Green tea could hold promise as a new treatment for skin disorders such as psoriasis and dandruff, Medical College of Georgia researchers say.
Researchers studied an animal model for inflammatory skin diseases, which are often characterized by patches of dry, red, flaky skin caused by the inflammation and overproduction of skin cells. Those treated with green tea showed slower growth of skin cells and the presence of a gene that regulates the cells life cycles.
Psoriasis, an autoimmune disease, causes the skin to become thicker because the growth of skin cells is out of control, says Dr. Stephen Hsu, an oral biologist in the MCG School of Dentistry and lead investigator on the study published in the Aug. 18 edition of Experimental Dermatology.In psoriasis, immune cells, which usually protect against infection, instead trigger the release of cytokines, which causes inflammation and the overproduction of skin cells.
Other autoimmune diseases with similar side effects include lupus, which can lead to skin lesions, and dandruff.
Green tea, already shown to suppress inflammation, helps by regulating the expression of Caspase-14, a protein in genes that regulates the life cycle of a skin cell.
That marker guides cells by telling them when to differentiate, die off and form a skin barrier, Dr. Hsu says.In people with psoriasis, that process is interrupted and the skin cells dont die before more are created and the resulting lesions form.
Animal models treated with green tea also showed reduced levels of proliferating cell nuclear antigen, a gene expressed when skin cells multiply. In psoriasis, the gene is over-expressed and speeds production of skin cells.
Before treatment, the antigen, PCNA, was present in all layers of the skin, Dr. Hsu says.Typically, PCNA is only found in the basal layer, the innermost layer where skin cells continually divide and new cells push the older ones to the skin surface, where they eventually slough off. After being treated with green tea, the animal models showed near-normal levels of PCNA in only the basal layers.
This research is important because some treatments for psoriasis and dandruff can have dangerous side effects, he says.