2.5. Cell Viability Assay

The cytotoxicity of the samples was evaluated using the MTT assay. B16-F10 melanoma cells (1 × 10⁴ cells/well) were cultured in a 96-well plate and incubated with various concentrations of extract and fractions (12.5, 25, 50, and 100 μg/mL) or arbutin (100 μg/mL) for 24 h at 37 °C. After incubation, 500 μg/mL MTT solution was added to the wells, and the plate was further incubated for 4 h at 37 °C. Then, the media of each well was removed, and 200 μL dimethyl sulfoxide (DMSO) was added to solubilize the formazan crystals. The absorbance of the plate was detected at 570 nm on a microplate reader (Synergy HTX Multi-Mode Reader, BioTek, Winooski, VT, USA).