ABSTRACT
BACKGROUND: Tea polyphenols have been found to exert beneficial effects on the skin via their antioxidant properties. AIMS: We sought to determine whether topical application of green tea or white tea extracts would prevent simulated solar radiation-induced oxidative damages to DNA and Langerhans cells that may lead to immune suppression and carcinogenesis. METHODS: Skin samples were analysed from volunteers or skin explants treated with white tea or green tea after UV irradiation. In another group of patients, the in vivo immune protective effects of green and white tea were evaluated using contact hypersensitivity to dinitrochlorobenzene. RESULTS: Topical application of green and white tea offered protection against detrimental effects of UV on cutaneous immunity. Such protection is not because of direct UV absorption or sunscreen effects as both products showed a sun protection factor of 1. There was no significant difference in the levels of protection afforded by the two agents. Hence, both green tea and white tea are potential photoprotective agents that may be used in conjunction with established methods of sun protection.
Subject(s)
Plant Extracts/pharmacology , Skin/drug effects , Sunscreening Agents/pharmacology , Tea/chemistry , Ultraviolet Rays/adverse effects , 8-Hydroxy-2'-Deoxyguanosine , Administration, Cutaneous , Adolescent , Adult , Antigens, CD1/analysis , DNA Adducts/analysis , DNA Damage/drug effects , Deoxyguanosine/analogs & derivatives , Deoxyguanosine/analysis , Dermatitis, Contact/etiology , Dinitrochlorobenzene , Drug Evaluation, Preclinical , Flavonoids/pharmacology , Humans , Langerhans Cells/drug effects , Middle Aged , Phenols/pharmacology , Polyphenols , Skin/chemistry , Skin/radiation effects , Tea/classification , Young AdultABSTRACT
Compounds derived from botanical sources, such as polyphenols from tea, have been of interest as possible therapeutic agents. Their benefits in terms of cancer chemoprevention have also been investigated primarily through in vitro and animal in vivo studies. Ultraviolet light from solar radiation has been proven to initiate and promote skin cancer, which is the most common malignancy in light-skinned populations. This review discusses the effects of tea polyphenols in preventing cutaneous carcinogenesis. Although many of the mechanisms and pathways discussed may be applicable to other carcinogens, this review focuses mainly on those related to ultraviolet light-induced processes and potential action sites for tea polyphenols. Since caffeine is a component of tea, and has also been suggested as a possible chemoprotective agent, it is included in this review. Based on data from numerous studies published in the scientific literature, tea polyphenols are promising chemopreventive agents against ultraviolet-induced skin cancers. Their antioxidant properties, inhibitory effects on signal transduction pathways, cell proliferation, angiogenesis and capacity for apoptosis induction, as well as possible immune protective effects, are among the mechanisms that contribute to skin cancer prevention.
