Ultraviolet A radiation of the skin tissue causes production of reactive oxygen species, resulting in oxidative stress, cell damage and eventual cell death or skin cancer. Epidemiological studies suggest that consumption of fruits and vegetables, which are rich in anthocyanins, has been associated with a lower incidence of cancer. Cyanidin is found in red colored fruits such as blackberry and bilberry. Ding et al showed that cyanidin 3-glucoside possess chemopreventive and chemotherapeutic activities, and could be used for skin protection. They found that cyanidin scavenged free radicals induced by ultraviolet B radiation. Their in-vivo test with rats also demonstrated the chemoprotective action of skin of rats. Treatment of the rats with cyanidin decreased the number of tumors which were induced with carcinogens. Cyanidin acts by reducing the transactivation of NF-kappaB and activator protein-1, by reducing the expression of cyclooxygenase-2 and tumor necrosis factor-alpha, and by inhibiting of MAPK activity. Furthermore, they found that cyanidin inhibited the proliferation of cultured lung carcinoma cells and migration and invasion epithelial carcinoma cells in nude mice . Cimino et al. also tested the protective effect of cyanidin on skin cells exposed to UVB radiation. They found that the treatment of the skin cells with cyanidin attenuated biological changes caused by the radiation (increased translocation of transcription factors, overexpression of the proinflammatory cytokines, cleavage of procaspase-3 and DNA fragmentation) .
Tarozzi et al. reported that cyanidin 3-O-beta-glucopyranoside reduced free radical formation in cultured skin cells exposed to ultraviolet A radiation and that the phytochemical could be used as a novel agent for skin protection. When the skin cells were treated with the cyanidin glycoside the cell apoptosis was reduced by 61%. Cyanidin 3-O-beta-glucopyranoside also reduced DNA fragmentation and inhibited free radical formation. The antioxidant activity was more concentrated in the cell membrane than in the citosol, indicating that cyanidin-3-O-beta-glucopyranoside is concentrated in the cell membrane . All these studies suggest that cyanidin might successfully be employed for skin protection as a photoprotective agent.
 Cyanidin 3-glucoside, a natural product derived from blackberry, exhibits chemopreventive and chemotherapeutic activity. J Biol Chem. 2006 Jun 23;281(25):17359-68.
 Protective effects of cyanidin 3-O-beta-glucopyranoside against UVA-induced oxidative stress in human keratinocytes." Photochem Photobiol. 2005 May-Jun;81(3):623-9.
 Effect of cyanidin 3-O-glucoside on UVB-induced response in human keratinocytes. J Agric Food Chem. 2006 May 31;54(11):4041-7.