Melanin protects the skin against ultraviolet radiation by scattering incoming light and absorbing diverse
free radicals. Agents that increase
melanin synthesis in melanocytes may reduce the risk of photodamage and
skin cancer. The present study investigated the effect of a
methanol extract of Ardisia crenata (AC) on melanogenesis in B16F10 cells. Treatment of cultured B16F10 cells with AC extract (10, 20 and 40 µg/ml) stimulated an increase in
melanin levels in a concentration-dependent manner, without cytotoxicity.
Tyrosinase is key in the regulation of
melanin production, thus the effect of AC extract on
tyrosinase activity and
protein expression was analyzed. AC extract was observed to significantly increase
tyrosinase activity and
protein expression in B16F10 cells. Furthermore, AC extract was found to markedly increase the
protein expression of
microphthalmia-associated transcription factor, which is an important
transcription factor involved in
tyrosinase gene expression. In addition, AC extract (40 µg/ml) was observed to suppress the activation of
extracellular signal-regulated kinase (ERK) and Akt, which negatively regulate
melanin synthesis in B16F10 cells. In conclusion, to the best of our knowledge, the present study is the first to show that a
methanol extract of AC stimulates melanogenesis by increasing
tyrosinase expression via the inhibition of ERK and Akt. Thus,
methanol extract of AC may be a potential treatment for
hypopigmentation diseases and may be a candidate for skin-tanning cosmetic products.