Ultraviolet irradiation induces significant changes to skin connective tissues as a result of the degradation of collagen, which is a major structural component of the extracellular matrix. This process may be mediated by matrix metalloproteinases. In this study, we examined the protective effect of a polyphenolic flavone, luteolin, on the expression of two matrix metalloproteinases, MMP1 and MMP9, in UVA and UVB irradiated human dermal fibroblast cells. Luteolin is found in many medicinal plants as well as in a large number of vegetables, fruits and a variety of spices. It has a number of biological activities including anticancer, antioxidant, antiinflammatory, antiallergic and immunomodulatory activities. Human dermal fibroblast cells were treated with luteolin at 1 to 10 uM, then irradiated with UVA. Cells and culture supernatant were harvested 24 h after irradiation.
Our results show that luteolin at 1 to 10 uM dose dependently suppressed the expression of MMP1 and MMP9 genes in UVA and UVB exposed HDF cells, as measured by quantitative real-time reverse transcription polymerase chain reaction. Luteolin was also found to reduce the production of MMP1 protein in UVA and UVB exposed HDF cells detected by enzyme-linked immunosorbent assay in a dose dependent manner. The release of MMP9 was also reduced by luteolin in UVB irradiated HDF cells in a dose-dependent manner. Our results indicate that luteolin can inhibit UV induced MMP1 and MMP9 expression in HDF cells. Therefore, they may be potentially useful in the prevention and treatment of skin photoaging.