London, Feb 19 (IANS): Scientists have discovered a new plant-derived agent that protects the skin from the harmful effects of ultra-violet (UV) irradiation.

The skin is constantly challenged by environmental stressors such as UV radiation and chemicals. To cope with UV radiation, various skin cells have evolved a complex protective antioxidant defence system.

"We found out that the antioxidant active Licochalcone A, which is the main component of the root extract of the plant Glycyrrhiza inflata (Chinese Licorice), is able to protect the skin from subsequent UV irradiation damage from within by strengthening the skin's own defence systems.

"Thus plant extracts with the described profile are able to provide a protective shield from sun exposure supporting and going beyond the action of sunscreens regarding sun protection", said Gitta Neufang, a researcher involved in the work from Beiersdorf AG, Hamburg, Germany.

In order to test the effects of the plant-derived active Licochalcone A in cell culture, Neufang and colleagues isolated human skin cells and irradiated them with solar simulated light mimicking sun exposure.

They were able to show that skin cells pre-treated with Licochalcone A produced a higher amount of 'self-protecting', antioxidant molecules.

Consequently, significantly less harmful radicals were detected in Licochalone A treated human skin cells.

In addition, they also conducted a study with healthy volunteers demonstrating that the application of a lotion containing Licochalcone A-rich root extract on the inner forearms for two weeks protected the skin from damage after UV irradiation.

"Even with the best sun-protecting filter system (SPF50 ) 2 percent of UV-rays still reach the skin and cause damage."We hope that our study helps to improve the effectiveness of sunscreens to protect from the harmful aspects of sun exposure," Neufang said.

The findings were published in Experimental Dermatology.