B16 cells were treated with 50 mM CNN and isotonic samples of mannose (50 mM), isomaltose (50 mM), NaCl (25 mM), and glycine (50 mM) for 4 days. Levels of melanin and total protein were determined, as shown in A and B, respectively. **, p<0.01; statistically significant differences were analyzed by one-way ANOVA and Dunnett’s post hoc testing. Data are representative results of at least two independent experiments.