Does Green Tea increase Longevity?
09/25/09
Green tea has:
  • polyphenols
  • catechins (more specifically epigallocatechin gallate)
  • carotenoids
  • tocopherols
  • ascorbic acid
  • chromium
  • manganese
  • selenium
  • zinc
source: wikipedia.com
interesting articles via web of science link:
Polyphenolic Chemistry of Tea and Coffee: A Century of Progress
Green tea and bone metabolism
Green tea consumption and gastric cancer in Japanese: a pooled analysis of six cohort studies

Inhibitory effects of epigallocatechin-3 gallate, a polyphenol in green tea, on tumor-associated endothelial cells and endothelial progenitor cells

My plan right now is to:
-find an article supporting the wikipedia page claims [Excellent start - also try substructure searches for some of your compounds]
-if confirmed, look at the beneficial aspects of each compound and write about each.

10/01/2009
Following further research, I found that polyphenols, more specifically catechins, are the most active in contributing to what people attribute to the 'health benefits' of green tea. Because of this, i am narrowing my topic down to Catechins and my title might be something like: 'Catechins: green tea the key to life' or something to that effect.

Active catechins include:
"catechin, gallaocatechin, epicatechin, epigallocatechin, and Epigallocatechin gallate (also known as EGCG)"
source: http://www.umm.edu/altmed/articles/green-tea-000255.htm

Other possible sources for the potency of green tea include:
http://news.bbc.co.uk/2/hi/health/7947620.stm
http://www.sciencedaily.com/releases/2003/08/030805072109.htm
[You'll have to get the primary sources for these - if you have trouble consider emailing the researchers JCB]

10/06/2009

Note: I am focusing my paper on EGCG and its substructure

Following a Scifinder substructure search i found the following (6) substructures:
Structural Isomers
CAS:4233-96-9, 19065-20-4, 5127-64-0, 4233-96-9, 989-51-5
EGCG is part of the following strucutre
CAS: 86588-88-7
[can you link to their ChemSpider entries? JCB]

As there seem to be a lot of structural isomers i will concentrate on these.

This means that my topic encompass the following:
  • background on why EGCG is so important
  • The structural Isomers of EGCG and their potency as compared to EGCG.
Come to think of it, i would akin my research paper to a SAR (Structure activity relationship) search [if you want to focus on QSAR, you might find a few studies - they will be linked to specific assays JCB]
In class 10/15/2009
Notes:
formatting problems solved via notebook, install drexel cisco vpn, no posting copywritten pdf
how to do doi:
look for link with doi, right click-> copy link
Inter library loan.
bullet is done by # followed by a space

Found an interesting article about EGCG curing colon cancer. Will probably use this to establish the potency of the substance as opposed to direct evidence with SAR etc.
EGCG against colon cancer (scifinder)

Assignments

  1. Write a summary of one of the articles you are reading for your project paragraph by paragraph. One or two sentences per paragraph is fine. You must do this in your own words. No significant amount of text can be copied from the abstract or any part of the paper. Either put the summary in bullet form on your research log or on AcaWiki. Due October 29, 2009 20:50 PM
  2. Answer one of the FAQ questions or create and answer an FAQ question relating to a topic relating to chemistry publishing. You must provide at least one relevant reference. You must summarize in your own words - copying text from anywhere verbatim is not allowed. Due October 29, 2009 20:50 PM

10/18/2009

Assignment 1 answer EGCG against colon cancer (source)

[Full Marks JCB]
Title:
'Suppression of Met activation in human colon cancer cells treated with (−)-epigallocatechin-3-gallate: Minor role of hydrogen peroxide'
Abstract:
EGCG is known to suppress breast cancer via suppression of 'Met' activator (the receptor of Hepatocyte Growth Factor aka. HGF). Met over expression is one of the leading causes of colon cancer. It was never analyzed whether or not it is EGCG or H2O2 (a product which is made when EGCG is added to a cell culture) was suppressing the Met activation. It was concluded that Met activator suppression happens with or without H2O2 thus EGCG may be therapeutic against colon cancer.

