Tea (Camellia sinensis) is a popular, socially accepted, safe and healthy beverage that is widely consumed around the world. Tea is beneficial to prevent and cure a variety of diseases related to oxidative stress (1-3). The health benefits ascribed to the consumption of teas are thought to be associated with their high content of bioactive ingredients such as polyphenols. The latter are secondary plant metabolites and include the subclasses of flavonoids, flavones, flavonols, flavanols, isoflavones, flavanones and anthocyanidins (4).The major active flavonoids in green tea are epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and epigallocatechin gallate (EGCG) (5,6).

The structural features of green tea catechins that significantly contribute to their antioxidant action are the presence/absence of the galloylmoiety and the number and positions of the hydroxyl groups on the rings. The latter determine their ability to interact with biological matter through hydrogen bonding, or electron and hydrogen transfer processes within their antioxidant activities. In fact, the antioxidant mechanism implies hydrogen atom transfer or single electron transfer reactions, or both (7).