Chromogenic Triterpenoids fromCortinarius fulvoincarnatus,C. sodagnitus and Related Toadstools (Agaricales)

Abstract

Fruit-bodies of the toadstools Cortinarius sodagnitus,C. fulvoincarnatus, C. arcuatorum(Agaricales) show a remarkable ink-red colour reaction when treated with aqueous base. We isolated six chromogens, named the sodagnitins A–F, from the toadstools and elucidated their structures by spectroscopic techniques. The sodagnitins are triterpenoids of the malabaricane type with a highly modified side chain. A mechanism for the colour reaction is proposed.