 866-867(2005)
- ^ Proanthocyanidin Synthesis and Expression of Genes Encoding Leucoanthocyanidin Reductase and Anthocyanidin Reductase in Developing Grape Berries and Grapevine Leaves, Jochen Bogs, Mark O. Downey, John S. Harvey, Anthony R. Ashton, Gregory J. Tanner and Simon P. Robinson, 2005
- ^ Catechin induced longevity in C. elegans: From key regulator genes to disposable soma. Nadine Saul, Kerstin Pietsch, Ralph Menzel, Stephen R. Stürzenbaum and Christian E.W. Steinberg, Mechanisms of Ageing and Development, Volume 130, Issue 8, August 2009, Pages 477-486, doi:10.1016/j.mad.2009.05.005
- ^ Catechin reduces atherosclerotic lesion development in apo E-deficient mice: A transcriptomic study. Sylvain Auclair, Dragan Milenkovic, Catherine Besson, Stéphanie Chauvet, Elyett Gueux, Christine Morand, Andrzej Mazur and Augustin Scalbert, Atherosclerosis, Volume 204, Issue 2, June 2009, Pages e21-e27, doi:10.1016/j.atherosclerosis.2008.12.007
- ^ Stereospecific effects of (+)- and (−)-catechins on glycogen metabolism in isolated rat hepatocytes. Fritz Nyfeler, Ulrich K. Moser and Paul Walter, Biochimica et Biophysica Acta (BBA), doi:10.1016/0167-4889(83)90024-1
- ^ (+)-Catechin Inhibits Intestinal Tumor Formation and Suppresses Focal Adhesion Kinase Activation in the Min/+ Mouse. Michael J. Weyant, Adelaide M. Carothers, Andrew J. Dannenberg and Monica M. Bertagnolli, Cancer Research 61, 118-125, January 1, 2001
- ^ The inhibition of the oxidation of low density lipoprotein by (+)-Catechin, a naturally occurring flavonoid. Heather Mangiapane, John Thomson, Andrew Saltera, Stuart Brown, G.Duncan Bell and David A. White, Biochemical Pharmacology, Volume 43, Issue 3, 4 February 1992, Pages 445-450, doi:10.1016/0006-2952(92)90562-W
- ^ (-)-Catechin suppresses expression of Kruppel-like factor 7 and increases expression and secretion of adiponectin protein in 3T3-L1 cells. Cho SY, Park PJ, Shin HJ, et al. (2007). Am. J. Physiol. Endocrinol. Metab. 292 (4): E1166–72.
- ^ The Influence of Catechin on the Antifungal Effect of Amphotericin B against Candida albicans. Ide Mikio, Nihon University Journal of Oral Science, Vol. 26; No.1; Pages 26-31 (2000)
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- ^ catechin on Comparative Toxicogenomics Database
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- ^ Catechin interactions with genes
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- ^ Histamine and acute haemorrhagic lesions in rat gastric mucosa: Prevention of stress ulcer formation by (+)-catechin, an inhibitor of specific histidine decarboxylase in vitro. H. -J. Reimann, W. Lorenz, M. Fischer, R. Frölich, H. -J. Meyer and A. Schmal, Inflammation Research, Volume 7, Number 1 / march 1977, Pages 69-73, DOI 10.1007/BF01964883
- ^ Secondary Metabolites and Allelopathy in Plant Invasions: A Case Study of Centaurea maculosa. Amanda K. Broz and Jorge M. Vivanco, 2006
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- ^ (+)-Catechin acts as an infection-inhibiting factor in strawberry leaf. Yamamoto M., Nakatsuka S., Otani H., Kohmoto K. and Nishimura S., Phytopathology, 2000, vol. 90, no6, pp. 595-600
- ^ Epicatechin and catechin may prevent coffee berry disease by inhibition of appressorial melanization of Colletotrichum kahawae. Zhenjia Chen, Jingsi Liang, Changhe Zhang and Carlos J. Rodrigues Jr, Biotechnology Letters, Volume 28, Number 20 / octobre 2006, Pages 1637-1640, DOI 10.1007/s10529-006-9135-2
- ^ Mechanism of formaldehyde adsorption of (+)-catechin. Toshiyuki Takano, Tomomi Murakami, Hiroshi Kamitakahara and Fumiaki Nakatsubo, Journal of Wood Science, Volume 54, Number 4 / august 2008, Pages 329-331, DOI 10.1007/s10086-008-0946-8
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