Tea has a history of culinary and medicinal use for the past 50 centuries. It is the second most consumed drink after water.
Tsa is a shrub, about a meter or more high. Branches are smooth. Buds are silky. Leaves are elliptic-oblong, 7.5 to 20 centimeters long, 3.5 to 6 centimeters wide, tapering at either end, with toothed margins. Flowers are white, about 3 centimeters in diameter. Fruit is leathery, 3-celled capsule, each capsule containing a seed. Seeds are nearly spherical, obtusely angled, smooth, pale brown, about 2 centimeters in diameter.
- Introduced shortly before 1905.
- Scattered cultivation in the Baguio area.
- Originally from the triangle of countries of South China, Assam (northeastern India) and Cambodia.
- Planted in almost all tropical and subtropical regions of the world, but especially economically cultivated in China, Japan, India, Sri Lanka and Indonesia.
- Tea leaves, depending on source and fermentation process, yield: caffeine 0.9 to 50/0 caffeine, free or bound with glycosides; 0.05% theobromine; some theophylline; purine derivatives xanthine, methylxanthine, and adenine; tanning agents (tannin, polyphenols, gallic acid, and catechin derivatives), and chlorophyll (in fresh or unfermented leaves).
- Also yields vitamins (A, B2, C, D, P, nicotinic acid), minerals (manganese), and carbohydrates (dextrin, pectin), and essential oils (providing aroma).
- Phytochemical screening of leaves yielded alkaloids, flavonoids, steroids, and tannins. One gram of C. sinensis leaf extract yielded 0.7 gm of phenolic compounds, 14 mg of flavonoid, and 0.11 gram of reducing power. (see study below) (24)
- Phytochemical screening of various extracts yielded flavanoids, glycosides, tannins, phenolic compounds, carbohydrates, amino acids, and proteins. (see study below) (32)
- Natural scent of the tea is from a fragrant volatile oil.
- Essential oil is both euphoriant and calming.
- Stimulant effect of the tea from the caffeine and theobromine and small amounts of alkaloids.
- Considered astringent, cardiotonic, diuretic, expectorant, stimulant.
- Considered nutraceutical, anti-inflammatory, immunostimulatory, insulin-enhancing, chemopreventive, antimicrobial, antihypertensive.
- Fresh leaves contain four to five times more essential oil as dried or fermented leaves.
- Compared to coffee, the stimulant effect of tea's caffeine manifest more slowly and persist longer, as the caffeine from tea must be liberated from tannic and glycosidic bonding.
• Color of Tea:
Green tea, black tea, white tea, yellow tea and pu-erh tea are all derived from the same plant, Camellia sinensis. The differences are the results of processing rather than subspecies used or how it is grown. Varying levels of oxidation changes the color, flavor, and chemistry, even medicinal use. (29) Pu-erh tea is a variety of fermented tea produced in Yunnan province, China. Fermentation involves microbial fermentation and oxidation of the tea leaves. (31)
Edibility / Culinary
- Edible: leave
- Green tea made from steamed and dried leaves; black tea from fermented and dried leaves.
- Tea extracts used for flavoring alcoholic beverages, dairy desserts, candy, baked goods, pastries and puddings.
- Fixed oil from the seeds sometimes used in making margarine.
- Recorded as early in the 6th century as a Chinese herbal medicine, recommended particularly for people who slept too long. It was used to promote blood circulation, promote excretion of alcohol and other harmful substances, invigorate the skin, promote digestion, combat tiredness and depression, among many others. Strong infusions were used as external applications for skin ailments, eruptions, abrasions and athlete's foot.
Decoction of leaves used as stimulant and to relieve fatigue.
- Used to soothe headaches, aid digestion.
- Essential oil from fermented and dried leaves used for perfumery and food flavoring.
- Edible oil made from the seed.
- Residual cake containing saponin are made into little round balls, used by Chinese for washing hair.
- Tea seed oil used in the manufacture of sanctuary or signal oil for burning purposes.
- Dye: A source of varied food colors - black, green orange, yellow.
- Wood: moderately hard, makes into a good walking stick.
- The tea plant is rich in rituals and legends. A monk version of its origin tells of Bodhidhama, a Buddhist disciple, afflicted with sleepiness, easily falling to sleep while meditating. Angered that he could not keep his eye open, he cut off his eyelids and cast them to the ground. On the ground, the first tea plant grew, its leaves resembling the eyelids. The monks noticed the animating power of beverages made from the leaves, and soon, it because a ritual drink before meditation.
