Nomenclature of Tea
By the time the nomenclaturist Linnaeus published his Species Plantarum (1753), tea had already grown and consumed for centuries and he was aware of the availability of green and black teas.
Accordingly, he identifies two separate species of plants that yield tea: Thea virids (green) and Thea bohen (black).
Those inaccurate classification held until the early 19th century, when it was determined that these two plants were, in fact, one and the same.
The species of the tea plant is Camellia sinensis.
It is in the the family Theaceae of order Theales.
Interestingly enough, over 2000 varieties of tea are derived from this one plant species.
The differences are one function of the way o which the tea leaves are processed.
Sunday, November 08, 2009
Sunday, October 18, 2009
Study of relationship between green tea and cancer
Study of relationship between green tea and cancer
Studies conducted in China revealed that green tea users had an approximate 50% reduction in risk for both esophageal cancer and stomach cancer.
Inhabitants of tea producing districts in Japan have a lower mortality from stomach cancer, possibly the result green tea consumption.
In addition to a regular tea drinking, this population consumes green tea all types of products, including candy, gums, bread, shampoo, lotion, toothpaste, etc.
Contrary to the preceding, however to recent studies found no association between green tea consumption and stomach or colon cancer.
Green tea was linked to a reduced risk of oral cancer in northern Italian and a Chinese population, esophageal cancer in Chinese women, gastric cancer in Swedish adolescents, pancreatic cancer in residents of a retirement community in the United States, and colon cancer in retired male self defense official in Japan.
Cohort studies suggest that there is a protective effect of green tea for colon, urinary bladder, stomach, pancreatic and esophageal cancer.
In Japanese survey, an overall protection by green tea was observed, together with slowdown of the increase of cancer incidence with age. The effects were more pronounced when the tea consumption was more than 10 cups/day.
In another Japanese study, consumption of 7 or more cups per day of green tea significantly decreased the risk of cancer of both the stomach and rectum (by 31% and 54% respectively) compared with non-users.
Regular tea drinkers in China experienced a lower incidence of cancer of the colon, rectum, and pancreas compared with non drinkers of tea.
A case control study from Poland reported a significant reduction in risk of pancreatic cancer with increasing lifetime tea consumption.
Increased green tea consumption was closely associated with decreased axillary lymph node metastases among patients who were premenopausal with stage 1 and 11 breast cancer and overall decreased recurrence of stage 1 and 11 breast cancer.
Study of relationship between green tea and cancer
Studies conducted in China revealed that green tea users had an approximate 50% reduction in risk for both esophageal cancer and stomach cancer.
Inhabitants of tea producing districts in Japan have a lower mortality from stomach cancer, possibly the result green tea consumption.
In addition to a regular tea drinking, this population consumes green tea all types of products, including candy, gums, bread, shampoo, lotion, toothpaste, etc.
Contrary to the preceding, however to recent studies found no association between green tea consumption and stomach or colon cancer.
Green tea was linked to a reduced risk of oral cancer in northern Italian and a Chinese population, esophageal cancer in Chinese women, gastric cancer in Swedish adolescents, pancreatic cancer in residents of a retirement community in the United States, and colon cancer in retired male self defense official in Japan.
Cohort studies suggest that there is a protective effect of green tea for colon, urinary bladder, stomach, pancreatic and esophageal cancer.
In Japanese survey, an overall protection by green tea was observed, together with slowdown of the increase of cancer incidence with age. The effects were more pronounced when the tea consumption was more than 10 cups/day.
In another Japanese study, consumption of 7 or more cups per day of green tea significantly decreased the risk of cancer of both the stomach and rectum (by 31% and 54% respectively) compared with non-users.
Regular tea drinkers in China experienced a lower incidence of cancer of the colon, rectum, and pancreas compared with non drinkers of tea.
A case control study from Poland reported a significant reduction in risk of pancreatic cancer with increasing lifetime tea consumption.
