The Protective Effect of Adenocaulon himalaicum Edgew. and Its Bioactive Compound Neochlorogenic Acid against UVB-Induced Skin Damage in Human Dermal Fibroblasts and Epidermal Keratinocytes

Skin aging induced by ultraviolet (UV) irradiation increases expression of matrix metalloproteinase-1 (MMP-1) and destroys collagen fibers, as a result accelerating wrinkle formation. Natural products have been received scientific attention as utilized agents against photoaging. The aim of this study was to investigate the protective effect of Adenocaulon himalaicum Edgew. extract (AHE) against ultraviolet B (UVB)-induced skin damage, and to explain the underlying mechanisms in human dermal fibroblasts and epidermal keratinocytes. AHE effectively protects skin photoaging by preventing collagen degradation through MMP-1 inhibition via the MAPK/AP-1 signaling pathway. AHE significantly increased the expression of skin hydration factors, such as filaggrin, involucrin, loricrin, and caspase-14. To find how AHE possesses a direct impact on cellular activities, we identified neochlorogenic acid as a bioactive component of AHE for the first time. Neochlorogenic acid showed the anti-photoaging effect through ameliorating UVB-induced collagen degradation, reinforcing the skin barrier. Like the AHE-regulating mechanism, neochlorogenic acid modulates the MAPK/AP-1 signaling pathway and skin hydration factors. Taken together, these results suggest that AHE and neochlorogenic acid are well-qualified candidate for enhancing the conditions of photoaged skin.