• Antioxidant: Tea contains flavonoids with its beneficial antioxidant effects.
• Anti-Diabetic / Decreased Insulin Resistance: Study on the water extract of Thea sinensis suggest the antidiabetic activity is derived, at least in part, from a decrease in plasma insulin, due to decreased insulin resistance. (3) Study showed Camellia sinensis, Momordica charantia, and Cinnamomum species effectively reduced insulin resistance in animal models involving different molecular mechanisms. (33)
• Genital Warts: Polyphenon E®, a proprietary extract of green tea, has been approved in the U.S. for external topical use for genital warts caused by human papilloma virus.
• Cardiovascular Benefits: Early studies suggest that regular intake of green tea may help reduce the risk of heart attacks or atherosclerosis. Further clinical trials are needed before firm recommendations.
• Hypolipidemic: Animal studies and limited human research suggest benefits of green tea on cholesterol and triglyceride levels. (•) In a double-blind crossover study of green tea (Camellia sinensis) in patients with dyslipidemias, a beneficial effect was demonstrated with a significant reduction of total cholesterol (3.9% reduction / p<0.006) and LDL-cholesterol (4.5% reduction / p<0.026). There was no significant influence on HLD-cholesterol, triglycerides, and Apo-B levels. (10)
• Lactose Intolerance: Study results suggest the lactose content of milk was reduced by adding tea extracts and suggests that with milk-related gastrointestinal problems have milk with herbal tea extracts. (5)
• Saponins / Alcohol Absorption and Metabolism: Study showed the seed saponins of T sinensis seem to suppress alcohol absorption by slowing gastric emptying and inhibiting absorption across the cell membranes of the digestive tract. (6)
• Effect on Drug Metabolizing Enzymes: Study on decaffeinated green tea is unlikely to alter the disposition of medications primarily dependent on the CYP2D6 and CYP3A4 pathways of metabolism. (7)
• Antimicrobial: Study of extracts showed the highest % yield with chloroform followed by petroleum ether, methanol and diethyl ether. Organisms inhibited were P aeruginosa, B subtilis, S dysenteria, E coli, Yersinia, S typhi among others. Results indicate tea extracts have promising antibacterial activity, especially for intestinal microorganisms causing diarrhea and dysentery. (8) A methanolic extract of Camelia sinensis leaves showed antimicrobial activity against B. subtilis and Enterococcus sp. (see constituents above) (24)
• Colds and Flu / T Cell Function: Study of a proprietary formulation of Camellia sinensis show it to be a safe and effective dietary supplement for preventing cold and flu symptoms and for enhancing T cell function. (9)
• Inhibitory Effect on Venom Neuromuscular Blockade: Study of Camellia sinensis extract showed an inhibitory effect against the neuromuscular blockade induced by the South American rattlesnake Crotalus durissus terrificus venom. Although the mechanism is unclear, theaflavins is suspected to be significantly involved. (11)
• Thea sinensis Melanin: Melanin extracted from Thea sinensis is a high molecular part of tea polyphenols with physiochemical characteristics similar to typical melanin. TSM has exhibited a wide range of biochemical and pharmacological activities - antioxidant, free radical scavenging, immunomodulatory, as well as protective activity against toxic substances - snake venoms, benzidine, among others.
