 The identity of the chemical causing bluing upon tissue injury was reported in 1973. The molecule, gyrocyanin, is a highly oxidized bis-phenol-substituted cyclopentenone that develops a blue color when it is oxidized. In contrast, the bluing of other boletes has been attributed to the oxidation of variegatic or xerocomic acid. Gyrocyanin is biosynthesized from intermediates supplied by the shikimate pathway, a metabolic route used by fungi for the synthesis of aromatic amino acids.
