Protective effect of ferulic acid-hyaluronic acid copolymer against UVB irradiation in a human HaCaT cell line.

Excessive UVB exposure increased the production of reactive oxygen species (ROS), leading to oxidative damage and epidermal inflammation. To enhance UVB protection effect, a strong phenolic antioxidant, ferulic acid (FA) was designed onto HA via a free radical mediated method. Our previous work has confirmed its structural characterization and in vitro antioxidant. The aim of this study was to evaluate its protective effects against UVB-induced damage in human HaCaT cells. We observed a significant reduction in cell viability to 57.43 % following UVB exposure at a dose of 80 mJ/cm. However, pretreatment with FA-HA (250 to 2000 μg·mL) significantly attenuated cytotoxicity in a dose-dependent manner. Furthermore, FA-HA was found to suppress the intracellular generation of ROS and up-regulated the expression of the antioxidant enzyme superoxide dismutase (SOD). The elevated levels of pro-inflammatory cytokines, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α) as well as the mRNA expression of matrix metalloproteinase-1/9 (MMP-1/9) induced by UVB irradiation, were also effectively reduced by FA-HA. Additionally, FA-HA treatment decreases the phosphorylation of mitogen-activated protein kinase (MAPK) and activator protein-1 (AP-1), ultimately preventing apoptosis. These findings suggest that FA-HA is a promising candidate for UVB protection in skincare formulations.