Green Tea Extract

This chapter reviews the major studies and findings on green tea extract (GTE). It further discusses the potential health benefits that have yet to be substantiated. The tea plant, Camellia sinensis, is most commonly known in three forms: (1) fully fermented black tea; (2) partially fermented oolong tea; and (3) unfermented green tea. Green tea's antioxidant properties are attributed to polyphenolic catechins, also known as flavan-3-ols. Catechins make up about 30–35% of the dry weight of the green tea leaf, and 90% of all polyphenols in green tea. Epigallocatechin-3-gallate (EGCG) is the most potent of the catechins and the active ingredient in green tea and GTE. Studies have demonstrated that topical GTE suppresses metalloproteinase and age-related collagen cross-linking in mice. The optimal concentration, dosage, and route of administration must be determined and substantiated through future studies in order for GTE to reach its full potential as a botanical cosmeceutical.