Photo-protective effect of americanin B against ultraviolet B-induced damage in cultured human keratinocytes.

Jian Zheng, Mei Jing Piao, Ki Cheon Kim, Cheng Wen Yao, Ji Won Cha, Jennifer H Shin, Suk Jae Yoo, Jin Won Hyun

Index: Environ. Toxicol. Pharmacol. 38(3) , 891-900, (2014)

Full Text: HTML

Abstract

Excessive ultraviolet (UV) radiation, a constituent of sunlight, can induce multiple types of skin damage. We recently demonstrated that americanin B, a lignin compound, protected cells against hydrogen peroxide (H2O2)-induced damage by exerting antioxidant effects and inhibiting apoptosis. In this study, we investigated the ability of americanin B to protect against cell injury induced by UVB (280-320nm), the most harmful UV wavelengths, in human HaCaT keratinocytes. Americanin B absorbed UVB, eliminated UVB-induced intracellular reactive oxygen species (ROS), and decreased the extent of UVB-induced oxidative modification of lipids, proteins, and DNA. In addition, americanin B inhibited UVB-induced apoptosis, as indicated by reductions in apoptotic body formation and DNA fragmentation. Furthermore, americanin B reversed the depolarization of the mitochondrial membrane induced by UVB exposure. These protective activities were associated with down-regulation of apoptosis-promoting proteins, Bax, caspase-9, and caspase-3 and up-regulation of an apoptosis inhibitor, Bcl-2. These results suggest that americanin B can protect human keratinocytes against UVB-induced cell damage. Copyright © 2014 Elsevier B.V. All rights reserved.