Protective Effect of (-)-Epigallocatechin Gallate against Photo-Damage Induced by Ultraviolet A in Human Skin

Purpose: To investigate the photoprotective effect of (-)-epigallocatechin gallate (EGCG), one of tea catechins, on human skin fibroblast (HSF) irradiated by ultraviolet A. Methods: HSF cells were incubated in serum-free Dulbecco's Modified Eagle's Medium (DMEM) with or without EGCG for 2 h, and then irradiated by UV A. Blank (control) was incubated in DMEM without EGCG and UV A-irradiation. Cell viability was determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method. Protein concentration of the samples was determined using a PA102 Bradford protein assay kit. Malondialdehyde (MDA), glutathione peroxidase (GSH-Px) and superoxide anion radicals were determined using MDA assay kit, GSH-Px assay kit and superoxide anion radical assay kit, respectively. Results: HSF viability decreased with dosage of UV A irradiation with 50 % lethal dose （LD50）of 9 J/cm2. Pre-incubation of HSF in 10 μg/mL EGCG aqueous solution for 2 h before exposure to UV A alleviated the suppressive effect of UV A on HSF. Compared to UVA irradiation alone, HSF viability and GSH-Px activity in the EGCG pretreatment increased by 18.3 and 103.4 %, accompanying decrease in level of superoxide anion radicals and MDA by 44.6 and 16.6 %, respectively