Abstract 2-Hydroxytyrosol (2-HT), originally reported as a synthetic compound, was isolated for the
first time as a fungal metabolite. 2-HT was found to inhibit mushroom tyrosinase with an IC50 value of
13.0 mmol/L. Furthermore, 2-HT dose-dependently inhibited tyrosinase activity (IC50, 32.5 mmol/L) in the
cell-free extract of B16 melanoma cells and α-melanocyte stimulating hormone (α-MSH)-stimulated
melanin formation in intact B16 melanoma cells.