Hosta longipes inhibits melanogenesis by reducing expression of the melanocortin 1 receptor

Background Hosta longipes is a traditional folk medicine that has been used to treat otitis media, inflammation, skin ulcers, and snake bites for a long time. Several phytochemicals isolated from H. longipes exhibit cytotoxic activity against cancer cells or anti-neuroinflammatory effects against microglial cell lines. However, studies on their physiological activity have been relatively few. Objective The goal of this study was to investigate a new role for H. longipes in the skin, and we characterized its inhibitory effects on melanin biosynthesis. Results In this study, we confirmed that pigmentation in alpha-melanocyte stimulating hormone-induced B16F10 cells and zebrafish was ameliorated by the addition of H. longipes ethanol extract (HLE) and that the hexane (Hx) fraction had a better whitening effect than any other fraction. The active two compounds isolated from the Hx fraction were identified as linolenic acid and linoleic acid. HLE, the Hx fraction, and two compounds inhibited melanin formation by blocking the melanocortin 1 receptor signaling. Conclusion Taken together, the potential for antimelanogenesis by HLE will provide insight into the development of new skin-whitening products for photodamaged skin.