Figure 4.

In vitro anti-tyrosinase activity of Plectranthus spp. (A) Organic extracts at 50 g/mL. (B) Aqueous extracts at 50 g/mL. (C) Isolated compounds at 50 g/mL. The results are presented as means percentage values, considering the absorbance of kojic acid as the positive control. Data are expressed as the mean ± SD (n = 3) *p < 0.05 **p < 0.005 ***p < 0.0001 vs negative control (DMSO 0.5% (v/v) in PBS buffer). DMSO: dimethyl sulfoxide; ns: not significant; PBS: phosphate-buffered saline; SD: Standard Deviation. Values were determined by one-way ANOVA followed by Tukey HSD comparison test.