Compounds in green tea may one day be able to treat common skin diseases and wounds, reports a researcher in the US.
A team at the Medical College of Georgia's department of Oral Biology studied the effects of the most abundant green tea polyphenol, EGCG, on human skin cells and found that EGCG reactivated dying skin cells.
"Cells that migrate toward the surface of the skin normally live about 28 days, and by day 20 they basically sit on the upper layer of the skin getting ready to die. But EGCG reactivates them. I was so surprised," said Dr Stephen Hsu, study leader.
Dr Hsu was previously involved in work that found green tea polyphenols can help eliminate free radicals, which can cause cancer by altering DNA. He also found that polyphenols safeguard healthy cells while prompting cancer cells to die.
The researcher reports that green tea polyphenols are not absorbed beyond the epidermis (the outer layer), so any benefits are limited to that outer layer of skin. This is important because skin cells are in a constant state of renewal, rapidly dividing until they reach the epidermis, where they begin differentiating. But once they reach the surface of the skin, their metabolic activity slows dramatically and they prepare to die. EGCG seems to rejuvenate these skin cells however.
"When exposed to EGCG, the old cells found in the upper layers of the epidermis appear to start dividing again," Dr Hsu said. "They make DNA and produce more energy. They are reactivated."
While further research is needed, he suggests that if dying skin cells can be energised, skin condition could be improved. This could benefit skin conditions including psoriasis, rosascea, wrinkles and wounds.
"If skin cells surrounding wounds or infections don't heal in time, fibroblasts in the connective tissue may rush in to fill the void and cause scar tissue formation. If we can spur the skin cells to differentiate and proliferate, we can potentially accelerate the wound-healing process and prevent scarring," said Dr Hsu.
This could have significant outcome for conditions such as diabetes, which stubbornly inhibits the wound-healing process, he added.
The research is published in the online version of the Journal of Pharmacology and Experimental Therapeutics.