Pentagalloylglucose Inhibits Melanogenesis via Suppression of MITF Signaling Pathway

Pentagalloylglucose (PGG) is a powerful antioxidant and a naturally derived polyphenolic compound present in tannins. In this study, we investigated the ability of PGG to selectively inhibit hyperpigmentation through the regulation of melanogenesis in melanocytes. PGG inhibited melanin production in α-melanocyte-stimulating hormone (α-MSH)-induced B16F10 melanoma cells. Furthermore, PGG suppressed the expression of melanin synthesis enzymes, such as tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2. The mRNA and protein expression of the microphthalmia-associated transcription factor, which is involved in the mechanism of melanogenesis, was also reduced by PGG, and this effect was induced via PKA/CREB and MAPK phosphorylation. These results suggest that PGG inhibits α-MSH-induced melanin production by regulating the PKA/CREB/MAPK signaling pathway, indicating that natural compounds can serve as inhibitors of melanogenesis.