Anti-photoaging activities of Sorbaria kirilowii ethanol extract in UVB-damaged cells.

Sorbaria kirilowii (Regel) Maxim, a plant found in China, Korea, Japan, and east of Europe, is a common herb used for traditional medicinal purposes. However, its ability to prevent photoaging has not been studied. In this study, we investigated the anti-photoaging functions of an ethanol extract (Sk-EE) of S. kirilowii (Regel) Maxim using human keratinocytes exposed to UVB. First, we analyzed the cytotoxicity of Sk-EE. Then, we determine the expression of genes related to inflammation, collagen degradation, and moisture retention. We also explored the anti-photoaging mechanism of Sk-EE by determining correlated signaling pathways and target molecules using reporter gene assays and immunoblotting analyses. Sk-EE treatment of cells increased hyaluronic acid synthase (HAS), filaggrin (FLG), and collagen type I alpha 1 (COL1A1) expression. Sk-EE dose-dependently inhibited the UVB-induced expression of matrix metalloproteinases (MMPs) 1, 2, 9 and cyclooxygenase (COX)-2 by blocking the activator protein (AP)-1 signaling pathway, in particular the phosphorylation of c-Jun N-terminal kinase (JNK), p38, and extracellular response kinase (ERK). In addition, c-Fos and c-Jun were targeted by Sk-EE. Our results indicate that Sk-EE has anti-inflammatory and skin-protective properties, and could be a candidate to treat signs of photoaging.