Ginsenosides Rb1 and Rg1 Stimulate Melanogenesis in Human Epidermal Melanocytes via PKA/CREB/MITF Signaling

Figure 4

The effect of the PKA inhibitor on Rb1- and Rg1-induced MITF expression and melanin content in melanocytes. Melanocytes were exposed to ginsenoside Rb1 (100 μM) or ginsenoside Rg1 (300 μM) with or without pretreatment with the PKA inhibitor H-89 (10 μM) for 1 hr. After a further 24 hrs of culture, the levels of p-CREB, MITF, and tyrosinase were quantified and normalized to the levels of β-actin by western blotting analysis ((a), (b)). After 72 hrs of exposure to Rb1 and Rg1, cellular melanin content (c) was determined. ^∗∗𝑃<0.01, as compared with control; ^#𝑃<0.05, as compared with cells treated with ginsenoside Rg1 alone; ^∗𝑃<0.05, as compared with cells treated with ginsenoside Rb1 alone (as determined by one-way ANOVA).

(a)

(b)

(c)