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Epigallocatechin-3-gallate

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Epigallocatechin-3-gallate

"EGCG" redirects here. For the software, see Extended GCG.
Epigallocatechin gallate
Identifiers
CAS number 989-51-5 N
PubChem 65064
ChemSpider 58575 YesY
MeSH Epigallocatechin+gallate
ChEBI CHEBI:4806 YesY
Jmol-3D images Image 1
Properties
Molecular formula C22H18O11
Molar mass 458.37 g mol−1
Appearance
Solubility in water soluble[1]
Solubility soluble in ethanol, DMSO, dimethyl formamide[1] at about 20 g/l[2]
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin.

EGCG is the most abundant catechin in tea and is a potent antioxidant that may have therapeutic applications in the treatment of many disorders (e.g. cancer). It is found in green tea, but not black tea; during black tea production, the catechins are converted to theaflavins and thearubigins.[3] It is also found in various vegetables, nuts, as well as carob powder at 109 mg per 100g.[4] In a high temperature environment, an epimerization change is more likely to occur; however as exposure to boiling water for 30 straight minutes leads to only a 12.4% reduction in the total amount of EGCG, the amount lost in a brief exposure is insignificant. In fact, even when special conditions were used to create temperatures well above that of boiling water, the amount lost increased only slightly.[5]

EGCG can be found in many supplements.

Pharmacology

EGCG is an inhibitor of the enzymes:

and antagonises the Epidermal growth factor receptor 1 and Epidermal growth factor receptor 2.[11]

Research on potential therapeutic uses

EGCG has been the subject of a number of studies investigating its potential use as a therapeutic for a broad range of disorders:

HIV

A large amount of research has been conducted investigating the benefit of EGCG from green tea in the treatment of HIV infection, where EGCG has been shown to reduce plaques related to AIDS-related dementia in the laboratory, as well as block gp120.[12][13][14] However, these effects have yet to be confirmed in live human trials, and it does not imply that green tea will cure or block HIV infection, but it may help regulate viral load as long as it is not involved in adverse drug reactions. The concentrations of EGCG used in the studies could not be reached by drinking green tea. More study into EGCG and HIV is currently underway.[15]

Cancer

There is increasing evidence to show that EGCG – along with other flavonoids – can be beneficial in treating brain,[16] prostate,[17][18] cervical[19] and bladder[20] cancers. EGCG has been shown to bind and inhibit the anti-apoptotic protein Bcl-xl,[21] which has been implicated in both cancer cell and normal cell survival.[22]

Chronic fatigue syndrome

Research at Panjab University Chandigarh found that EGCG is effective in various mouse models of chronic fatigue syndrome.[23][24][25]

Sjögren's syndrome

Research at Medical College of Georgia found that EGCG was effective in a mouse model of Sjögren's syndrome.[26]

Endometriosis

Xu et al. found that EGCG reduce lesion size in a mouse model of endometriosis.[27]

Spinal muscular atrophy

Sakla and Lorson found that EGCG increases the number of SMN transcripts in spinal muscular atrophy cells, most probably through modulation of alternative splicing.[28]

Neurodegeneration

EGCG is a natural chelator and has been shown to reduce iron-accumulation in instances of neurodegenerative diseases like dementia, Alzheimer's, and Parkinson's.[29] Parc de Salut Mar and Instituto Hospital del Mar de Investigaciones Médicas in Spain are conducting a clinical trial of EGCG as a potential treatment for intellectual impairment in people with Down Syndrome and Fragile X[30]

Cannabinoid 1 receptor, CB1 receptor Activity

EGCG has a binding affinity of Ki=33.6μM towards the first cannabinoid receptor, CB1.[31]

Periapical lesions

There are in vitro data about theurapeutic potential of EGCG in periapical periodontitis.[32]

Drug interactions

A study using mouse models at the University of Southern California showed that, in contrast to the myriad benefits commonly associated with green tea and green tea extract (GTE), EGCG binds with the anti-cancer drug Velcade, significantly reducing its bioavailability and thereby rendering it therapeutically useless.[33] Schönthal, who headed the study, suggests that consumption of green tea and GTE products be strongly contraindicated for patients undergoing treatment for multiple myeloma and mantle cell lymphoma.[33] EGCG may reduce the bioavailability of the drug sunitinib when they are taken together.[34] EGCG was also found to induce apoptosis in endometrial carcinoma cell line (Ishikawa cells and human primary endometrial carcinoma cells) via ROS generation and p-38 activation.2012 Manohar et al., J Nutr Biochem. 2012 Sep 5 [Epub ahead of print]

Carcinogenic potential

EGCG was, among other tea polyphenols, found to be a strong topoisomerase inhibitor, similar to some chemotherapeutic anticancer drugs, for example, etoposide and doxorubicin.[35][36][37][38][39] This property might be responsible for observed anticarcinogenic effects; however, there is also a carcinogenic potential. High intake of polyphenolic compounds during pregnancy is suspected to increase risk of neonatal leukemia. Bioflavonoid supplements should not be used by pregnant women.[40][41][42] Maternal consumption of tea or coffee during pregnancy may elevate the risk of childhood malignant central nervous system (CNS) tumours through unknown mechanisms.[43]

Spectral data

UV-Vis
Retention time 34.5 min (C18 RP, Acetonitrile 80%)
Lambda-max 274 and 240 nm (see picture)
Extinction coefficient
IR
Major absorption bands cm−1
NMR
Proton NMR


(500 MHz, CD3OD):
d : doublet, dd : doublet of doublets,
m : multiplet, s : singlet

δ :
Carbon-13 NMR
Other NMR data
MS
Masses of
main fragments
ESI-MS [M+H]+ m/z : 459

See also

References

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