Increased green tea consumption was closely associated with decreased axillary lymph node metastases among patients who were premenopausal with stage 1 and 11 breast cancer and overall decreased recurrence of stage 1 and 11 breast cancer.
Study of relationship between green tea and cancer
Thursday, September 24, 2009
Tea and War
Tea and War
Throughout the nineteenth century tea continued to play a powerful role as an important commodity.
By the end of century tea was an essential part of the daily rations of many armies throughout the world including both British and American.
It was considered necessary, not only because of its soothing effects but perhaps more importantly, because tea necessitated boiling water, thus helping to ward off many of the intestinal diseases that had plagued armies for centuries.
Much has been written about the role tea played during the two world wars, not only as necessary refreshment for the troop but also as an item of trade.
During the first two wars of World War I, from 1914 to 1916, tea as enjoyed by the British as it had been before the war began.
When German submarines began sinking British ships, however supplies became less available and the price of tea rose dramatically.
In response to the scarcity of tea, the government classified it as a luxury and began rationing it to civilians.
The public uproar that resulted soon made it clear that tea would have to be reclassified as a basic necessity, essential for keeping up national morale.
The government then took over all tea imports, fixed process and controlled sales. By 1918, all the tea available in Britain was owned and meted out by the government at the rate of two ounces of tea per week per person.
In 1919, after the war ended, normally auctions resumed and consumption rose to three ounces of tea a head weekly by 1931.
While both wars did have an impact on the world’s consumption of tea, some things never change, and the British continued to import at an astronomic rate.
Primarily through the efforts of the British owned plantations, 470 million pounds of India tea were plucked in 1945, in spite of the turmoil in India during World War II.
This was the largest tea crop ever from India, and British profits in tea increased by 200 percent.
Tea and War
Throughout the nineteenth century tea continued to play a powerful role as an important commodity.
By the end of century tea was an essential part of the daily rations of many armies throughout the world including both British and American.
It was considered necessary, not only because of its soothing effects but perhaps more importantly, because tea necessitated boiling water, thus helping to ward off many of the intestinal diseases that had plagued armies for centuries.
Much has been written about the role tea played during the two world wars, not only as necessary refreshment for the troop but also as an item of trade.
During the first two wars of World War I, from 1914 to 1916, tea as enjoyed by the British as it had been before the war began.
When German submarines began sinking British ships, however supplies became less available and the price of tea rose dramatically.
In response to the scarcity of tea, the government classified it as a luxury and began rationing it to civilians.
The public uproar that resulted soon made it clear that tea would have to be reclassified as a basic necessity, essential for keeping up national morale.
The government then took over all tea imports, fixed process and controlled sales. By 1918, all the tea available in Britain was owned and meted out by the government at the rate of two ounces of tea per week per person.
In 1919, after the war ended, normally auctions resumed and consumption rose to three ounces of tea a head weekly by 1931.
While both wars did have an impact on the world’s consumption of tea, some things never change, and the British continued to import at an astronomic rate.
Primarily through the efforts of the British owned plantations, 470 million pounds of India tea were plucked in 1945, in spite of the turmoil in India during World War II.
This was the largest tea crop ever from India, and British profits in tea increased by 200 percent.
Tea and War
Sunday, September 06, 2009
Antimicrobial Activity of Tea
Antimicrobial Activity of Tea
Medical books written as early as in the Song Dynasty (960 – 1279) in China mention that green tea in combination with ginger can effectively cure dysentery disorders, including those so-called red and white in appearance.
Modern medical research has demonstrated that tea and tea products are active against a wide range of microorganism, implying that tea may be potentially useful for treatment of some infectious illness.
A number of reports indicated that green tea and black tea can inhibit the growth of a wide spectrum of pathogenic bacteria including Staphylococcus aureus, Shigella dysenteriae, Salmonella typhosa, Pseudomonas aeruginosa, Vibrio choilerae, and others.
