Camellia sinensis (Tea) in the Prevention of UV-Induced Carcinogenesis: A Mechanistic Overview

Abstract

Ultraviolet radiation (UVR)-induced cancers include melanomas and two types of malignant • keratinocytes, the basal-cell carcinomas (BCC) and squamous-cell carcinomas (SCC). Sun-protection products reduce the risk of erythema and DNA damage but are observed to be not • that effective in preventing UVR-induced ill effects and immune suppression. One approach to protect humans from the deleterious effects of UV irradiation is to use chemopreventive agents. The polyphenols present in tea ( • Camellia sinensis ) have been reported to possess health bene fi ts, including protection from UV carcinogenesis and other ill effects. Tea and its polyphenols (1) act as free radical scavengers and antioxidants, (2) repair, (6) modulate apoptosis, (7) modulate the immune system by inducing immunoregulatory cytokine interleukin IL12, and inhibit UV-induced immunosuppression and stimulate the cytotoxic T cells in a tumor microenvironment, (8) affect fat layers of the skin, and (9) inhibit angiogenesis and metastasis. This review addresses the scienti fi c observations validating the protective effects of tea and its phytochemicals in preventing UV-induced carcinogenesis.