role of green tea catechins in various pathological diseases

1. Pharmacological mechanisms
& Clinical Applications Of
Catechins From Green Tea
Guided By
Dr.VGM Naidu
Presented By
Anjana Sharma
PC/2014/201

2. Contents
1. Introduction
2.Catechins
3.What causes Cancer
4.Cellular signalling in Cancer
5.Mechanism Of action of EGCG
6.EGCG as Anticancer agent
7. Role of EGCG in Arthritis
8. Role of EGCG in Obesity
9.Role of EGCG in Diabetic Nephropathy
10.Conclusion
11.References
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3. Introduction
Botanical Name-Camellia sinensis
Origin –China
Chemical Constituents-Catechins,Caffeine,vitamin E and
C,Fluoride and Potassium
Companies producing green tea in india
1.Assamica Agro
2.Tetley GreenTea
The secret of green tea lies in the fact that it is rich in catechins particularly EGCG
(epigallocatechin)
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4. Catechins
▪ Catechins are a type of antioxidant found in the greatest abundance in the leaves
of the tea plant Camellia sinensis
Types of Catechins found in Green tea
1.Epicatechin
2.Epigallocatechin
3.Epicatechin gallate
4.Epigallocatechin -3-gallate
EGCG consists of more than 40 % of total catechins found in green tea and is a
very powerful antioxidant.
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5. Chemical Structure Of Catechins
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6. What Causes CANCER
▪ Tumorigenesis is a multistep process that can be activated by any of various
environmental carcinogens,tumor promoters and inflammatory agents.
▪ Cancer promoting agents modulate the transcription factors (NFκB,AP-1)
,antiapoptotic proteins, proapoptotic proteins,protein kinases,cell cycle proteins
etc.
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7. Cellular Signalling In Cancer
Exposure of cells
specially DNA with
carcinogen leads to
genotoxic damage
• INITIATION
Actively proliferating
abnormal cells persists
and replicates
• PROMOTION
An uncontrolled growth
of cells,gradual
conversion of pre
malignant to malignant
cells.metastasis and
angiogenesis
• PROGRESSION
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8. Mechanism Of Action Of EGCG
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9. Action Of EGCG
▪ Anticarcinogenic Activity
EGCG inhibits cancer-associated stages and exert an inhibitory effect on DNA
methylation via blocking performance of DNMTs, strong free radical scavenging
and antioxidant activities
EGCG exhibits the highest protection against DNA scissions, mutations, and in
non-enzymatic interception of superoxide anions.
EGCG has antiproliferative activities on tumor cells through the blockage of
growth factor binding to the receptor and the suppression of mitogenic signal
transduction
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10. Inhibition of tumorigenesis and possible
mechanism:Molecular targets
1. Antioxidant Potential
The antioxidant activities of EGCG are due to the presence of
phenolic groups that are sensitive to oxidation and can generate
quinone.
Inhibition of oxidative damage constitutes the first line of
defense system against carcinogenic insults and can be
considered as most effective way for preventing cancer.
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13. 2. Induction of Apoptosis and Cell Cycle Arrest
At molecular basis apoptosis can be mediated by two pathways
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14. Contd….
NFκB in cancer cells appears to involve regulation of cell proliferation, control of
apoptosis, promotion of angiogenesis, and stimulation of invasion/metastasis
EGCG-induced apoptosis in tumor cells may be mediated through NFκB
inactivation
This inactivation is associated with the enhancement phosphorylation dependent
degradation of IkBα, subsequent increases in nuclear translocation of p65 protein
and inhibition of IKK activity
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18. Inhibition of epigenetic modifications
▪ Epigenetics refers to heritable changes that are not encoded in the DNA
sequence itself, but play an important role in the control of gene expression. In
mammals, epigenetic mechanisms include changes in DNA methylation, histone
modifications and non-coding RNAs.
Hypermethylation often limits the accessibility of transcription factors to
promoters, promote the methyl-CpG binding domain (MBD) binding, which
results in recruitment of additional silencing-associated proteins, and ultimately,
gene silencing.
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20. Possible modulation of miRNA expression
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21. Role of EGCG in collagen induced Arthritis
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22. Results
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23. EGCG as Anti-Obesity Agent
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25. Role of EGCG in Streptozocin induced Diabetic
nephropathy
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26. Results
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27. Conclusion
Epigallocatechin-3-gallate (EGCG) is a potent antioxidant,
antiinflammatory, antiangiogenic, and antioncogenic compound
derived from green tea.
Most modern medicines currently available for treating
cancers are very expensive, toxic, and less effective in treating the
disease.Thus, one must investigate further in detail the EGCG derived
from green tea, described traditionally, for the prevention and
treatment of cancer and other diseases.
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28. References
1. Singh, Brahma N., Sharmila Shankar, and Rakesh K. Srivastava. "Green tea catechin,
epigallocatechin-3-gallate (EGCG): mechanisms, perspectives and clinical applications." Biochemical
pharmacology 82.12 (2011): 1807-1821.
2. Xu,Yan, et al. "The anti-obesity effect of green tea polysaccharides, polyphenols and caffeine in
rats fed with a high-fat diet." Food & function 6.1 (2015): 296-303.
3.Yoon, Sang Pil, et al. "Protective effects of epigallocatechin gallate (EGCG) on streptozotocin-
induced diabetic nephropathy in mice." Acta histochemica 116.8 (2014): 1210-1215.
4. Gu, Jian-Wei, et al. "EGCG, a major green tea catechin suppresses breast tumor angiogenesis and
growth via inhibiting the activation of HIF-1α and NFκB, andVEGF expression." Vasc Cell 5.1 (2013):
5. Shimizu, Masahito, et al. "Chemopreventive Potential of GreenTea Catechins in Hepatocellular
Carcinoma." International journal of molecular sciences 16.3 (2015): 6124-6139.
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