Scientific Name/Common Name: Camellia sinensis / Green tea
Part(s) Used: Leaf (young, dried, non-fermented)
Constituents/Active Ingredients: Green tea is rich in the flavanol group of polyphenols known as catechins (up to 30% of the dry leaf weight). Other polyphenols include flavanols and their glycosides, such as chlorogenic acid, coumarylquinic acid, and one unique to tea, theogallin (3-galloylquinic acid). Caffeine is present at an average level of 3% along with very small amounts of the other common xanthines, theobromine and theophylline. The amino acid theanine (5-N-ethylglutamine) is also unique to tea.
Overview: Green tea is native to Asia. Green tea is taken from the same plant as black tea, the only difference being that green tea is not fermented during the drying process. Tea was introduced to Europe in the sixteenth century and its use was commonplace by the seventeenth. Green tea generally comes from China and Japan and black tea from India and Africa. Green tea is often recommended for diarrhea and indigestion. It is high in caffeine and tannins and acts as both a stimulant and anti-diarrheic. Green tea has traditionally been recommended for heart health maintenance, chest pain relief, dizziness, hemorrhoids, ulcers, headache, and drowsiness. More recently, green tea extracts have been produced that often have 136-300 mg (-)-epigallocatechin-3-gallate (EGCG) and 75-150 mg caffeine.
Traditional Use/Benefits/Body Systems: Traditionally the tea has been taken as a stimulant, to alleviate diarrhea and indigestion, and for cardiovascular health. Green tea extracts are used as a concentrated source of antioxidants, for energy/alertness, and for weight management.
Clinical Studies/Scientific Research/References:
Chantre P, Lairon D. Recent findings of green tea extract AR25 (Exolise) and its activity for the treatment of obesity. Phytomedicine 2002;9(1):3-8.
Coimbra S, Castro E, Rocha-Pereira P, Rebelo I, Rocha S, Santos-Silva A. The effect of green tea in oxidative stress. Clinical Nutrition 2006;25(5):790-796.
Wichtl M and NG Bisset (eds). 1994. Theae nigrae folium – Black Tea. In Herbal Drugs and Phyto-pharmaceuticals. (English translation by Norman Grainger Bisset). CRC Press, Stuttgart, Pp. 490-492.
Disclaimer: This information in our Herbal Encyclopedia is intended only as a general reference for educational purposes. It is not a replacement for medical advice. This content does not provide dosage information, cautions/contraindications, or possible interactions with prescription drugs. Please consult any relevant product labels for detailed information on use and with a medical practitioner for individual health advice.