Antioxidants in Tea
Antioxidants are chemicals that naturally help fight the harmful oxidation effects of unstable molecules in your body called free radicals that occurs naturally in the body when you are exposed to harmful environmental factors. Free radicals have extra electrons around them that bombard the molecules of cell membranes which leads to cell damage. Antioxidants take up these extra electrons so that your cells don’t have to. Free radicals may come from environmental contaminants such as radiation, pollution and exposure to toxins; but they also form as a result of normal bodily processes such as breathing oxygen.
There are three primary types of antioxidants found in nature. These include phytochemicals, vitamins, and enzymes. Although black tea has high levels of some essential antioxidant enzymes and vitamins such as Magnesium and Folate is it the Phytochemicals in tea that make them so powerful.
Phytochemicals are the antioxidants that are naturally used by plants to protect themselves against free radicals . Studies show that humans who eat sources of phytochemicals also benefit from the antioxidant properties of the plant. Phytochemicals are broken down into the following categories:
• Allyl sulfides
Main flavonoids of a living tea leaf
Flavonoids are secondary metabolites (a group of naturally occurring biochemicals) that help a plant to grow strong and attain its various biological characters, such as its smell, colour or self-defense. The amount and varieties differ in different plants and in different parts and growing stages of a plant. The most predominant flavonoids in a growing young tea leaf are:
Catechins in tea
• Catechin, Epigallocatechin (EGC)
• Epigallocatechin 3-gallate (EGCG)
• Epicatechin (EC)
• Epicatechin 3-gallate (ECg, or ECG, or EC3G)
Catechins protect cell DNA. They are anti-mutagenic, anti-inflammatory and anti-pathogenic all delivered in a cup of tea.
Of all the catechins, EGCG, is a unique catechin in tea, has repeatedly demonstrated itself as the most potent health contributive factor in tea. It accounts for 50~75% of the catechins in green teas.
Once a tea leaf is plucked, its flavonoids very slowly undergo a process of enzyme triggered oxidation that cause them, in particular the catechins, to transform into various substances, some are other forms of flavonoids, some yet other substances that may influence the taste and aroma of the final product. The production of various categories of tea is largely based on the control of this oxidation phenomenon. This oxidation of catechins is called “fermentation” in the tea production process.
Flavonols in tea
Acts as an antioxidant by reducing oxidative stress. Anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic, antiosteoporotic, estrogenic/antiestrogenic, anxiolytic, analgesic, and antiallergic activities. It has been linked with many sucessful anti-cancer treatments and and it is currently under consideration as a possible cancer treatment.
Myricetin works by disrupting cellular pathways. It interacts with enzymes and suppresses their activities (enzyme inhibition). Myricetin, is an anti-inflammatory, prevents blood clots, has many anti-cancer properties, increases glucose uptake thus helping manage diabetes, slows the progression of Alzheimers disease, protects the heart, controls fat deposition and helps prevent weight gain, anti-microbial, helps protect the skin against UV radiation and prevents skin wrinkles, protects eyesight and increases bone mass, Myricetin also increases iodine uptake as well as iodine retention by thyroid cells.
Inflammation is the root of most diseases, and Quercetin effectively fights anti-inflammatory related diseases such as: Atherosclerosis, circulation, high cholesterol, insulin resistance and diabetes, heart disease, eye-related disorders including cataracts, allergies, asthma and hayfever, stomach ulcers, cognitive impairment, gout, viral infections, inflammation of the prostrate, bladder and ovaries, chronic fatigue syndrome, cancer, chronic infections of the prostrate and skin disorders
Flavones in tea
Anti-inflammatory, antidepressant-like effects, anti-cancer properties, protects the heart, prevents bone loss, stimulates brain cell generation.
Luteolin interferes with nearly all types of cancer cells.
It inhibits the growth of new blood vessels in tumors, the metabolism of carcinogens, as well as stopping the progression of the cell cycle in cancer cells. Luteolin also induces cell death in cancer cells. Luteolin is also an anti-inflammatory, antioxidant, prevents UVB-induced skin aging, luteolin can be used in the prevention and treatment of cardiovascular diseases, protects the brain from neurological impairments, anti-viral properties, helps prevent cataracts, Luteolin has anti-oxidant and anti-inflammatory effects which can reduce the effects of multiple sclerosis, Luteolin has anti-oxidant and anti-inflammatory effects which can reduce the effects of multiple sclerosis
Flavonoids in green tea
In the case of a fine green tea, the plucked leaf is withered very briefly for slight dehydration and then put through heat to halt the enzyme-triggered oxidation. The most original and quantity of flavonoids are thus kept. They can take up an average of 30% of the dry weight of the tea, dependent on the tea variety, pluck quality and harvest season. That means you have on average 300 mg of catechins and other flavonoids in each gram of tea leaves.
Flavonoids in black tea
When the fresh leaves are taken to produce black tea, a large proportion of these flavonoids and catechins is oxidized to become other substances, mostly flavonoids of larger molecular structures, such as:
• Theaflavins (TF)
• Thearubigins (TR)
• Theabrownins (TB)
While most of medical researches on tea’s health potential focus around green tea catechins, in particular EGCG, there are a number done on theaflavins, finding that they may also be contributive to reduction of cardiovascular diseases and prevention of diabetes. Theaflavins contribute to the yellowish orange colour of the black tea infusion. They make up on average 6% of the black tea flavonoids.
Much fewer studies have been done on theabrownins, which are a lot more abundant in post-fermented teas, but with promising results on cholesterol control resulting in a reduced risk for heart disease. The antioxidants in green, black, and oolong teas can help block the oxidation of LDL (bad) cholesterol, increase HDL (good) cholesterol and improve artery function.
Drinking a cup of tea a few times a day helps to absorb antioxidants and other nutritional plant compounds. In green-tea drinking cultures, the usual amount is three cups per day. Allow tea to steep for three to five minutes to bring out its catechins. The best way to get the catechins and other flavonoids in tea is to drink it freshly picked and freshly brewed. Decaffeinated, bottled ready-to-drink tea (bag) preparations, and instant teas have less of these compounds.
Note that tea can impede the absorption of iron from fruits and vegetables. Adding lemon or milk or drinking tea between meals will counteract this problem.