New research published in Experimental Dermatology introduces a new plant-derived agent, which protects skin from the harmful effects of ultraviolet (UV) irradiation. "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 defense systems," says Gitta Neufang, a researcher involved in the work from Beiersdorf AG (Hamburg, Germany). "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." 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 pretreated with licochalcone a produced a higher amount of self-protecting, antioxidant molecules. Consequently, significantly fewer 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.
These findings show that the skin's own defense system can be stimulated by the application of licorice extract. In combination with UV-filters this approach therefore might provide superior sun protection by not only offering physical but also biological sun protection. "Even with the best sun-protecting filter system (SPF50+) 2% of UV-rays still reach the skin and cause damage," says Neufang. "We hope that our study helps to improve the effectiveness of sunscreens to protect from the harmful aspects of sun exposure."—Jennifer Nied