Injury‐Triggered Blueing Reactions of Psilocybe “Magic” Mushrooms

When psilocybin-producing mushrooms are injured, they turn blue due to a two-step enzymatic cascade. The phosphatase PsiP removes a phosphate group from psilocybin to yield psilocin, and the enzyme PsiL oxidizes psilocin's 4-hydroxy group. This oxidation triggers the formation of blue oligomers, primarily linked at carbon-5, as shown by carbon-13 NMR. Mass and infrared spectroscopy reveal a mixture of psilocyl chains ranging from 3 to 13 units long, with multiple pathways depending on oxidant strength and substrate concentration. The findings suggest that psilocybin's phosphate group acts as a reversible protective modification, preventing premature bluing until injury occurs.

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Abstract

Abstract Upon injury, psychotropic psilocybin‐producing mushrooms instantly develop an intense blue color, the chemical basis and mode of formation of which has remained elusive. We report two enzymes from Psilocybe cubensis that carry out a two‐step cascade to prepare psilocybin for oxidative oligomerization that leads to blue products. The phosphatase PsiP removes the 4‐ O ‐phosphate group to yield psilocin, while PsiL oxidizes its 4‐hydroxy group. The PsiL reaction was monitored by in situ 13 C NMR spectroscopy, which indicated that oxidative coupling of psilocyl residues occurs primarily via C‐5. MS and IR spectroscopy indicated the formation of a heterogeneous mixture of preferentially psilocyl 3‐ to 13‐mers and suggest multiple oligomerization routes, depending on oxidative power and substrate concentration. The results also imply that phosphate ester of psilocybin serves a reversible protective function.