[6]-Shogaol inhibits α-MSH-induced melanogenesis through the acceleration of ERK and PI3K/Akt-mediated MITF degradation

Biomed Res Int. 2014:2014:842569. doi: 10.1155/2014/842569. Epub 2014 Jun 19.

Abstract

[6]-Shogaol is the main biologically active component of ginger. Previous reports showed that [6]-shogaol has several pharmacological characteristics, such as antioxidative, anti-inflammatory, antimicrobial, and anticarcinogenic properties. However, the effects of [6]-shogaol on melanogenesis remain to be elucidated. The study aimed to evaluate the potential skin whitening mechanisms of [6]-shogaol. The effects of [6]-shogaol on cell viability, melanin content, tyrosinase activity, and the expression of the tyrosinase and microphthalmia-associated transcription factor (MITF) were measured. The results revealed that [6]-shogaol effectively suppresses tyrosinase activity and the amount of melanin and that those effects are more pronounced than those of arbutin. It was also found that [6]-shogaol decreased the protein expression levels of tyrosinase-related protein 1 (TRP-1) and microphthalmia-associated transcriptional factor (MITF). In addition, the MITF mRNA levels were also effectively decreased in the presence of 20 μM [6]-shogaol. The degradation of MITF protein was inhibited by the MEK 1-inhibitor (U0126) or phosphatidylinositol-3-kinase inhibitor (PI3K inhibitor) (LY294002). Further immunofluorescence staining assay implied the involvement of the proteasome in the downregulation of MITF by [6]-shogaol. Our confocal assay results also confirmed that [6]-shogaol inhibited α-melanocyte stimulating hormone- (α-MSH-) induced melanogenesis through the acceleration of extracellular responsive kinase (ERK) and phosphatidylinositol-3-kinase- (PI3K/Akt-) mediated MITF degradation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Catechols / administration & dosage*
  • Cell Survival / drug effects
  • Enzyme Inhibitors / administration & dosage*
  • Melanins / antagonists & inhibitors
  • Melanins / metabolism
  • Melanoma, Experimental / drug therapy*
  • Melanoma, Experimental / genetics
  • Melanoma, Experimental / metabolism
  • Mice
  • Microphthalmia-Associated Transcription Factor / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proteolysis / drug effects
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / drug effects
  • Signal Transduction / drug effects
  • alpha-MSH / metabolism*

Substances

  • Catechols
  • Enzyme Inhibitors
  • MITF protein, human
  • Melanins
  • Microphthalmia-Associated Transcription Factor
  • RNA, Messenger
  • alpha-MSH
  • shogaol
  • Phosphatidylinositol 3-Kinases