Effects of ginseng saponins isolated from red ginseng on ultraviolet B-induced skin aging in hairless mice

Abstract

It is well-known that chronic ultraviolet B (UVB) exposure at low-dose causes skin photoaging including increases in skin thickness and wrinkle formation and reduction in skin elasticity. This study examined the effects of total saponins and ginsenoside Rb 1 isolated from Red Ginseng roots on skin thickness, elasticity, and wrinkle formation caused by long-term, low-dose UVB irradiation in hairless mice. The topical application of total ginseng saponins (10 pg or 100 ng/mouse) and ginsenoside Rb 1 (100 fg, 10 pg, or 1 ng/mouse) significantly inhibited increases in skin thickness and wrinkle formation and the reduction in skin elasticity induced by long-term UVB irradiation. Furthermore, we examined the histological effects of total saponins and ginsenoside Rb 1 in the skin of UVB-irradiated hairless mice. The increases in apoptotic, Ki-67-, and 8-hydroxy-2′-deoxyguanosine-positive cells induced by UVB exposure were prevented by the topical application of total saponins and ginsenoside Rb 1. Furthermore, total saponins and ginsenoside Rb 1 prevented the disruption of collagen fibers induced by the long-term UVB irradiation. Ginsenoside Rb 1 (100 fg, 10 pg, and 1 ng/ml) increased the Bcl-2 expression level in UVB-treated human keratinocytes. The protective effect of ginsenoside Rb 1 on UVB-mediated apoptosis may be due to the up-regulation of Bcl-2 expression. These results suggest that the protective effect of ginsenoside Rb 1 on skin photoaging induced by chronic UVB exposure may be due to the increase in collagen synthesis and/or the inhibition of matrix metalloproteinase expression in dermal fibroblasts.