Green tea molecule. Molecular model of a molecule of epigallocatechin gallate (EGCG), a polyphenol flavonoid extracted from green tea with powerful antioxidant properties. The atoms are shown as spheres and are colour coded: carbon (yellow), hydrogen (white) and oxygen (red). EGCG has been shown to inhibit the growth of human cancer cells. It targets an enzyme (dihydrofolate reductase) that plays an important role in the production of DNA and which is targeted by other anti-cancer drugs. As it targets a step in DNA production it tends to kill only growing cells, the majority of which will be cancerous cells. However, it binds to the enzyme less tightly than current drugs and so may cause fewer side effects.