Epigallocatechin Gallate (EGCG) Is the Most Effective Cancer Preventive Polyphenol in Green Tea
Green tea is a popular drink consumed daily by millions of people around the world. Previous studies have shown that some polyphenol compounds from green tea possess anticancer activities. Researchers from the Tang Center for Herbal Medicine Research at the University of Chicago conducted a systemic evaluation of the ten dominant powerful antioxidants found in green tea to determine their cancer chemopreventive potentials and the relation to their structure and function. They studied the following polyphenols; caffeic acid, gallic acid, catechin, epicatechin, gallocatechin, catechin gallate, gallocatechin gallate, epicatechin gallate, epigallocatechin, and epigallocatechin gallate which is thought to be green teas most valuable component and which is commonly represented as EGCG.
The antioxidants were tested on human colorectal cancer cells known as HCT-116 cells and also SW-480 cells. Among the 10 polyphenols, EGCG showed the most potent antiproliferative effects (growth blocking effects), and significantly induced cell cycle arrest in the G1 phase (blocking the growth of the cancer) and cell apoptosis (causing the death of the cancer).
Both catechin and epicatechin lacked effect and gallic acid had some anticancer effect but when they were bonded as attachments to gallic acid forming catechin gallate and epicatechin gallate the antiproliferative effects were increased significantly. A similar relationship was found between epigallocatechin and epigallocatechin gallate (AKA EGCG) when gallic acid was added to create EGCG the anticancer activity rose significantly. The study is published in the November 2012 issue of the journal Nutrients.