Cytotoxicity and Photoprotection of (-)-Loliode

HDF cells (ATCC^®PCS201012™, Manassas, VA, USA) were cultured in the medium mixed with F-12 and DMEM (1:3) supplemented with 10% FBS and 1% P/S. HDF cells were seeded at a concentration of 5.0 × 10⁴ cells/mL for experiments. To analyze the cytotoxicity of (-)-loliode on HDF cells, HDF cells were seeded and incubated with (-)-loliode (6.25, 12.5, 25, 50, and 100 μg/mL). After 24 h, the cell viabilities of (-)-loliode-treated HDF cells were measured by the MTT assay according to the method described by Wang et al. [23 (link)]. To evaluate the photoprotective effect of (-)-loliode in HDF cells, HDF cells were seeded and treated with (-)-loliode (6.25, 12.5, and 25 μg/mL). (-)-Loliode-treated cells were exposed to UVB (50 mJ/cm²) and the intracellular ROS level and the viability of UVB-irradiated HDF cells were determined with the DCF-DA assay and the MTT assay, respectively [11 (link)]. In addition, the collagen synthesis level and the expression of MMPs were assessed with ELISA kits (Sigma, St. Louis, MO, USA) using the cell culture medium [1 (link),11 (link)].