Figure 1: MTT-based cytotoxicity assay. Human skin fibroblast (TIG-199) cells were treated with different concentration of HE (0, 0.1, 0.25, 0.5, 0.75, 1.0, 2.0, and 5.0 mg/mL), and total viable cells were count-based on MTT assay. Each value is the mean ± SD of three independent experiments. Asterisks indicate values which are significantly different from control.