• Tyrosinase;
  • Eumelanin;
  • Pheomelanin;
  • Glycosylation;
  • Inhibitors;
  • EV;
  • Pheo;
  • Glycosyl

Recent elucidation of regulatory mechanisms of eu- and pheomelanogenesis has led us towards an exciting new era of melanogenesis control. I will chiefly address our progress on inhibitory control of melanogenesis from the macromolecular level to human skin colour.

In the past, the exploration and search for skin depigmenting agents has been focussed on and initiated from substances which can suppress isolated tyrosinase in vitro. Now, as I have classified below, many new melanogenic inhibitors have been discovered which, in spite of their non-suppressive effect on isolated naked tyrosinase, suppress melanin formation in the living pigment cell in vitro as well as in the natural world. I will also discuss a recently found unique disorder: unilateral suppression of mixed melanogenesis.

  • I. 
    Isolated tyrosinase: Suppressive type
  • 1
    Chemical inhibitors, e.g., kojic acid, ascorbic acid
  • 2
    Naturally occurring inhibitors, e.g., indole blocking factor
  • II. 
    Isolated tyrosinase: Nonsuppressive type
  • 3
    Inhibition of tyrosinase synthesis in ribosome
  • 4
    Inhibition of tyrosinase transfer to premelanosomes by glycosylation interruption, e.g., tunicamycin, glucosamine
  • 5
    Melanocyte cytotoxic inhibitors, e.g., hydroquinone, azelaic acid
  • III. 
    Congenital unilateral suppression of human mixed melanogenesis
  • 6
    Congenital pheomelanic macular depigmentation