A team of scientists led by Albena Dinkova-Kostova at the Johns Hopknis University in Baltimore, US, say that further to sulforaphanes known indirect antioxidant properties, the compound has now been proven to counteract the carcinogenic response to ultraviolet light when applied topically to hairless mice.
The scientists exposed the mice to a dose of UV light comparable to a person sunbathing by the sea on a clear summer's day, twice a week for 20 weeks. Following the exposure the broccoli sprout extract was applied to the backs of the mice, in varying doeses, for five days a week over an 11 week period.
Although a host of vegetables, including broccoli, contain sulforaphane, broccoli sprouts have been proven to have by far the highest concentration of the compound.
Acetone, which is a basic ingredient in nail varnish, was used as the delivery vehicle for the sulforaphane, and was applied on its own to the control group of mice. At the end of the study all of the control group of mice had developed signs of cancer.
However, the results showed that in the group of mice treated with sulforaphane extract, the incidence of tumors was reduced by half in those mice receiving the highest doses. Likewise the rate of tumor was higher in mice with lower does, but the team equally reported that growth was reduced.
"We weren't looking for a sunscreen effect," Dinkova-Kostova said. "The sulforaphane-containing extract was applied after the period of regular exposure to ultra-violet light. That's more relevant, since most people receive some sun damage to their skin in childhood, particularly adults who grew up before effective sunscreen lotions were developed."
It was already known that sulforaphane boosts protective and detoxifying reactions in skin cells, but now, added to that, is the fact that it can help repair damage already done to sun-exposed skin, making it a particularly important ingredient for after sun treatments.
"Our findings suggest a promising strategy for skin cancer prevention after exposure to UV light," Dinkova-Kostova said.
The teams findings could pave the way for one of the first after-sun treatments that is proven to help reverse sun damage from. With rates of skin cancer rising each year due to the depletion of the ozone layer and increasing exposure to the sun, such a product could literally prove to be a life saver to many individuals.
Broccoli oil extract has been manufactured as an ingredient for cosmetic applications for some years now. Currently Natural Plant Products, a US company based in Oregon, is a major supplier of the oil, which is used in a variety of hair care applications.