Constituents of Agaricus xanthodermus Genevier: the first naturally endogenous azo compound and toxic phenolic metabolites.

Extraction of fresh sporophores of the fungus Agaricus xanthodermus yields 4,4'-dihydroxy-azobenzene, phenol, p-quinol, and 4,4'-dihydroxybiphenyl. This is the first report of an azo compound arising endogenously in nature, while phenol, p-quinol and 4,4'-dihydroxybiphenyl have not previously been isolated from higher fungi. Phenol is present in fruitbodies in sufficiently high concentration to account for the toxicity of A. xanthodermus.