Katiyar S K, Bergamo B M, Vyalil P K, Elmets C A
Department of Dermatology, School of Medicine, University of Alabama at Birmingham, 1670 University Blvd., VH501, Box 202, Birmingham, AL 35294, USA.
J Photochem Photobiol B. 2001 Dec 31;65(2-3):109-14. doi: 10.1016/s1011-1344(01)00248-2.
Green tea is a popular beverage consumed worldwide. The epicatechin derivatives, which are commonly called 'polyphenols', are the active ingredients in green tea and possess antioxidant, anti-inflammatory and anti-carcinogenic properties. Studies conducted by our group on human skin have demonstrated that green tea polyphenols (GTP) prevent ultraviolet (UV)-B-induced cyclobutane pyrimidine dimers (CPD), which are considered to be mediators of UVB-induced immune suppression and skin cancer induction. GTP treated human skin prevented penetration of UV radiation, which was demonstrated by the absence of immunostaining for CPD in the reticular dermis. The topical application of GTP or its most potent chemopreventive constituent (-)-epigallocatechin-3-gallate (EGCG) prior to exposure to UVB protects against UVB-induced local as well as systemic immune suppression in laboratory animals. Additionally, studies have shown that EGCG treatment of mouse skin inhibits UVB-induced infiltration of CD11b+ cells. CD11b is a cell surface marker for activated macrophages and neutrophils, which are associated with induction of UVB-induced suppression of contact hypersensitivity responses. EGCG treatment also results in reduction of the UVB-induced immunoregulatory cytokine interleukin (IL)-10 in skin as well as in draining lymph nodes, and an elevated amount of IL-12 in draining lymph nodes. These in vivo observations suggest that GTPs are photoprotective, and can be used as pharmacological agents for the prevention of solar UVB light-induced skin disorders associated with immune suppression and DNA damage.
绿茶是一种在全球广受欢迎的饮品。表儿茶素衍生物，通常被称为“多酚”，是绿茶中的活性成分，具有抗氧化、抗炎和抗癌特性。我们团队对人体皮肤进行的研究表明，绿茶多酚（GTP）可预防紫外线（UV）-B诱导的环丁烷嘧啶二聚体（CPD），而CPD被认为是UVB诱导的免疫抑制和皮肤癌发生的介质。经GTP处理的人体皮肤可防止紫外线辐射穿透，这通过网状真皮中CPD免疫染色阴性得以证明。在暴露于UVB之前局部应用GTP或其最有效的化学预防成分（-）-表没食子儿茶素-3-没食子酸酯（EGCG）可保护实验动物免受UVB诱导的局部和全身免疫抑制。此外，研究表明，用EGCG处理小鼠皮肤可抑制UVB诱导的CD11b +细胞浸润。CD11b是活化巨噬细胞和中性粒细胞的细胞表面标志物，与UVB诱导的接触性超敏反应抑制的诱导有关。EGCG处理还可导致皮肤以及引流淋巴结中UVB诱导的免疫调节细胞因子白细胞介素（IL）-10减少，引流淋巴结中IL-12含量升高。这些体内观察结果表明，GTP具有光保护作用，可作为预防与免疫抑制和DNA损伤相关的太阳UVB光诱导皮肤疾病的药物。
