Chemical constituents of Ruta graveolens L. and their melanogenic effects and action mechanism.

Ruta graveolens L. has been widely used to treat various skin ailments, especially vitiligo. In this study, we isolated a new furanocoumarin named Rutagrarin (1) along with 14 known compounds (2-15) from the aerial parts of R. graveolens and elucidated their chemical structures via various spectroscopy. We found that compound 5 promoted melanogenesis and tyrosinase activity in B16 cells. Further investigation on underlying mechanisms revealed that compound 5 activated the transcription of microtia-related transcription factors and promoted the production of melanin in B16 cells via the Akt/GSK-3β/β-catenin pathway. Therefore, we confirmed the traditional efficacy of R. graveolens and speculated that compound 5 could be used as a natural drug to treat vitiligo.