text: Marmesin (nodakenetin) is a chemical compound precursor in psoralen and linear furanocoumarins biosynthesis.
  Marmesin plays a central role in the biosynthesis of furocoumarins in the plant ruta graveolens, more commonly known as rue. It acts as the natural intermediate in the formation of the furan ring that leads to a 4’,5’-dihydro furocoumarin-derivative. This substance can then be transformed into psoralen and other furocoumarins present in rue. Upon feeding the herb a dose of marmesin, radioactivity became strongly incorporated into psoralen and thus the plant itself.