Green Tea

Major therapeutic interest

• Enhancing cognitive functions, boosting the central nervous system.

Other therapeutic interest / Traditional Use

• Used as an antioxidant (antioxidants neutralize free radicals caused by pollution, poor diet, overmedication, stress, etc., which are responsible for numerous disorders including circulatory or articulation problems, aging skin, etc.);
• Used for weight control (weight-loss effect);
• Preventing cardiovascular diseases: preventive treatment of atherosclerosis;
• Lowering bad cholesterol (LDL) and triglyceride levels;
• Treating hypotension;
• Reducing the risks of developing Parkinson’s disease;
• Preventing cancers (ovarian, colon, stomach, skin, breast, prostate, pancreatic, bladder);
• Preventing dental cavities and gum disease;
• Reducing the size of precancerous oral lesions (leukoplakia);
• Supporting the immune system;
• Treating diarrhea;
• Treating sunburn (topical application);
• Preventing osteoporosis by increasing bone density.

Cons-indications

• Cardiovascular disorders, hypertension;
• Kidney failure;
• Hyperthyroidism;
• Psychiatric disorders;
• Glaucoma;
• Anemia;
• Bleeding disorders;
• Osteoporosis (if already developed): possible calcium loss;
• Liver disease;
• Hyperacidity;
• Pregnancy and breastfeeding;
• Children 12 and under;
• Diabetes: Use carefully, with closely monitored blood glucose levels.

Drug Interactions

Known human interactions

• Reduces the anticoagulant effect of Coumadin (this is due to the coagulating effect of its vitamin K content. It should be noted that green tea contains substances that counteract the effects of vitamin K and thus have an anticoagulant effect: See below for theoretical effects);
• Reduces effect of Adenocard;
• Increases tremors associated with lithium in cases of abrupt caffeine withdrawal (Carbolith, Lithane, etc.);
• Heightens the adverse effects of ephedrine and ephedrine derivatives (synephrine, phenylephrine). May cause hypertensive crises (Benylin, Dimetapp, DM Decongestant, Dristan, Neo Citran, Sudafed, etc.);
• Reduces the sedative effects of medications that affect the central nervous system (Ativan, Lectopam, Oxazepam, Valium, Xanax [Alprazolam], barbiturates, etc.)

Known animal interactions

• May increase the effect of certain antidepressants and thus increase the effect of Nardil, Parnate, etc. (monoamine oxydase inhibitors [MAOI]); may cause hypertensive crises.

Suspected interactions

• May heighten the side effects of Cipro, Norfloxacin (Noroxin), and other quinolone antibiotics due to the caffeine in green tea;
• May increase the adverse effects of Rilutek when taken concomitantly due to the caffeine in green tea;
• May heighten the primary and side effects of theophylline when used concomitantly due to the caffeine in green tea;
• Oral contraceptives (Alesse, Diane-35, Marvelon, Min-Ovral, Ortho 0.5/35, Triphasil, etc.) may heighten the stimulating effects and side effects of the caffeine in green tea;
• May enhance the effect of anticoagulant/antithrombotic drugs (Coumadin, Lovenox, heparin, etc.), antiplatelet drugs (Plavix, Ticlid) and of salicylic acid derivatives (acetylsalicylic acid [ASA], aspirin, Entrophen, etc.) and other nonsteroidal anti-inflammatory drugs (NSAIDs) (Voltaren, Ibuprofen [Advil, Motrin], Naprosyn, etc.);
• Cimetidine may heighten the stimulating effects and side effects of the caffeine in green tea;
• Bricanyl, Ventolin, etc. (beta-adrenergic agonists) may heighten the cardiac effects (increased heart rate and contractility) of the caffeine in green tea;
• Luvox may heighten the side effects associated with the caffeine in green tea;
• Osoptin (Verapamil), may heighten the stimulating effects and side effects of the caffeine in green tea;
• May inhibit the effects of certain antipsychotic medications (Haloperidol, Largactil, Stemetil, Thioridazine);
• May heighten the toxic effects of Clozaril due to the caffeine in green tea;
• May decrease the vasodilating effect of Persantine and Aggrenox;
• May heighten the hepatotoxic effects in medications that are particularly toxic to the liver (Actos, Avandia, Prandase, Cordarone, Lipitor, Lescol, Mevacor, Pravachol, Zocor, Imuran, Norvir, Viramune, Tegretol, Tylenol, Voltaren, Lamisil, Sporanox, Nizoral, Tamofen, etc.);
• With sedatives that affect the central nervous system (Ativan, Lectopam, Oxazepam, Valium, Xanax [Alprazolam], barbiturates, etc.), the effects of green tea may decrease;
• Modifies blood glucose levels, and thus may alter the effects of insulin and oral diabetes medications (Actos, Diamicron, Avandia, Glucophage, etc.);
• May decrease iron absorption;
• Heightens the effects of nicotine on the central nervous system;
• Alcohol may heighten the side effects of the caffeine in green tea.

Parts used

Leaves and buds (fresh or dried)

Main constituents

• Polyphenols (GTP; green tea polyphenols): flavonoids (theaflavin), tannins, catechin (epicatechin, epigallacatechin, gallocatechin, etc.), proanthocyanidols (theasinensine), alcaloids (caffeine, theophylline, theobromine).

Other names

Camellia sinensis, Thea sinensis