US researchers reported Tuesday that the properties of green tea might offer a new treatment for skin disorders such as psoriasis and dandruff.

In skin diseases like psoriasis, skin cells multiply out of control, causing the skin to be thicker and to flake off. Immune cells in the body are also activated, causing inflammation to set in.

In a study published on the latest issue of Experimental Dermatology, researchers from Medical College of Georgia studied an animal model for inflammatory skin diseases, and those treated with green tea showed slower growth of skin cells and the presence of a gene that regulates the cells' life cycles.

Animal models treated with green tea also showed reduced levels of proliferating cell nuclear antigen (PCNA), a gene expressed when skin cells multiply. In psoriasis, the gene is over-expressed and speeds production of skin cells.

Dr. Stephen Hsu, lead investigator on the study, said that the traditional treatment of ultraviolet light and medication can control the lesions of the skin, but may cause squamous cell carcinoma -- the second most common form of skin cancer, after long-term use.

Green tea, which is plant-derived, may be an alternative, he says. But researchers must work to overcome some barriers with the treatment and further study is needed to determine the full effects.

The chemicals in green tea are so active that they are oxidized too quickly when mixed with other ingredients. They also dissolve in water, which cannot penetrate the skin's barrier.

Researchers are looking for a balanced formula that can dissolve in fats, which can permeate the skin, Dr. Hsu said.

(Xinhua News Agency August 8, 2007)