title: (-)-Epicatechin-3-gallate, a green tea polyphenol is a potent agent against UVB-induced damage in HaCaT keratinocytes.
abstract: (-)-Epicatechin-3-gallate (ECG) is a polyphenolic compound similar to (-)-epigallocatechin-3-gallate (EGCG) which is abundant in green tea. Numerous workers have proposed that EGCG protects epidermal cells against UVB-induced damage. However, little has been known about whether ECG protects keratinocytes against UVB-induced damage. We decided to investigate the protective effects and underlying mechanisms of ECG on UVB-induced damage. Cell viability was determined by the MTT assay. Activation of ERK1/2, p38 and JNK was analyzed by Western blotting. Intracellular H2O2 production and DNA content was analyzed by flow cytometry. Lipid peroxidation was assayed by colorimetry. In our study, we found that ECG dose-dependently attenuated UVB-induced keratinocyte death. Moreover, ECG markedly inhibited UVB-induced cell membrane lipid peroxidation and H2O2 generation in keratinocytes, suggesting that ECG can act as a free radical scavenger when keratinocytes were photodamaged. In parallel, H2O2-induced the activation of ERK1/2, p38 and JNK in keratinocytes could be inhibited by ECG. UVB-induced pre-G1 arrest leading to apoptotic changes of keratinocytes were blocked by ECG. Taken together, we provide here evidence that ECG protects keratinocytes from UVB-induced photodamage and H2O2-induced oxidative stress, possibly through inhibition of the activation of ERK1/2, p38 and JNK and/or scavenging of free radicals.
authors.affiliation: School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan.
authors.forename: Chieh-Chen
authors.initials: CC
authors.lastname: Huang
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Wu
authors.forename: Jia-You
authors.initials: JY
authors.lastname: Fang
authors.forename: Han-Sun
authors.initials: HS
authors.lastname: Chiang
authors.forename: Shao-Kuan
authors.initials: SK
authors.lastname: Chen
authors.forename: Bing-Huei
authors.initials: BH
authors.lastname: Chen
authors.forename: Ying-Ting
authors.initials: YT
authors.lastname: Chen
authors.forename: Chi-Feng
authors.initials: CF
authors.lastname: Hung
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology*; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D002460:Cell Line; D004247:DNA / Q000032:analysis / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D015227:Lipid Peroxidation / Q000187:drug effects; D010636:Phenols / Q000302:isolation & purification / Q000494:pharmacology; D059808:Polyphenols; D013473:Sunscreening Agents / Q000302:isolation & purification / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D013473:Sunscreening Agents; D002392:Catechin; D004247:DNA; C062669:epicatechin gallate; D006861:Hydrogen Peroxide; D048049:Extracellular Signal-Regulated MAP Kinases