Inhibitory Effects of Ethanol Extracts from Polygoni multiflori radix and Cynanchi wilfordii radix on Melanogenesis in Melanoma Cells

Anti-oxidative activity and tyrosinase inhibitory activity of various ethanol extracts of Polygoni multiflori radix (PMR) and Cynanchi wilfordii radix (CWR) were compared to identify an anti-oxidant and whitening agent source from nature. We conducted an investigation into the anti-oxidant activities of PMR and CWR ethanol extracts by measuring total polyphenol content, total flavonoid content, and ABTS radical capacity. The total polyphenol contents of PMR and CWR were 17.310.54 mg GA/eq g, and 2.750.22 mg GA/eq g, respectively. The total flavonoid contents of PMR and CWR were 6.380.39 mg naringine/eq g, and 1.340.09 mg naringine/eq g, respectively. The 2,2`-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical decolorization of PMR and CWR were 96.890.21% at 1 mg/mL and 93.490.76% at 50 mg/mL. Melanoma cells were cultured with the PMR and CWR ethanol extracts for 48 hr, and total melanin content as a final product and the activity of tyrosinase, a key enzyme, in melanogenesis, were estimated. The PMR and CWR ethanol extracts increased melanin content and tyrosinase activity in a dose-dependent manner. These results suggest that PMR and CWR ethanol extracts could be useful as a skin whitening agent.