Introduction:
Paragraph 1:
Colorectal cancer is the number two cause of cancer related deaths. The survival of cancer patients who shows metastatic is less than 10%. It is known that the activation of the Met receptor causes metastasis as its activation with its ligand HGF induces symptoms which are crucial for metastasis.
Paragraph 2:
Polyphenols in green tea (EGCG) has been known to suppress cancer related pathways in vitro and in vivo. But the effect of EGCG has not been studied in depth in relation to the Met receptor and since EGCG accumulates naturally in the intestines it is a promising area of study for the prevention of colon cancer deaths related to metastasis.
Paragraph 3:
H2O2 is produced whenever EGCG is added to cell cultures thus Met suppression cannot be attributed to EGCG with 100% certainty. This study will confirm whether or not EGCG alone can suppress the Met receptors.

Materials and Methods:

Cell Culture
  • Cancer cell cultures HCT116 and HT29 were obtained.
EGCG/HGF cell treatment
  • Cells were plated in 60mm dishes and grown without serum for 48h.
  • Cells were incubated for 4h in media with serum.
  • After serum starvation, pretreatment with varying concentrations of EGCG followed with 30 ng/mL HGF. (sometimes 30U/mL catalase was added depending on the experiment).
  • After serum starvation, cells were pretreated for 30 min with various concentrations of EGCG (Sigma–Aldrich, St. Louis, MO) followed by treatment with 30 ng/ml HGF (Calbiochem, San Diego, CA). In some experiments, 30 U/ml catalase (Roche Applied Science, Indianapolis, IN) were added to the media 10 min prior to addition of EGCG.
H2O2 cell treatment
  • Cells were plated in serum for 48h then incubated without serum for 4h. H2O2 was then added and the sample was incubated further for 30mins.
Western blotting
  • Standard western blotting was conducted*
H2O2 measurement
  • Serum starved cells were incubated with various amounts of EGCG in invitrogen for 30 min.
  • samples of media were analyzed using Red Hydrogen Peroxide/Peroxidase Amplex assay Kit.
Enzyme-linked immunosorbent assay (ELISA)
  • Pretreatment with presence or absence of previously mentioned catalase
  • EGCG added to media and samples were incubated for 30 mins.
  • Addition of 30ng/mL HGF was then added.
  • Cells were incubated for 15minutes more and lysed in RIPA buffer with inhibitors.
  • ELISA kit Used
Cell Viability
  • HCT116 cells were incubated with various H2O2 for 15 min.
  • Cells then stained with Guava Viacount for 5 mins.
  • Percentage viable cells was calculated using Guava Viacount assay on a Guava Personal Cytometer

Results:
Paragraph 1:
To test whether EGCG suppresses Met activation 'HCT116 and HT29 cells where pre-incubated with various concentration of EGCG for 30 min, followed by the addition of HGF to the media'. When there was no EGCG the levels of p-Met in both HCT116 and HT29 increased. With EGCG concentration as low as 0.5μM p-met was suppress in both cell lines which was visualized by immunoblots.
Paragraph 2:
H2O2 produced 'after incubating v arious concentration of EGCG in cell culture media for 30 min.' With no EGCG approximately 0.1 and 0.25μM H2O2 was found in both cell lines. Although the amount of H2O2 increased with increasing amounts of EGCG which maxed out at 1μM added to the cell culture the concentration of H2O2 never exceeded 1μM.
Paragraph 3:
Various concentrations of H2O2 was incubated with cell cultures and at less than 2.5μM Met phosphorylation was not affected.
Paragraph 4:
At less than 100μM concentration of H2O2 the viability of HCT116 cells was not affected the concentration needed to be brought up to 500-1000μM to have any affect on the viability of the cells.
Paragraph 5:
EGCG performance was unaffected by Catalase presence thus it can be concluded that Met suppression by EGCG is independent of H2O2 presence.

