Effect of puerarin on melanogenesis in human melanocytes and vitiligo mouse models and the underlying mechanism

Puerarin is the major bioactive ingredient derived from the root of the Pueraria lobata (Willd.), and its antioxidative stress effects have been demonstrated in several previous studies. Moreover, Puerarin can upregulate melanin synthesis and microphthalmia-associated transcription factor (MITF) transcription by increasing cAMP level of intracellular cyclic adenosine monophosphate. Vitiligo is an acquired cutaneous disorder of pigmentation, and the pathogenesis has remained elusive. Current treatment modalities are directed towards achieving repigmentation. In this study, we found that after treating with puerarin at various concentrations of 40 μmol/L, the melanin content of human melanocytes increased significantly and the apparent level of protein and the RNA levels of MITF, tyrosinase (TYR), and tyrosinase-related protein 1 (TRP-1) were also increased. Further, puerarin was shown to inhibit phosphorylation and activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) without significantly affecting p38 and c-Jun N-terminal kinase phosphorylation. These results demonstrated that puerarin stimulated melanogenesis in human melanocytes via inhibition of ERK1/2 signaling pathways, which leads to upregulation of MITF and TYR as well as TRP-1 subsequently. Additionally, mice vitiligo models with puerarin treatment showed lighter pathological changes. Therefore, we suggested that puerarin might be a potential medicine for vitiligo.