The effect of xanthorrhizol on the expression of matrix metalloproteinase-1 and type-I procollagen in ultraviolet-irradiated human skin fibroblasts

Matrix metalloproteinases (MMPs) are key regulators of the skin photoaging process that is set in motion by exposure to ultraviolet (UV) irradiation. This skin damage results from UV-induced generation of reactive oxygen species, which are associated with upregulation of MMPs and decreased collagen synthesis. We investigated the effects of xanthorrhizol, isolated from Curcuma xanthorrhiza, on the expression of MMP-1 and type-I procollagen in UV-irradiated human skin fibroblasts. Fibroblasts cultured in the presence or absence of purified xanthorrhizol or C. xanthorrhiza extract were irradiated with UV (20 mJ/cm ²), and MMP-1 and type-I procollagen levels were measured using Western blot analysis. Xanthorrhizol (0.001-0.1 μM) and C. xanthorrhiza extract (0.01-0.5 μg/mL) induced a significant, dose-dependent decrease in the expression of MMP-1 protein, and increased the expression of type-1 procollagen. At a concentration of 0.1 μM, xanthorrhizol nearly completely abrogated MMP-1 expression. The MMP-1-suppressing and type-1 procollagen-inducing effects of xanthorrhizol treatment were greater than those of epigallocatechin 3-O-gallate (EGCG), which is known to be a natural anti-aging agent. These results suggest that xanthorrhizol is a potential candidate for the prevention and treatment of skin aging.