title: Antimelanogenic effect of ginsenoside Rg3 through extracellular signal-regulated kinase-mediated inhibition of microphthalmia-associated transcription factor.
abstract: BACKGROUND
  Panax ginseng has been used to prolong longevity and is believed to be useful for improving skin complexion. Ginsenosides are the most active components isolated from ginseng, and ginsenoside Rg3 (G-Rg3) in particular has been demonstrated to possess antioxidative, antitumorigenic, and anti-inflammatory properties. The aim of this study was to examine the ability of G-Rg3 to inhibit melanogenesis.
  
  
  METHODS
  The effects of G-Rg3 on melanin contents and the protein levels of tyrosinase, microphthalmia-associated transcription factor (MITF), and tyrosinase-related protein 1 (TRP1) were evaluated. Melanogenesis-regulating signaling molecules such as Akt and extracellular signal-regulated kinase (ERK) were also examined to explore G-Rg3-induced antimelanogenic mechanisms.
  
  
  RESULTS
  G-Rg3 was found to significantly inhibit the synthesis of melanin in normal human epidermal melanocytes and B16F10 cells in a dose-dependent manner. The activity of cellular tyrosinase and the expression of MITF, tyrosinase, and TRP1 were all reduced, whereas ERK was strongly activated. PD98059 (a specific inhibitor of ERK) attenuated the G-Rg3-induced inhibition of melanin synthesis and tyrosinase activity.
  
  
  CONCLUSIONS
  Taken together, these results showed that G-Rg3 induces the activation of ERK, which accounts for its antimelanogenic effects. G-Rg3 may be a promising safe skin-whitening agent, adding to the long list of uses of P. ginseng for the enhancement of skin beauty.
authors.affiliation: CleanUp Dermatologic Clinic, Seoul, Korea.
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sung Eun
authors.initials: SE
authors.lastname: Chang
authors.affiliation: Department of Dermatology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Ga-Young
authors.initials: GY
authors.lastname: Lee
keywords: Panax ginseng; antimelanogenic effect; ginsenoside Rg3