Daily Science Journal (Jan. 16, 2008) — Green tea may help protect against autoimmune disease, Medical College of Georgia researchers say.
Dr Stephen Hsu and colleagues found that green tea may help protect against autoimmune disease. (Credit: Image courtesy of Medical College of Georgia)Researchers studied an animal model for type I diabetes and primary Sjogren’s Syndrome, which damages the glands that produce tears and saliva.
They found significantly less salivary gland damage in a group treated with green tea extract, suggesting a reduction of the Sjogren’s symptom commonly referred to as dry mouth. Dry mouth can also be caused by certain drugs, radiation and other diseases.
Approximately 30 percent of elderly Americans suffer from degrees of dry mouth, says Dr. Stephen Hsu, a researcher in the MCG School of Dentistry and lead investigator on the study. Only 5 percent of the elderly in China, where green tea is widely consumed, suffer from the problem.
They found significantly less salivary gland damage in a group treated with green tea extract, suggesting a reduction of the Sjogren’s symptom commonly referred to as dry mouth. Dry mouth can also be caused by certain drugs, radiation and other diseases.
Approximately 30 percent of elderly Americans suffer from degrees of dry mouth, says Dr. Stephen Hsu, a researcher in the MCG School of Dentistry and lead investigator on the study. Only 5 percent of the elderly in China, where green tea is widely consumed, suffer from the problem.
“Since it is an autoimmune disease, Sjogren’s Syndrome causes the body to attack itself and produce extra antibodies that mistakenly target the salivary and lacrimal glands,” he says. There is no cure or prevention for Sjogren’s Syndrome.
Researchers studied the salivary glands of the water-consuming group and a green tea extract-consuming group to look for inflammation and the number of lymphocytes, a type of white blood cells that gather at sites of inflammation to fend off foreign cells.
The group treated with green tea had significantly fewer lymphocytes, Dr. Hsu says. Their blood also showed lower levels of autoantibodies, protein weapons produced when the immune system attacks itself, he says.
Researchers already know that one component of green tea – EGCG – helps suppress inflammation, according to Dr. Hsu. "So, we suspected that green tea would suppress the inflammatory response of this disease. Those treated with the green tea extract beginning at three weeks, showed significantly less damage to those glands over time.”
Researchers also suspect that the EGCG in green tea can turn on the body’s defense system against TNF-alpha – a group of proteins and molecules involved in systemic inflammation. TNF-alpha, which is produced by white blood cells, can reach out to target and kill cells.
“The salivary gland cells treated with EGCG had much fewer signs of cell death caused by TNF-alpha,” Dr. Hsu says. “We don’t yet know exactly how EGCG makes that happen. That will require further study. In some ways, this study gives us more questions than answers.”
These results, published in a recent issue of Autoimmunity, reinforced findings of a 2005 study showing a similar phenomenon in a Petrie dish, Dr. Hsu says. Further study could help determine green tea’s protective role in other autoimmune diseases, including lupus, psoriasis, scleroderma and rheumatoid arthritis, he says.
Adapted from materials provided by Medical College of Georgia.
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Add On Article :
Cup Of Green Tea To Keep The Bacteria Away
Beneficial effects of green tea have been known for millenia, particularly in Asian cultures. An ancient Chinese proverb says: "Better to be deprived of food for three days, than tea for one". A cup of green tea contains up to 200 mg of catechins, whose biological activity has been mainly attributed to its antioxidant activity. Efficiency of green tea extract in oral hygiene has been known for centuries and this gave researchers a clue that antibacterial activity might be involved.
Now researchers from the National institute of Chemistry in Ljubljana, Slovenia discovered that the main ingredients of green tea are able to perform other tricks. They found out that green tea catechins inhibit essential bacterial enzyme DNA gyrase, which is the target of several existing clinically used drugs. By the use of NMR spectroscopy, researchers from Slovenia have now pinpointed the ATP-binding site of DNA gyrase as target of EGCG, the most abundant catechin from the green tea extract. Up to now several compounds targeted against the ATP-binding site of bacteria gyrase have been known but couldn't be used as drugs due to their side effects on mammalian cells.
Lead researcher Roman Jerala, the head of the Laboratory of Biotechnology at NIC explains: "We can anticipate to avoid the problem of toxicity using the compounds based on the green tea catechins, which have centuries of established safety record in the human diet."
This finding may be used to develop even more potent antibacterial compounds. Results were recently published in the Journal of Medicinal Chemistry.
Adapted from materials provided by National Institute Of Chemistry, Slovenia.
Researchers studied the salivary glands of the water-consuming group and a green tea extract-consuming group to look for inflammation and the number of lymphocytes, a type of white blood cells that gather at sites of inflammation to fend off foreign cells.
The group treated with green tea had significantly fewer lymphocytes, Dr. Hsu says. Their blood also showed lower levels of autoantibodies, protein weapons produced when the immune system attacks itself, he says.
Researchers already know that one component of green tea – EGCG – helps suppress inflammation, according to Dr. Hsu. "So, we suspected that green tea would suppress the inflammatory response of this disease. Those treated with the green tea extract beginning at three weeks, showed significantly less damage to those glands over time.”
Researchers also suspect that the EGCG in green tea can turn on the body’s defense system against TNF-alpha – a group of proteins and molecules involved in systemic inflammation. TNF-alpha, which is produced by white blood cells, can reach out to target and kill cells.
“The salivary gland cells treated with EGCG had much fewer signs of cell death caused by TNF-alpha,” Dr. Hsu says. “We don’t yet know exactly how EGCG makes that happen. That will require further study. In some ways, this study gives us more questions than answers.”
These results, published in a recent issue of Autoimmunity, reinforced findings of a 2005 study showing a similar phenomenon in a Petrie dish, Dr. Hsu says. Further study could help determine green tea’s protective role in other autoimmune diseases, including lupus, psoriasis, scleroderma and rheumatoid arthritis, he says.
Adapted from materials provided by Medical College of Georgia.
--------------------------------------------------------------------------------
Add On Article :
Cup Of Green Tea To Keep The Bacteria Away
Beneficial effects of green tea have been known for millenia, particularly in Asian cultures. An ancient Chinese proverb says: "Better to be deprived of food for three days, than tea for one". A cup of green tea contains up to 200 mg of catechins, whose biological activity has been mainly attributed to its antioxidant activity. Efficiency of green tea extract in oral hygiene has been known for centuries and this gave researchers a clue that antibacterial activity might be involved.
Now researchers from the National institute of Chemistry in Ljubljana, Slovenia discovered that the main ingredients of green tea are able to perform other tricks. They found out that green tea catechins inhibit essential bacterial enzyme DNA gyrase, which is the target of several existing clinically used drugs. By the use of NMR spectroscopy, researchers from Slovenia have now pinpointed the ATP-binding site of DNA gyrase as target of EGCG, the most abundant catechin from the green tea extract. Up to now several compounds targeted against the ATP-binding site of bacteria gyrase have been known but couldn't be used as drugs due to their side effects on mammalian cells.
Lead researcher Roman Jerala, the head of the Laboratory of Biotechnology at NIC explains: "We can anticipate to avoid the problem of toxicity using the compounds based on the green tea catechins, which have centuries of established safety record in the human diet."
This finding may be used to develop even more potent antibacterial compounds. Results were recently published in the Journal of Medicinal Chemistry.
Adapted from materials provided by National Institute Of Chemistry, Slovenia.
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