Inhibitory effect of Prunus persica flesh extract (PPFE) on melanogenesis through the microphthalmia-associated transcription factor (MITF)-mediated pathway

Novel tyrosinase inhibitors are important for pigmentation in the skin. Following extraction of tyrosinase inhibitors from edible vegetables or fruits, we found that the Prunus persica flesh extract (PPFE) exhibited potential inhibitory activity for melanogenesis. PPFE showed tyrosinase inhibitory activity in an enzymatic assay and PPFE also significantly inhibited the melanin formation in cultured mouse melan-a cells. Moreover, real-time RT-PCR analysis revealed that the inhibition of melanin production by PPFE was closely related to marked suppression of mRNA expression of tyrosinase and tyrosinase-related protein-1 and -2 (TRP-1 and TRP-2) in melan-a cells. Further investigation found that the modulation of tyrosinase expression by PPFE was associated with the transcriptional regulation of the microphthalmia-associated transcription factor (MITF). PPFE inhibited the promoter activity of MITF and suppressed MITF mRNA expression in melan-a cells. These results indicate that PPFE down-regulates melanogenesis-associated gene expression through MITF-mediated transcriptional regulation and these events might be related to the hypopigmentary effects of PPFE.