Extracts from white tea may be able to protect the skin from cancer, report researchers in the US.
Scientists at University Hospitals of Cleveland and Case Western Reserve University have proven that ingredients in the tea can boost the immune function of skin cells and protect them against the damaging effects of the sun. The discovery could be important in the fight against skin cancers, concluded the researchers.
Dr Elma Baron, director of the Skin Study Center at UHC and CWRU, said: "We found the application of white tea extract protects critical elements of the skin's immune system. Similar to the way oxidation causes a car to rust, oxidative stress of the skin causes a breakdown in cellular strength and function. The white tea extract protects against this stress."
"This study further demonstrates the importance of researching how plant products can actually protect the skin," she added.
As part of the study, scientists applied a white tea extract cream to one patch of skin on the subject's buttock (skin that is not ordinarily exposed to much sunlight), while another area was left unprotected. Both areas were then exposed to artificial sunlight. Researchers then reapplied the white tea extract to the area previously coated. Three days later the scientists compared the patches of skin on a cellular level.
They found that the white tea extract protected against obliteration of the Langerhans cells, which were damaged in the sun-exposed skin not treated with the extract. In the immune system, the Langerhans cells in the outer layer of the skin (epidermis) are the outermost reach of the immune system, and are the first to come into contact with foreign agents. They are thought of as 'watchdog cells', essential in detecting germs and mutated proteins produced by cancerous cells, but because of their location, the Langerhans cells are very sensitive to damage by sunlight.
The investigators then tested whether the preserved immune system cells in the white tea extract-protected skin would still function properly after exposure to sunlight; they discovered the immune function was indeed restored by the extract. They also found that the DNA damage that can occur in cells after exposure to sunlight was limited in the skin cells protected by the white tea extract.
Researchers believe the antioxidant properties of the white tea extract are the effective agent; if so, this suggests that the agent may provide anti-ageing benefits. The same process of oxidative stress in skin cells that leads to immune system damage can also promote skin cancer and photo damage, such as wrinkling or mottled pigmentation.
Dr Kevin Cooper, chairman of the department of dermatology at UHC and CWRU, said: "We know that younger skin tends to be able to resist the oxidative stress associated with exposure to the destructive rays of sunlight. The white tea extract also appears to build the skin's resistance against stresses that cause the skin to age."
Researchers at the Skin Study Center at UHC and CWRU have also found that ingredients in green tea decreased the direct effects of sunburn. White and green teas contain the highest amounts of antioxidants of all tea varieties, but white tea is the least processed form of tea and is rarely used in consumer products.
The study was funded by Origins Natural Resources, a division of The Estee Lauder Companies (ELC).