Dear Tea Sippers, Thank you for the positive feedback on my recent What’s Healthy About Tea posts that focus on the vocabulary of tea and health research. You inspire me to continue this thread with Epigallocatechin gallate, most commonly written as ECGC. This is one of compounds found in true tea, Camellia sinensis, being studied by research organizations all over the world and with regard to many different health issues.

Babette Donaldson 

Epigallocatechin gallate

  Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin. EGCG, the most abundant catechin in tea, is a polyphenol under basic research for its potential to affect human health and disease.    (Wikipedia)
 
  What is ECGC? One of the confusing thing when discussing the cellular makeup of the tea leaf is that so many of the elements fall into more than one category. EGCG is an excellent example. It is an organic compound of epigallocatechin and gallic acid It is a secondary metabolite.  Secondary metabolites are organic compounds that are not involved with the growth or reproduction of the organism and are not absolutely necessary for survival though, as in the case of Camellia sinensis, they play a part in the plant’s defense.  It is a catechin. Catechins are polyphenolic compounds with high antioxidant benefits. EGCG is the most abundant catechin in Camellia sinensis.  It is a phenol. A phenol is a naturally occurring compound in the tea plant of which ECGC is only one. They are responsible for aspects of taste and mouth-feel and are being actively researched to better understand their potential benefits for health and how they act in relationship with other compounds in the tea leaf.  It is an antioxidant. Antioxidants help reduce oxidative stress in the body by binding with unstable and destructive free radicals and then helping to neutralize their harmful potential and then eliminate them from the body It is an astringent. An astringent is a naturally occurring compound in many foods that shrink body tissue. In tea, this effect produces the slightly dry mouthfeel but it can also soothe sore and swollen throat tissue. When tea extracts are used in skincare products, it produces a tightening of pores and a refreshing feeling to skin. It is a tannin. A tannin is one of the organically occurring plant compounds that has traditionally been used for tanning and preserving leather We can understand it in many different ways but it is also one of the things that we can actually taste in tea.  The astringency. The mouthfeel. Leads some to assume that, while fresh Camellia sinesis leaves may all contain approximately the same amount of the compound, that processing may change this…   A question we will consider. **

Is ECGC only available in green tea?

Most of the research on ECGC is done on green tea because it contains so much more than other types of tea and also much more than in any other food. The oxidation of black tea results in a greatly reduced amount of ECGC. It is generally assumed that the amount present in green tea is approximately four times greater in green tea. But other teas that are not fully oxidized also contain the compound. This includes white, yellow and oolong, but all with varying amounts. Very small amounts can be found in other foods such as apples, strawberries, raspberries, blackberries, peaches, kiwi, avocado plums, onions, hazelnuts, pecans and in carob.

Can we increase the amount of ECGC by the way we make tea?

The answer is “probably yes”. But you may not want to drink the result. Because the actual flavor of ECGC is bitter, increasing the amount in your cup will probably be unpleasant. The technique would be to use boiling water and then steep green tea leaves for ten minutes or more. This goes against the recommendations for brewing green tea which is to use water that is between 185-195 degrees F, steeping for less than two minutes.

Read More About The Science

Beneficial Effects of Dietary EGCG and Voluntary Exercise on Behavior in an Alzheimer’s Disease Mouse Model

Authors : Jennifer Walker, Diana Klakotskaia, Deepa Ajit, Gary Weisman, W. Gibson Wood, Grace Sun, Peter Serfozo, Agnes Simonyi, Todd Schachtman.   

 Journal of Alzheimer’s Disease, vol. 44, no. 2, pp. 561-572, 2015

Epigallocatechin-3-Gallate (EGCG), a Green Tea Polyphenol, Stimulates Hepatic Autophagy and Lipid Clearance

Authors:  Jin Zhou, Benjamin L. Farah, Rohit A. Sinha, Yajun Wu, Brijesh K. Singh, Boon-Huat Bay, Chung S. Yang, Paul M. Yen Published: journal.pone.0096884