Identification of sake extract as a new anti-melanogenic ingredient by in vitro and clinical trials.

Overproduction of melanin is the cause of skin hyperpigmentation, which is related to several skin diseases and cosmetic concerns. Sake is a Japanese alcoholic beverage produced from rice and water by fermentation, but is little known for its effect on melanogenesis. To identify the effect of sake extract on melanin synthesis, a melanin assay was performed in melan-A murine melanocytes. Sake extract treatment significantly inhibited melanin production in a dose-dependent manner, and tyrosinase, the rate-limiting enzyme of melanogenesis, decreased significantly at the protein level. Further investigations were performed with multiple assay systems; a sake extract reduced melanin production in melan-A/SP-1 murine cell co-culture, and also in MelanoDerm, a skin equivalent model of human keratinocytes-melanocytes. Finally, subjects were treated with a formula containing the sake extract. Topical application of the sake extract product improved skin lightness (L*) significantly within 7 days. We identified sake extract as a new anti-melanogenic ingredient through in vitro and in vivo experiments. These results suggest that a sake extract can be used to improve skin hyperpigmentation.