• Nephroprotective / Cisplatin-Induced Nephrotoxicity: Thea sinensis melanin pre-administration can prevent the renal toxic effects of cisplatin as evidenced by inhibition of BUN elevation, prevention of oxidative stress, complete blockade of cisplatin-induced elevation of S creatinine.(13)
• Hepatoprotective Against Acetaminophen-Induced Hepatic Injury: Study showed melanin derived from Thea sinensis leaves has protective effects against hepatic injury induced by NAPAP (N-acetyl-p-aminophenol). (14)
• Antioxidant / Radioprotector: Study evaluated the effect of black tea extract against consequences of radiation exposure. The BTE scavenged free radicals and dose-dependently inhibited Fenton reaction-mediated 2-deoxyribose degradation and lipid peroxidation. Extract also exhibited maximum protection against radiation-induced damage in V79 cells. It is possible the key player in radioprotection is elimination of ROS. (16)
• Neurochemical and Behavioral Effects: Study was designed to monitor the effects of green tea extracts in male albino rats for neurochemical and behavioral effects. Results showed decreased in food intake, increase in locomotive activities, anxiolytic effects, and increase in dopamine and serotonin turnover. (17)
• Genoprotective: Study evaluated the genoprotective effects of two types of green tea in an in-vitro and human supplementation trial. In-vitro testing of tea-treated cells showed increased resistance of lymphocytic DNA to H2O2-induced challenge. In the supplementation trial, a significant increase in resistance was also observed. Results showed significant genoprotective effects and evidence for green tea as a "functional food." (18)
• Antioxidant / α-Glucosidase and α-Amylase Inhibitory Activities: Study of tea fruit peel extracts showed antioxidant activities on DPPH, ABTS, and reducing activity. Various extracts also exhibited excellent inhibitory activity against α-glucosidase and mild inhibition of α--amylase activity. (19)
• Antioxidant / Tea Flowers: Study of tea flower extract and fractions exhibited inhibitory effects on hydroxyl radicals and DPPH radicals. Flavones, polyphenols, and catechin contents were highest in the EE and EEA fractions. (20)
• Modulation of Telomerase in Collagen-Induced Arthritis: Study evaluated the therapeutic potency of Camellia sinensis stew in an experimental model of rheumatoid arthritis in Leis rats. Evidence suggests telomerase is involved in the pathogenesis of rheumatoid arthritis. The CSS significantly reduce paw edema. Histopath findings showed reduced inflammatory responses and bone erosion in joints of the treated rats. There was also significant reduction of telomerase activity. (25)
• Review / Anticancer: Study reports on a total of 27 systematic reviews and/or meta-analyses that investigated the association between green tea consumption and cancer risk. In general, there was an inverse association for green tea consumption and risk of gastrointestinal, esophageal (women), lung (non-smoking women), ovarian, prostate, and breast cancer. Evidence for a protective role of tea consumption on development of cancers of the liver, colorectum, pancreas, urinary tract, prostate, glioma, lymphoma, and leukemia was insufficient. (26)
• Interactions: Green tea can act as an antioxidant and induced superoxide dismutase enzyme which can scavenge free oxygen radicals generated by radiotherapy. In a pharmacokinetic study in rats and in vitro, green tea consumption has been reported to increase the plasma concentration of 5-FU. (26)
• Wound Healing Potential: Study evaluated the effects of topical application of C. sinensis extract on the rate of wound closure and histology of wound area. Wounds treated with extract and Intrasite gel healed significantly earlier. Histological exam showed the wounds had less scar, with less inflammatory cells and more collagen and angiogenesis. (27)
• Comparison of Antioxidative Effects of Green and Black Tea: Study evaluated the comparative effects of black and green tea extracts in rats challenged with sodium oxalate to induce lipid peroxidation. Results showed the tea extracts have antioxidant properties and that the green tea extract is more potent. (28) Green tea, the unoxidized leaf of C. sinensis, contains nearly 4000 bioactive compounds. Its health benefits is largely attributed to catechins (flavanols), together with flavonols (kaempferol, quercetin, and myricetin), which together make up 30 to 40% of fresh green tea leaves d/w. Green tea contains higher polyphenol and lower caffeine content than black tea. In contrast, black tea is fully oxidized, with higher caffeine content that makes up about 2-5% of dried leaf weight. (30)
• Antifungal / Anti-Dandruff: Study evaluated the in vitro antifungal activity of various extracts of Camellia sinensis and Acacia sinuate against dandruff causing Pityrosporum ovale. At concentrations of 10, 5, and 2.5 mg/ml, extracts of C. sinensis exhibited greater inhibitory effect on Pityrosporum ovale compared to A. sinuate. (see constituents above) (32)
• Toxicity Studies / Leaves: (1) Study of Camellia sinensis leaf extract (2 g/kg; 1.94 mL/kg) administered orally in Sprague-Dawley rats showed a minimum lethal dose >2 g/kg. Results showed no mortality. (2) The oral LD50 for rats was >2 g/kg for C. sinensis leaf extract (both green and black tea). (3) Dermal LD50 was >1860 mg/kg rats. There was slight to moderate erythema reported. (4) Camellia sinensis caused no adverse effects administered orally to pregnant rats up to 1336 mg/mL in drinking water. (5) FDA considered C. sinensis as GRAS for use as food additive. (34)
Extracts, capsules, ointments, tea seed oil in the cybermarket.