Figure 8.

Effects of PH on melanin production and tyrosinase activity in normal human melanocytes. Cells were treated with PH at the indicated concentrations for 72 h. α-MSH (200 nM) and arbutin (100 μM) were used as a negative and positive control, respectively. (a) The melanin content and (b) tyrosinase activity are expressed as percentages relative to untreated cells. All experiments were carried out in triplicate, and the results are expressed as the mean ± SD. ^## p < 0.01, compared with the untreated cell group and * p < 0.05, ** p < 0.01, compared with the α-MSH-treated group.