Anti-Skin Aging Effect of Syriacusins from Hibiscus Syriacus on Ultraviolet-Irradiated Human Dermal Fibroblast Cells

Photosensitized peroxidation of membrane lipids has been implicated in skin pathologies such as phototoxicity and premature aging. We have previously reported that syriacusin compounds isolated from Hibiscus Syriacus inhibited lipid peroxidation. Here, we investigated whether syriacusins could be effective inhibitor to skin aging using ultraviolet-irradiated human dermal fibroblast cells (HDFCs). Syriacusins A, B, and C inhibit the activity of human neutrophil elastase (HNE), a serine protease to degrade extracellular matrix (ECM) proteins including elastin, with IC50s of 8.0, 5.2, and 6.1 μM, respectively. No changes in cell viability were detected by syriacusins A and B in UV-B (10 mJ/cm) irradiated HDFCs. Matrix metalloproteinase (MMP)-1 expression in HDFCs was increased by UV-B irradiation. MMP-1 expression in UV-B irradiated HDFCs was decreased by 10 μM and 20 μM syriacusin A to 50% and 20% of untreated control, respectively. Syriacusin B treated with 20 μM reduced MMP-1 expression in UV-B irradiated HDFCs to 60% of untreated control. Syriacusin A also inhibited MMP-2 expression accompanying the increase of type-I pro-collagen in UV-B irradiated HDFCs. These results demonstrate that syriacusin A could be a more effective compound to inhibit skin aging caused by UV irradiation. It suggests that syriacusins A and B might be developed as possible agents to treat or prevent skin aging.