Today, almost all people know "green tea is good for health." However, how much do you really know about tea? Green tea leaves consist of 20-30% water-soluble contents and 70-80% water-insoluble contents. Here is more detail about the components.

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Water-soluble contents in leaves (20-30%)

Component Contained Amount Possible Health Benefits Catechin 11-17 % Anti-oxidation, Anti-mutation, Anti-cancer, Hypocholesterolemic effect, Hypotensive effect, Hypoglycemic activity, Platelet aggregation inhibition action, Anti-bacterial activity, Anti-cavity-causing bacterium activity, Antiviral activity, Ant-allergic effect, Deodorant, etc Caffeine 1.6-3.5 % CNS stimulation, sleep-averting effect, Cardiac action, Diuretic action, Metabolic stimulation Theanine 0.6-2.0 % Neuromodulatory action, Relaxing effect, Minimize the caffeine effect Flavonol 0.6 % Reinforcing capillary resistibility, Anti-oxidation, Anti-cancer, Prevent cardiovascular disease, Deodorant Complex Polysaccharide 0.6 % Hypoglycemic effect Vitamin C (Ascorbic Acid) 0.3-0.5 % Anti-scorbutic effect, Anti-oxidation, Anti-cancer, Cold prevention, Cataract prevention, Enhance immune function r-amino acid (GABA) 0.01% Hypotensive activity, Neuromodulatory action Saponin 0.2 % Anti-asthma effect, Anti-bacterial activity, Hypotensive activity Vitamin B 1.2 mg% Prevent perleche and dermatitis, Hypo-lipoperoxidative effect Dietary Fiber 3-7 % Anti-cancer (colon cancer), Hypoglycemic effect Minerals 1.0-1.5 % Zinc: Prevent taste abnormality, Prevent suppression of immune system, Prevent dermatitis Fluorine: Cavity prevention Manganese, Copper, Zinc, Selenium: Anti-oxidationKalium: Keep ion balance

(Note: Health benefits listed are NOT guaranteed, these are possibilities based on recent studies.)

Insoluble contents in leaves (70-80%)

Component Contained Amount Possible of Health Benefits Dietary Fiber 30-44 % Anti-cancer (colon cancer), Hypoglycemic effect Protein 24-31 % Building and repairing body Fat 3.4-4.0 % Cell component, Energy source Chlorophyll 0.6-1.0 % Deodorant Vitamin E 0.02-0.07 % Cythemolysis Prevention, Hypo-lipoperoxidative effect, Anti-cancer, Anti-diabetic effect, Blood circulation promotion, Cataract Prevention, Improve immune function Coenzyme Q-10 0.01 % Forestall aging, Beautiful skin effect β-carotene 0.02 % Anti-oxidation, Anti-cancer, Enhance immune function, Produces Vitamin A Minerals 4-5 % Manganese, Copper, Zinc, Selenium: Anti-oxidation Flavor Component 1-2 mg% Aroma-therapy effect

Partially quoted from:
Keiichiro Muramatsu, "Function of Tea," Japan Scientific Societies Press, March 2002

Reference:
Nihoncha (Japanese Tea), Instructor Text Book 2, p75, May 2007, Nihoncha Instructor Association