Whitening Effects of Angelica dahurica Radix Ethanol Extract in Brown Guinea Pig and Melan-a Cell

Abstract

The whitening effect of Angelica dahurica Radix ethanol extract (ADEE) was investigated with in vitro and in vivo tests. For in vitro tests, ADEE was treated at concentrations of 6.25, 12.5, 25, and 50 μg/mL to melan-a cells in order to evaluate ADEE’s inhibitory effects on melanin synthesis and tyrosinase activity. Arbutin was used as positive control. For in vivo tests, the test agent was topically applied to hyperpigmented areas on the back skins of brown guinea-pigs (weight: 450~500 g). The hyperpigmented areas were generated by 1,500 mJ/cm of ultraviolet B (UVB) irradiation. The test agent of 30 μL was applied twice a day, five days a week, for five weeks. The animals were divided into 6 groups: normal (N), control (C), vehicle control (VC), positive control (PC, 2% hydroquinone), experimental 1 (E1, 1% ADEE) and experimental 2 (E2, 2% ADEE). ADEE effectively inhibited melanin synthesis and tyrosinase activity of melan-a cells in a dose-dependent manner. The pigmentation of brown guinea-pigs was clearly lightened in the PC, E1 and E2 groups compared to the C and VC groups. At the fifth week, the melanin indices of the ADEE groups were significantly lower (p⁄0.00l) than that of the VC group. Visual and quantitative analyses revealed that the degree of melanin pigmentation and S-100 protein expression levels were significantly decreased (p⁄0.00l) in ADEE treated groups compared to