Biol. Pharm. Bull. 30(10) 1972—1974 (2007)

color and plays an important role in the prevention of suninduced skin injury. Melanin biosynthesis proceeds through a complex series of enzymatic and chemical reactions in melanocytes. Synthesis of melanin starts from the conversion of the amino acid L-tyrosine to dopaquinone by tyrosinase, the enzyme catalyzing the rate-limiting step for melanin biosynthesis. This tyrosinase process is involved in abnormal accumulation of melanin pigments (hyperpigmentation). Therefore, tyrosinase inhibitors such as kojic acid and albutin have been established as important constituents of cosmetic products and depigmenting agents for hyperpigmentation. Several new melanin biosynthesis inhibitors from plants have been reported in cultured B-16 mouse melanoma cells, such as N-feruloylserotonin, N-(p-coumaroyl)serotonin, acacetin, esculetin, and nobiletin. As part of efforts to discover phytochemicals with melanin biosynthesis inhibitory activity, we screened compounds isolated from Enicosanthum membranifolium SINCLAIR (Annonaceae) as melanin biosynthesis inhibitors. N-trans-feruloyltyramine (FA) showed potent inhibitory activity against melanogenesis in cultured B-16 mouse melanoma cells. This compound was also isolated from Enicosanthum cupulare (KING) AIRY-SHAW. To the best of our knowledge, this is the first report of the melanin biosynthesis inhibitory effects of FA.