Ultraviolet radiation is a major environmental harmful factor on human skin. In this paper, we investigate the potential mechanism of Houttuynia cordata extract on UVB-induced HaCaT keratinocyte cell death and inflammation. We found that Houttuynia cordata ethyl acetate extract fraction (HC-EA) protected against UVB-induced cell damage. The HPLC results indicate that quercitrin and hyperoside are the major polyphenolics in HC-EA and are responsible for providing protection against UVB-induced cell death. These responses were associated with the regulation of caspase-9 and caspase-3 activation, which rescued HaCaT cells from UVB-induced apoptosis. In addition, HC-EA, quercitrin, and hyperoside attenuated UVB-induced inflammatory mediators, including IL-6, IL-8, COX-2, and iNOS. Furthermore, the treatment of cells with HC-EA and its active compounds abolished intracellular ROS and increased levels of heme oxygenase-1 and superoxide dismutase. UVB-induced ROS production mediated Akt and mitogen activated protein kinases (MAPKs) pathways, including p38, ERK, and JNK. Our results show HC-EA, quercitrin, and hyperoside decreased UVB-induced p38 and JNK phosphorylation, while increasing ERK and Akt phosphorylation. MAPKs and Akt mediated cell survival and death were confirmed by specific inhibitors to Akt and MAPKs. Thus, HC-EA, which contains quercitrin and hyperoside, protected keratinocyte from UVB-induced oxidative damage and inflammation through the modulation of MAPKs and Akt signaling.
About Me
MSc student in Department of Biochemistry, Faculty of Medicine, CMU, Thailand.
MSc student in Department of Biochemistry, Faculty of Medicine, CMU, Thailand.