Flavokawains B and C, melanogenesis inhibitors, isolated from the root of Piper methysticum and synthesis of analogs

Bioorg Med Chem Lett. 2015 Feb 15;25(4):799-802. doi: 10.1016/j.bmcl.2014.12.082. Epub 2015 Jan 3.


The ethanolic extract of the root of Piper methysticum was found to inhibit melanogenesis in MSH-activated B16 melanoma cells. Flavokawains B and C were isolated from this extract based on their anti-melanogenesis activity and found to inhibit melanogenesis with IC50 values of 7.7μM and 6.9μM, respectively. Flavokawain analogs were synthesized through a Claisen-Schmidt condensation of their corresponding acetophenones and benzaldehydes and were evaluated in terms of their tyrosinase inhibitory and anti-melanogenesis activities. Compound 1b was the most potent of these with an IC50 value of 2.3μM in melanogenesis inhibition assays using MSH-activated B16 melanoma cells.

Keywords: Chalcones; Flavokawain B and C; Melanogenesis; Piper methysticum.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Flavonoids / chemical synthesis
  • Flavonoids / chemistry*
  • Flavonoids / pharmacology*
  • Humans
  • Kava / chemistry*
  • Melanins / antagonists & inhibitors*
  • Melanins / biosynthesis
  • Melanins / chemical synthesis
  • Melanoma, Experimental / drug therapy
  • Mice
  • Structure-Activity Relationship


  • Flavonoids
  • Melanins
  • flavokawain B