The damaging effects of UV (ultraviolet) radiation can be appreciably reduced with the topical application of a broccoli extract, according to an article in Proceedings of the National Academy of Sciences. UV radiation is a common cause of cancer for humans.
The scientists from Johns Hopkins explain that their findings, which involved animal studies as well as human studies, reveal that the level of erythema (skin reddening) caused by UV rays is substantially reduced when this extract is applied to the skin.
Paul Talalay, M.D., professor of pharmacology, explains that this broccoli extract is not a sunscreen; it does not absorb the UV light and stop it from entering the skin, as sunscreens do. It gets into the cells and causes an increase in the production of several enzymes that shield cells from UV damage. The advantage of this is that it is much longer-lasting than any sunscreen – several days, in fact. The scientists said the protection is still there when no extract is present on/in the skin.
“Treatment with this broccoli sprout extract might be another protective measure that alleviates the skin damage caused by UV radiation and thereby decreases our long-term risk of developing cancer,” Talalay said.
The extract is called sulforaphane and comes from broccoli sprouts. Talalay first identified it with his team over 15 years ago. It was then shown to play a role in preventing the development of tumors in several animals that had been given cancer-causing chemicals.
The current team first tested on mouse models with skin cancer, and then on six healthy human volunteers. Each volunteer had small patches, less than one inch in diameter, of his/her skin exposed to a pulse of UV radiation. Some of the patches were treated with the broccoli extract while others were not.
UV-induced redness and inflammation was 37% lower (average) at the highest UV radiation doses when the extract had been applied. They found the protection was still there three days later. The researchers also found that protection varied greatly depending on the person – protection ranged from 8% to 78%. Talalay believes this variation may be due to the volunteers’ different skin types, dietary habits and genetic differences.
The scientists said that conventional sunscreens were basically useless in these trials.
“Sulforaphane mobilizes cellular defenses that protect skin against damage by UV radiation”
Paul Talalay, Jed W. Fahey, Zachary R. Healy, Scott L. Wehage, Andrea L. Benedict, Christine Min, and Albena T. Dinkova-Kostova
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0708710104
Click here to view abstract online
Written by: Christian Nordqvist