Antimelanogenic and antioxidative effects of residual powders from Shochu distillation remnants

Shochu distillation remnants (SDR) are by-products in the manufacturing process of the Japanese liquor Shochu and include various useful organic compounds derived from the fermentation of grains. In this study, we investigated the inhibitory effects of barley-, black rice-, rice-, and sweet potato-powder from Shochu distillation remnants (PSDR) on the melanogenesis of B16 cells. Barley- and black rice-PSDR showed significant decrease in the intracellular melanin content and tyrosinase activity without cytotoxicity in the concentration range of 500–1000 μg/mL. Significantly, the antioxidative capacity of PSDR correlated well with the antimelanogenesis on the basis of a radical-scavenging assay. Furthermore, some antioxidant polyphenols in PSDR were identified by HPLC and the amount of the polyphenols was in good agreement with the antimelanogenic effects of PSDR. These results indicated that the polyphenols are the active components of PSDR for the antimelanogenesis of B16 cells. This study suggests that barley- and black rice-PSDR could be novel antimelanogenic materials for skin whitening.