The root of Vitis amurensis Ruprecht, a sort of wild-growing grape, has been used in oriental medicine for treatment of skin ailments; however, its dermatological activity is not sufficiently understood. The aim of this study was to investigate tyrosinase inhibitory and anti-melanogenic activities of V. amurensis Ruprecht root methanol extract (VARM) in B16F10 mouse melanoma cells and to attempt to isolate and identify the active compound issued from VARM.

Anti-melanogenic activity of VARM was analyzed in α-melanocyte stimulating hormone (MSH)-stimulated B16F10 cells through evaluation of antioxidative activity as well as inhibited tyrosinase activity and melanin contents compared with those of kojic acid and arbutin. After anti-melanogenic analysis of VARM, serial fractionation, nuclear magnetic resonance (NMR), and thin layer chromatorgraphy (TLC) were applied for identification of active compounds contained in VARM.

VARM significantly inhibited oxidative stress and tyrosinase activity and attenuated α-MSH-induced melanin production in B16F10 cells. For isolation of active compounds, VARM was fractionated using a series of organic solvents, including dichloromethane (CH₂Cl₂), ethyl acetate (EtOAc), and n -butanol ( n -BuOH). Among fractions showing anti-melanogenic activity, the CH₂Cl₂ fraction induced the most potent attenuation of melanogenesis without cytotoxicity and the major compound in the CH₂Cl₂ fraction was identified as betulinic acid. Betulinic acid isolated from the CH₂Cl₂ fraction of VARM significantly attenuated α-MSH-induced melanogenesis in a dose dependent manner, which was stronger than that of arbutin used as a positive control.

These results indicate that VARM inhibits oxidative stress, tyrosinase activity, and α-MSH-induced melanogenesis in B16F10 cells, due primarily to the active compound, betulinic acid, in the CH₂Cl₂ fraction.