Anti-melanogenic Activity of Extracts from Carex pumila Thunb. Inhabiting Along the Nakdong River (Republic of Korea)

Carex pumila Thunb. is a plant native to East Asia, Australia, and New Zealand. However, its effect on skin melanogenesis has not been investigated. In the present study, we evaluated its anti-melanogenic properties using B16F10 melanoma cells and zebrafish larvae in the presence or absence of α-melanocyte stimulating hormone (α-MSH). In this study we revealed that concentrations below 50 µg/mL did not induce any cytotoxicity in B16F10 melanoma cells and cardiotoxicity in zebrafish larvae. However, 50 µg/mL treatment significantly inhibited α-MSH-induced extracellular (from 181.24% α 0.62% to 105.15% α 0.31%) and intracellular melanin contents (from 119.8% α 1.2% to 53.4% α 1.7%) as well as intracellular tyrosinase activity (from 143.9% α 4.2% to 103.7% α 1.4%) in B16F10 melanoma cells. At 25 µg/mL and 50 µg/mL concentrations, it could significantly inhibit α-MSH induced hyperpigmentation in zebrafish larvae (from 100% α 2.3% to 60.7% α 1.3% and 47.5% α 1.9% respectively). Additionally, the extract suppressed α-MSH-induced cAMP-CREB-MITF signaling pathway and consequently inhibited tyrosinase expression in B16F10 melanoma cells. In conclusion, our results indicate that this plant extract could suppress the cAMP-CREB-MITF axis which consequently inhibits tyrosinase mediated melanogenesis.