Xerocomorubin is a pigment from the fungus order Boletales.
It is the oxidized form of isoxerocomic acid.
Synthesis experiments have shown tetra-acetylation by acetic anhydride and sulfuric acid.
Although xerocomorubin and variegatorubin give off the same deep red color and could simultaneously occur in a mushroom, extracts from the deep red colored mushroom Boletus rubellus Krombh.
identified only variegatorubin by thin layer chromatography (TLC), leading to the question the natural abundance of xerocomorubin.