Myricetin is a widely distributed flavonol that is found in many plants, including tea, berries, fruits, vegetables, and medicinal herbs. Abundant sources provide interesting insights into the multiple mechanisms by which myricetin mediates chemopreventive effects on skin cancer. Myricetin strongly inhibited tumor promoter-induced neoplastic cell transformation by inhibiting MEK, JAK1, Akt, and MKK4 kinase activity directly. In a mouse skin model, myricetin attenuated the ultraviolet B (UVB)-induced COX-2 expression and skin tumor formation by regulating Fyn. Myricetin-mediated inactivation of Akt in the UVB response plays a role in regulating UVB-induced carcinogenesis. Recently, myricetin was found to inhibit UVB-induced angiogenesis by targeting PI3-K in an SKH-1 hairless mouse skin tumorigenesis model. Raf kinase is a critical target for myricetin in inhibiting the UVB-induced formation of wrinkles and suppression of type I procollagen and collagen levels in mouse skin. Accumulated data suggest that myricetin acts as a promising agent for the chemoprevention of skin cancer.
© 2011 New York Academy of Sciences.