Sulforaphane inhibits cancer growth by stimulating our own detoxifying enzymes and it also (according to at least one study) prevents sun damage. Researchers at the Johns Hopkins University School of Medicine in Baltimore first identified sulforaphane in broccoli sprouts which, of all the cruciferous vegetables, have the highest concentration of sulforaphane. Sprouts have a 50 times higher concentration of sulforaphane than mature broccoli.
The John Hopkins researchers found that sulforaphane can help treat sun damage after the fact. "We weren't looking for a sunscreen effect. 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 if it can help repair damage already done to sun-exposed skin, it could be an important ingredient for after sun treatments.
SulforaWhite, made by a Swiss company called Mibelle, is an ingredient formulated to target age spots. It is made from watercress sprouts (lepidium sativum sprout extract) glycerin, lecithin, phenoxyethanol and water. At concentrations of 2-5% it is supposed to be good at treating existing age spots and also, by inhibiting melanin production, preventing future damage. The former it does by deactivating reactive oxidants in keratinocytes by stimulating the body's cellular defense system. Then it inhibits α-MSH, a natural hormone which induces skin pigmentation, from binding on melanocytes.