Both tea powder and tea infusion are active. In a comparison of the activity of green tea and black tea against various bacteria known to cause disease, the Gram-positive bacteria with more sensitive Gram–negative.
In the case of Staphylococcus aureus, black tea showed stringer bactericidal activity than green tea and coffee.
Tea polyphenols are major components responsible for the antibacterial activity of various tea products.
The active tea polyphenols and theaflavins and their minimum inhibition concentration values were estimated in the range of 100-800 ppm.
In addition,, tea aroma compounds such as linalool, geraniol, nerolidol, cis-jasmone and caryophyllene, also display antibacterial activities.
It is of importance that tea can inhibit methicillin resistant Staphylococcus aureus which poses severe problems in clinical chemotherapy.
The anticaries activity of tea has drawn much attention. Tea products have shown inhibitory activity against mutans streptococci and glucosyltransferases.
Mutan streptococci that are known to synthesize glucans have been implicated as primary causative agent of caries.
Two types of glucans, water soluble and water insoluble are synthesized by two different groups of glucosyltransferase in these bacteria.
The water insoluble glucan is highly adhesive to tooth surface resulting in the formation of dental plaque.
The bacteria grow in dental plague, metabolize varies sugars there and produce organic acids, especially lactic acid, which retains in the plaque, eventually to decalcify the tooth enamel and develop dental caries.
An earlier investigation conducted at primary schools over a year has found that the incidence of dental caries among children who took a cup of tea immediately after lunch was found to be significantly lower than that among children who did not.
Various tea extracts have shown bactericidal activity against mutan streptococci. Moreover, several catechins, the components from green tea, are active against cariogenic bacteria.
Antimicrobial Activity of Tea
Medical books written as early as in the Song Dynasty (960 – 1279) in China mention that green tea in combination with ginger can effectively cure dysentery disorders, including those so-called red and white in appearance.
Modern medical research has demonstrated that tea and tea products are active against a wide range of microorganism, implying that tea may be potentially useful for treatment of some infectious illness.
A number of reports indicated that green tea and black tea can inhibit the growth of a wide spectrum of pathogenic bacteria including Staphylococcus aureus, Shigella dysenteriae, Salmonella typhosa, Pseudomonas aeruginosa, Vibrio choilerae, and others.
Both tea powder and tea infusion are active. In a comparison of the activity of green tea and black tea against various bacteria known to cause disease, the Gram-positive bacteria with more sensitive Gram–negative.
In the case of Staphylococcus aureus, black tea showed stringer bactericidal activity than green tea and coffee.
Tea polyphenols are major components responsible for the antibacterial activity of various tea products.
The active tea polyphenols and theaflavins and their minimum inhibition concentration values were estimated in the range of 100-800 ppm.
In addition,, tea aroma compounds such as linalool, geraniol, nerolidol, cis-jasmone and caryophyllene, also display antibacterial activities.
It is of importance that tea can inhibit methicillin resistant Staphylococcus aureus which poses severe problems in clinical chemotherapy.
The anticaries activity of tea has drawn much attention. Tea products have shown inhibitory activity against mutans streptococci and glucosyltransferases.
Mutan streptococci that are known to synthesize glucans have been implicated as primary causative agent of caries.
Two types of glucans, water soluble and water insoluble are synthesized by two different groups of glucosyltransferase in these bacteria.
The water insoluble glucan is highly adhesive to tooth surface resulting in the formation of dental plaque.
The bacteria grow in dental plague, metabolize varies sugars there and produce organic acids, especially lactic acid, which retains in the plaque, eventually to decalcify the tooth enamel and develop dental caries.
An earlier investigation conducted at primary schools over a year has found that the incidence of dental caries among children who took a cup of tea immediately after lunch was found to be significantly lower than that among children who did not.
Various tea extracts have shown bactericidal activity against mutan streptococci. Moreover, several catechins, the components from green tea, are active against cariogenic bacteria.
Antimicrobial Activity of Tea
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