Skin cancer is one of the most commonly diagnosed
cancers in the United States. Exposure to ultraviolet-B (UVB) radiation induces
inflammation and photocarcinogenesis in mammalian skin.
Cyanidin-3-glucoside (C3G), a member of the
anthocyanin family, is present in various vegetables and fruits especially in edible berries, and displays potent
antioxidant and anticarcinogenic properties. In this study, we have assessed the in vivo effects of C3G on UVB irradiation induced chronic inflammatory responses in SKH-1 hairless mice, a well-established model for UVB-induced skin
carcinogenesis. Here, we show that C3G inhibited UVB-induced skin damage and
inflammation in SKH-1 hairless mice. Our results indicate that C3G inhibited
glutathione depletion, lipid peroxidation and myeloperoxidation in mouse skin by chronic UVB exposure. C3G significantly decreased the production of UVB-induced pro-inflammatory
cytokines, such as
IL-6 and TNF-α, associated with cutaneous
inflammation. Likewise, UVB-induced inflammatory responses were diminished by C3G as observed by a remarkable reduction in the levels of phosphorylated MAP
kinases, Erk1/2, p38, JNK1/2 and MKK4. Furthermore, C3G also decreased UVB-induced
cyclooxygenase-2 (COX-2),
PGE2 and iNOS levels, which are well-known key
mediators of inflammation and
cancer. Treatment with C3G inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in mice skin. Immunofluorescence assay revealed that topical application of C3G inhibited the expression of
8-hydroxy-2'-deoxyguanosine,
proliferating cell nuclear antigen, and
cyclin D1 in chronic UVB exposed mouse skin. Collectively, these data indicates that C3G can provide substantial protection against the adverse effects of UVB radiation by modulating UVB-induced MAP
kinase and NF-κB signaling pathways.