Chloroquine decrease melanin accumulation of African-American human skin equivalent (MEL-B). MEL-B were treated with 0.5 mM chloroquine, 4.0 mM quinine salicylate, 3 mg/ml arbutin, or controls (either water or 30:70 water/PEG) for 10 or 13 days. Representative data from multiple experiments are presented. A, changes in melanin content of MEL-B. Data are presented as the percentage of control, and each column represents the mean ± S.D. of multiple experiments. B, phase-contrast microscopic images of MEL-B. C, immunohistochemical appearances of MEL-B after Fontana-Masson staining to emphasize melanin content.