title: Molecular mechanisms of green tea polyphenols with protective effects against skin photoaging.
abstract: Whereas green tea has historically been consumed in high quantities in Northeast Asia, its popularity is also increasing in many Western countries. Green tea is an abundant source of plant polyphenols exhibiting numerous effects that are potentially beneficial for human health. Accumulating evidence suggests that green tea polyphenols confer protective effects on the skin against ultraviolet (UV) irradiation-induced acceleration of skin aging, involving antimelanogenic, antiwrinkle, antioxidant, and anti-inflammatory effects as well as prevention of immunosuppression. Melanin pigmentation in the skin is a major defense mechanism against UV irradiation, but pigmentation abnormalities such as melasma, freckles, senile lentigines, and other forms of melanin hyperpigmentation can also cause serious health and aesthetic issues. Furthermore, UV irradiation initiates the degradation of fibrillar collagen and elastic fibers, promoting the process of skin aging through deep wrinkle formation and loss of tissue elasticity. UV irradiation-induced formation of free radicals also contributes to accelerated photoaging. Additionally, immunosuppression caused by UV irradiation plays an important role in photoaging and skin carcinogenesis. In this review, we summarize the current literature regarding the antimelanogenic, antiwrinkle, antioxidant, and immunosuppression preventive mechanisms of green tea polyphenols that have been demonstrated to protect against UV irradiation-stimulated skin photoaging, and gauge the quality of evidence supporting the need for clinical studies using green tea polyphenols as anti-photoaging agents in novel cosmeceuticals.
authors.affiliation: a The Hormel Institute, University of Minnesota , Austin , Minnesota , USA.
authors.forename: Eunmiri
authors.initials: E
authors.lastname: Roh
authors.affiliation: a The Hormel Institute, University of Minnesota , Austin , Minnesota , USA.|b WCU Biomodulation Major, Department of Agricultural Biotechnology and Center for Food and Bioconvergence , Seoul National University , Seoul , Republic of Korea.|c Advanced Institutes of Convergence Technology, Seoul National University , Suwon , Republic of Korea.
authors.forename: Jong-Eun
authors.initials: JE
authors.lastname: Kim
authors.affiliation: c Advanced Institutes of Convergence Technology, Seoul National University , Suwon , Republic of Korea.
authors.forename: Jung Yeon
authors.initials: JY
authors.lastname: Kwon
authors.affiliation: d Skin Research Institute, Amorepacific Corporation R&D Center , Yongin , Republic of Korea.
authors.forename: Jun Seong
authors.initials: JS
authors.lastname: Park
authors.affiliation: a The Hormel Institute, University of Minnesota , Austin , Minnesota , USA.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Bode
authors.affiliation: a The Hormel Institute, University of Minnesota , Austin , Minnesota , USA.
authors.forename: Zigang
authors.initials: Z
authors.lastname: Dong
authors.affiliation: b WCU Biomodulation Major, Department of Agricultural Biotechnology and Center for Food and Bioconvergence , Seoul National University , Seoul , Republic of Korea.|c Advanced Institutes of Convergence Technology, Seoul National University , Suwon , Republic of Korea.|e Research Institute of Bio Food Industry, Institute of Green Bio Science and Technology, Seoul National University , Pyeongchang , Republic of Korea.
authors.forename: Ki Won
authors.initials: KW
authors.lastname: Lee
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D006801:Humans; D007108:Immune Tolerance; D059808:Polyphenols / Q000494:pharmacology*; D015595:Skin Aging / Q000187:drug effects* / Q000528:radiation effects; D013662:Tea / Q000737:chemistry*; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D000975:Antioxidants; D059808:Polyphenols; D013662:Tea
keywords: Green tea; UV irradiation; photoaging; polyphenols; skin