Epicatechin gallate (ECG, (−)-epicatechin-3-gallate) is a flavan-3-ol, a type of flavonoid, primarily found in green tea (Camellia sinensis), with smaller amounts in cocoa, grapes, buckwheat, and other plants. It is not a nutrient.

As a polyphenolic catechin, ECG is formed by the esterification of epicatechin with gallic acid. ECG is studied for its ability to reverse methicillin resistance in Staphylococcus aureus, but it has poor bioavailability and thermal instability in boiling water.

Chemical structure and properties

ECG is a flavonoid with a molecular formula of C22H18O10 and a molecular weight of 442.4 g/mol. Its structure comprises a flavan-3-ol backbone (epicatechin) esterified with gallic acid at the 3-position, featuring two catechol rings and a trihydroxybenzoate ring with multiple hydroxyl groups. In test tube experiments, the galloyl moiety enhances ECG's radical scavenging compared to epicatechin, with a DPPH assay showing higher antioxidant activity due to the additional hydroxyl groups. ECG is soluble in water, ethanol, and dimethyl sulfoxide, but degrades significantly in boiling water, limiting its stability in tea preparation.[scientific citation needed]

Tea

ECG is a major catechin in green tea, constituting 5–6% of total catechins, alongside epigallocatechin gallate, epigallocatechin, and epicatechin. Its content is lower in black tea due to oxidation into theaflavins during fermentation.[scientific citation needed]

See also