Description
The phenolic compounds in tea (tea polyphenols) are also known as catechins. In green tea, the four major catechins are (-)-epigallocatechin-3-gallate (EGCG) and its derivatives including (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epicatechin (EC). EGCG takes around 50-80% of the total catechin in green tea and it has been shown to be responsible for much of the health promoting ability of green tea.
Tea polyphenols exhibit anti-carcinogenic, anti-oxidative, anti-allergic, antiviral, anti-hypertensive, anti-atherosclerosis, anti-cardiovascular disease and anti-hypercholesterolemic activities. EGCG has shown to inhibit hepatitis C virus entry and carcinogenesis. Studies suggest that tea polyphenols may help treat health conditions including atherosclerosis, high cholesterol, and cancers including bladder cancer, breast cancer, ovarian cancer, colorectal cancer, esophageal cancer, lung cancer, pancreatic cancer, prostate cancer, skin cancer, and stomach cancer. Tea polyphenols could be helpful in treating inflammatory diseases.
Effects
Green tea extracts contain polyphenolic compounds which act on a number of biochemical pathways,
therefore yielding anti-oxidant, anti-inflammatory, and anti-carcinogenic effects. Epigallocatechin-3-
gallate is the primary active ingredient in the green tea. A study demonstrated that green tea extracts
suppress mushroom tyrosinase, which may be responsible for the skin-lightening effect.Still, more
studies are indicated to substantiate this data.
References
[1] N. Khan, H. Mukhtar (2011) Tea polyphenols for health promotion, Life Sci., 81, 519-533
[2] S. Ciesek, T. von Hahn, CC. Colpitts, LM. Schang, M. Friesland, J. Steinmann, MP. Manns, M. Otto, H. Wedemeyer, P. Meuleman, T. Pietschmann, E. Steinmann (2011) The green tea polyphenol, epigallocatechin-3-gallate, inhibits hepatitis C virus entry, Hepatology, 54, 1947-1955
[3] http://www.umm.edu
Chemical Properties
Green tea extract is prepared from natural dried leaves of the tea plant. Black tea is oxidized green tea. Both have been used for thousands of years in Asia as a beverage and medicine. Green tea extract is a bioflavonoid-rich, potent extract, which is used primarily for quenching free radicals. The absolute is prepared by alcoholic extraction of the concrete, or it is sometimes co-distilled from the concrete. The distilled products are viscous, amber-colored liquids with a rich, delicate, sweet, woody, herbaceous odor. Also see Tea.
Uses
green tea extract (Camellia sinensis L.) is a powerful anti-oxidant because of its catechin content, it is also known to be an antibacterial, anti-inflammatory, and a stimulant. In clinical studies, green tea demonstrates an ability to prevent or at least postpone the onset of such illnesses as cancer and heart disease. This is attributed to the catechin component’s ability to penetrate into a cell, thereby protecting the cell from free radicals and associated damage. Because of its anti-oxidant properties, green tea is usually incorporated into anti-aging formulations. When applied topically, it can also reduce skin swelling. In addition, it can be found in sunscreens, given its ability to extend the product’s SPF. The extract and its associated catechins can be obtained from both the plant and its dried leaves. other constituents of green tea include caffeine and phenolic acids.
Definition
ChEBI: 5,7-Dihydroxy-2-(3,4,5-trihydroxyphenyl)-3,4-dihydro-2H-chromen-3-yl 3,4,5-trihydroxybenzoate is a catechin.
Aroma threshold values
Aroma characteristics in 100% ethanol for black tea distillate light: dry leafy, fresh brewed tea with hints of green, floral and hay. Aroma characteristics in 100% ethanol for black tea distillate brewed: characteristic dry leafy, floral, herbal, green, woody brown notes, slightly clooked fruity nuance
Taste threshold values
Taste characteristics at 0.05%: sweet, refreshing and tea-like with an herbal and hay-like nuance and an astringent tannin afternote. Taste characteristics at 80 to 200 ppm for black tea distillate light: fresh brewed tea, delicate, green leafy, slightly bitter and astringent with a slight floral nuance. Taste characteristics at 100 to 200 ppm for black tea distillate brewed: strong black tea-like with green leafy, floral and fruity nuances. Slightly astringent with a tea aftertaste.
benefits
Tea polyphenol, also called green tea extract, are a mixture of chemical compounds, such as flavanoids and tannins, found naturally in tea. These chemical compounds are believed to be beneficial to human health. Polyphenols are powerful antioxidants, which can reduce the risk of developing coronary artery disease and a number of other health problems.
