Effect of Hydroxycinnamic Acid Derivatives from Corn Bran on Melanogenic Protein Expression

A recent study has demonstrated that polyamine conjugates from corn (Zea may L.) bran and related hydroxycinnamic acids have antioxidant and antimelanogenic activities. To verify the ability of hydroxycinnamic acid derivatives (HCAD) from corn bran to reduce skin pigmentation as cosmetic active ingredients, we assessed the effect on melanogenic proteins expression in murine B16 melanoma cells and on skin pigmentation levels in clinical trials. We investigated the effect of HCAD on melanogenic protein expression using Western blot analysis. Furthermore, we assessed the effects of a cream containing 0.1% by weight corn bran extract (CBE) with HCAD such as N,N`-dicoumaroylputrescine, N-p-coumaroyl-N`-feruloylputrescine and N,N`-diferuloylputrescine in clinical trials. HCAD reduced the forskolin-induced increase in melanin content of cultured melanoma cells. To elucidate the effect of HCAD on melanogenesis, we performed a Western blot analysis of melanogenic proteins, such as tyrosinase, tyrosinase-related protein (TRP)-1, TRP-2 and microphthalmia-associated transcription factor (MITF). HCAD reduced levels of tyrosinase and MITF, however, it did not change TRP-1 and TRP-2 levels. The 0.1% CBE cream significantly reduced skin pigmentation with no irritation. The present study indicates that HCAD have good potential to be useful antimelanogenic agents.