Percent viable mammalian cells (measured as average absorbance ratio (test agent relative to DMSO)) for cytotoxicity analysis of compounds 7, 18, and 19 (tested in triplicate) at 64 and 128 µM against HaCaT cells over a 24 hour period using the MTS 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Dimethyl sulfoxide (DMSO) was used as a negative control to determine a baseline measurement for the cytotoxic impact of each compound. The absorbance values represent an average of a minimum of three samples analyzed for each compound. Error bars represent standard deviation values. A one-way ANOVA, with post hoc Dunnet’s multiple comparisons test, determined statistical difference between the values obtained for each compound and DMSO (P < 0.05).