Protective Effects of Lindera coreana on UVB-induced Oxidative Stress in Human HaCaT Keratinocytes

The present study was designed to investigate the protective effect of ethanol extracts from Lindera coreana leaves (LCE) on UVB-induced oxidative stress in HaCaT keratinocytes. The HaCaT cells were pretreated with LCE for 24 h and then exposed to UVB (20 mJ/cm(2)) for 2 h. UVB significantly decreased the cell viability (p<0.05). LCE did not exhibit significantly cytotoxic effects and increased the viability of the HaCaT cells in a concentration-dependent manner. To further investigate the protective effects of LCE on UVB-induced oxidative stress in HaCaT cells, the cellular levels of reactive oxygen species (ROS), lipid peroxidation and endogenous antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-px), were analyzed. LCE decreased the intracellular levels of ROS and lipid peroxidation and increased the activity of antioxidant enzymes. These results suggest that LCE exerted cytoprotective activity against UVB-induced oxidative stress in HaCaT cells through the inhibition of lipid peroxidation, reduction of ROS levels and stimulation of antioxidant enzymes activities. In addition, LCE also decreased the TNF-α, IL-1β and IL-6 levels in UVB-irradiated HaCaT cells.