Melanogenesis regulatory activity of the ethyl acetate fraction from Arctium lappa L. leaf on α-MSH–induced B16/F10 melanoma cells

Phenolics obtained from plants as natural compounds have been used in cosmetic industry as potential alternatives to synthetic chemicals due to its excellent antioxidant and whitening effects. This study investigated the possibility of using Arctium lappa L. leaf extracts as cosmetic substances by assessing whitening effects through its antioxidant and physiological activity in B16/F10 melanoma cells. The ethyl acetate fraction from Arctium lappa L. leaf showed the highest total phenolics (216.75 mg gallic acid equivalent (GAE)/g) relative to the other fractions (n-hexane, chloroform, and distilled water). The antioxidant activities of EAFA were evaluated based on 2,2′-azino-bis (3-ethyl benzthiazoline-6-sulfonic acid) diammonium salt (ABTS) /α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing/antioxidant power (FRAP), and malondialdehyde (MDA) inhibitory effects. The whitening effects of EAFA were examined using tyrosinase inhibitory activity and inhibition of α-melanocyte stimulating hormone (α-MSH) -induced melanogenesis in B16/F10 cells. The ethyl acetate fraction from Arctium lappa L. leaf effectively inhibited the tyrosinase activity and decreased melanin contents as following α-MSH stimulation. Based on these results, the inhibitory mechanism of melanogenesis was confirmed by measuring phosphorylated c-Jun N-terminal kinase (p-JNK), microphthalmia-associated transcription factor (MITF), tyrosinase-related protein 1 (TRP-1), and tyrosinase in α-MSH–induced B16/F10 cells. The ethyl acetate fraction from Arctium lappa L. leaf downregulated the levels of p-JNK, MITF, TRP-1, and tyrosinase. Finally, the main compounds of EAFA were analyzed using the ultra-performance liquid chromatography-quadrupole-time-of-flight (UPLC Q-TOF) MS system, and the components were identified as follows: trans-5-caffeoylqunic acid, rutin, kaempferol-3-O-rutinoside, 3,5-di-O-caffeoylqunic acid, and 4,5-di-O-caffeoylqunic acid.