Suppression of Ultraviolet B‐mediated Matrix Metalloproteinase Generation by Sorbus commixta Twig Extract in Human Dermal Fibroblasts

Sorbus commixta is a traditional oriental medicinal plant that grows in East Asian countries such as Korea, Japan and China. The twig of S. commixta has been considered valuable for centuries to treat diseases including asthma, cough and other bronchial disorders. However, the effect of S. commixta twig extract on human skin has not been investigated well. The present study aimed at assessing the antiphotoaging effect of S. commixta twig ethanol extract (STE) on ultraviolet B (UVB)‐induced matrix metalloproteinase (MMP) levels and its underlying mechanism in human dermal fibroblasts. In this study, we found that STE (12.5–50 μg mL−1) treatment significantly inhibited UVB‐induced MMP‐1, MMP‐2 and MMP‐3 expression, concomitant with a downregulation of intracellular ROS generation. These effects might be associated with a STE‐induced inhibition of the mitogen‐activated protein kinase (MAPK) pathway. Furthermore, STE also downregulated UVB‐induced c‐Fos expression in a concentration‐dependent manner, but had no inhibitory effect on c‐Jun phosphorylation. Taken together, these results indicate that STE may be an antiphotoaging agent and that its effect may occur via its inhibition of MMPs expression and MAPK pathway activation. It has been demonstrated that UVB generates a significant amount of matrix metalloproteinases (MMPs) via an increase in intracellular ROS, which may be responsible for the degradation of ECM components such as collagen, elastin, proteoglycans, and fibronectin. In the present study, we have proven that Sorbus commixta twig ethanol extract (STE) suppresses UVB‐induced MMP production by inhibiting c‐Fos expression, which could be linked to a MAPK‐dependent mechanism in human dermal fibroblasts.