Depigmenting effect of alpha-tocopheryl ferulate on normal human melanocytes

Oral vitamin E supplementation has been reported to improve facial hyperpigmentation. alpha-Tocopheryl ferulate (alpha-TF) is a compound of alpha-tocopherol (alpha-T) and ferulic acid connected by an ester bond. Ferulic acid is also an antioxidant, and could scavenge free radicals induced by ultraviolet (UV) radiation, and thus maintain the long-lasting antioxidative effect of alpha-T. Previously we have reported that alpha-TF inhibited melanogenesis in human melanoma cells. To know whether alpha-TF might be useful as a whitening agent to improve and prevent facial hyperpigmentation, the depigmenting effect of alpha-TF in normal human melanocytes was examined in this study. The results showed that 30 microg/ml of alpha-TF dissolved in 150 microg/ml of lecithin inhibited melanization significantly without inhibiting cell growth. This phenotypic change was associated with the inhibition of tyrosinase and the degree of inhibition was dose dependent. No significant effect on DOPAchrome tautomerase (DT) activity was observed. These results suggest that alpha-TF is a candidate for an efficient whitening agent which suppresses melanogenesis. In this paper, the role of alpha-T and alpha-TF in inhibiting biological reactions induced by reactive oxygen species (ROS) is also discussed.