Figure 10.

Effect of HRW and EO extracts from E. globulus leaves on the melanin production (A) and tyrosinase activity (B) in 3-isobutyl-1-methylxanthine (IBMX)-stimulated B-16V melanocytes. The cells were treated, in the absence or presence of 0.16 mg/mL EO, 0.8 μg/mL HRW or 40 µM kojic acid (KA) (positive control) for 72 h, with 200 µM IBMX, a melanogenesis inducer. Cells treated with the medium alone were used as the CTRL. The tyrosinase activity and melanin content were determined by a spectrophotometric method. The results were expressed as a percentage (%) of the CTRL, and represent the mean ± SEM of at least three independent experiments. The statistical analysis was performed by one-way ANOVA followed by Dunnett’s and Sidak’s multiple comparison tests. ** p < 0.01 and **** p < 0.0001: significantly different compared to the CTRL. # p < 0.05, ## p < 0.01, and ### p < 0.001: significantly different compared to the IBMX.