Most of the beneficial effects of green tea are attributed to its polyphenols, mainly catechins and catechin derivatives, including (−)-epigallocatechin-3-gallate (EGCG), epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG) and (−)-gallocatechin gallate (GCG) ( Wang, Provan, & Helliwell, 2003).