Green tea prevents non-melanoma skin cancer by enhancing DNA repair

Excessive exposure of the skin to solar ultraviolet (UV) radiation is one of the major factors for the development of skin cancers, including non-melanoma. For the last several centuries the consumption of dietary phytochemicals has been linked to numerous health benefits including the photoprotection of the skin. Green tea has been consumed as a popular beverage world-wide and skin photoprotection by green tea polyphenols (GTPs) has been widely investigated. In this article, we have discussed the recent investigations and mechanistic studies which define the potential efficacy of GTPs on the prevention of non-melanoma skin cancer. UV-induced DNA damage, particularly the formation of cyclobutane pyrimidine dimers, has been implicated in immunosuppression and initiation of skin cancer. Topical application or oral administration of green tea through drinking water of mice prevents UVB-induced skin tumor development, and this prevention is mediated, at least in part, through rapid repair of DNA. The DNA repair by GTPs is mediated through the induction of interleukin (IL)-12 which has been shown to have DNA repair ability. The new mechanistic investigations support and explain the anti-photocarcinogenic activity, in particular anti-non-melanoma skin cancer, of green tea and explain the benefits of green tea for human health.

Research highlights
► Excessive exposure of the skin to solar ultraviolet (UV) radiation leads to the development of melanoma and non-melanoma skin cancers.
► UV-induced DNA damage has been implicated in immunosuppression and initiation of UV-carcinogenesis.
► Topical application or oral administration of green tea polyphenols (GTPs) in drinking water prevents UV-induced non-melanoma skin cancer risk in mice.
► GTPs inhibit non-melanoma skin cancer risk through the enhancement of DNA repair.