Melanogenesis-Promoting Effects of Sophora japonica Methanol Extract in Mean-a Cells

The flowers and flower buds of Sophora japonica are well-known traditional Chinese medicinal herbs. Pharmacologic studies and cases from clinical practices have demonstrated that S. japonica has anti-tumor, anti-fertility, and anti-cancer activities. The active constituents of the herb are also known to be the flavonoid components. The melanogenic effects of S. japonica methanol extract (SJME) were evaluated in melan-a cells, which are immortalized cells derived from C57BL/6 mice. The maximum permissible level of SJME in melan-a cells was over 200 μg/mL. Additionally, SJME stimulated melanin synthesis, as well as tyrosinase activity, in a dose-dependent manner. Furthermore, the melanogenic effect of SJME was greater than that of IBMX, a well-known pigmenting agent. Lastly, SJME treatments at concentrations between 6.25 and 50 μg/mL increased tyrosinase messenger RNA expression. Collectively, these results suggested that SJME enhanced melanogenesis through an interaction with tyrosinase at the transcriptional level.