Discussion:
Paragraph 1:
At 0.5μM EGCG concentration, human physiological range, EGCG suppressed Met activation.
Paragraph 2:
At 10μM EGCG concentration not enough H2O2 was created to have an effect on Met phosphorylation.
Paragraph 3:
Concentrations of 500μM H2O2 has been found to affect the viability of lung cancer cells. It was also discovered in this study that concentrations of 500μM and 1000μM affect viability of colon cancer cancer cells. Also, catalase has no effect on EGCG performance.
Paragraph 4:
It is concluded that EGCG, at physiological range concentrations (1-10μM) does not produces enough H2O2 to affect its inhibition of met receptors. The possible effect of H2O2 was ruled out by the use of catalase and by quantitatively analyzing the amount of H2O2 needed to be effective.

End Assignment


Change topic! well probably more specified rather than changed.... 'Effect of EGCG and its various isomers on Met phosphorylation' is this too specific? I chose met phosphorylation because it seems to be what EGCG does to cancer cells to prevent cancer related deaths.

[that sounds very reasonable JCB]

OK.. i think i jumped the gun a bit with my previous topic and i know now, even though it may be a bit later than i would like, that the word 'isomers' in my topic gives too broad a topic while the idea of having them act as anti MET phosphorylators is too specific and hard to make an exhaustive search for. Because of this, i want to change the focus with a specific substructure of EGCG rather than ALL the isomers which exist.
[Feel free to change your exact focus right up to the end - you will know more as you start writing JCB]

Hm... as of now i think a good topic is 3-O-acyl derivatives of EGCG and their anticancer activity (or pharmaceutical implications... doesnt have to be anticancer if i cant find enough sources)

Papers that i will use for the project:
EGCG against colon cancer (source)
Cancer Prevention wi th Green Tea Polyphenols for the General Population,and for Patients Following Cancer Treatment
Enhanced antitumor activities of (−)-epigallocatechin-3-O-gallate fatty acid monoester derivatives in vitro and in vivo
Anticancer activity of 3-O-acyl and alkyl-(−)-epicatechin derivatives
Tumor Chemopreventive Activity of 3-O-Acylated-epigallocatechins
Design, Semisynthesis, and Evaluation of O-Acyl Derivatives of (−)-Epigallocatechin-3-gallate as Antitumor Agents
Outline:
Intro:
-History of green tea (sh ort background)
-polyphenols in general
-mention of 6 main isomers (non-exhaustive) and papers that have been done on them.
-Cancer (Met Phosphorylation)
Body:
-EGCG
-

Conclusion:
-Preliminary results show that EGCG prevents met phosphorylation. Not enough information as of now about the other isomers.

Assignment 3
[Full Marks JCB]

5 properties of EGCG

Solubility in water:
- Clear colourless solution at 5mg/mL (5g/L) (Report) NIH.gov (Source)
- 3.6mg/mL (3.6g/L) at 25C

- 5.12 +/- 2.21 mM (2.346 g/L) Moon (Source)
- 5 mg/mL (5g/L) presents a clear colourless solution (Herbs-Tech) Source
- 32.77 mg/L (predicted) (0.0327 g/L) (Chemspider)Source[Where is that number on the ChemSpider page? JCB]
- 521.7 g/L (521.7mg/mL) Kwang(Paper) Source

Melting point:
- 218 C Merck Index

- 217 C

- 140-142 C Source
EGCGmpCNC.jpg
- 218 C (Product Spec.) Source
- 254 C (TEA: bioactivity and therapeutic potential by Zhen) Source

pKa
- 7.75 (Slobodan) Source
- 7.59-7.75 (Nakagawa) Source
- 7.55 (Inoue) Source
- 7.59-7.75 (Kumamoto) Source
- 7.55 (Proniuk) Source

Oral dosing Mice LD50
- 2170mg/kg (Herbs tech) Source
- 2170 mg/kg (NIH) Source
- 2170 mg/kg Chemspider MSDS
- 1248-1647mg/kg (Hara) Source
- 2170mg/kg (Dudka) Source


Stability**
- stable but may be light sensitive (Chem Spider) Source
- stable but may be light sensitive (Chemical Book) Source
- no significant degradation after 8 weeks (Labbe) Source
- addition of glycerine to BHT is the most stable medium for storage (Proniuk) Source
- stable (MSDS) Source

DONE