Assessment of the Effect of Arbutin Isomers and Kojic Acid on Melanin Production, Tyrosinase Activity, and Tyrosinase Expression in B16-4A5 and HMV‐II Melanoma Cells

The inhibitory effects of α-arbutin, β-arbutin, and kojic acid on melanogenesis, tyrosinase activity, and tyrosinase protein expression in mouse melanoma cells (B16-4A5) and human melanoma cells (HMV‐II) were directly compared. β-Arbutin showed a stronger inhibitory effect on melanogenesis and tyrosinase expression in B16-4A5 cells than α-arbutin and kojic acid. Kojic acid showed a stronger inhibitory effect on mushroom and B16-4A5 tyrosinase activity than α-arbutin and β-arbutin. In contrast, kojic acid inhibited all of these effects more strongly than α-arbutin or β-arbutin in HMV‐II cells. These results suggest that kojic acid may be used as a positive control for the inhibitory melanogenesis assay, and for tyrosinase activity and tyrosinase expression assays that use HMV‐II cells. Moreover, using HMV‐II cells with kojic acid as the positive control may facilitate the search for new skin-whitening agents using natural products and provide an alternative to the B16-4A5 assay.