New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita

The strophariaceous basidiomycete Cyclocybe aegerita (synonyms Agrocybe aegerita and A. cylindracea) is one of the most praised cultivated edible mushrooms and is being cultivated at large scale for food production. Furthermore, the fungus serves as a model organism to study fruiting body formation and the production of secondary metabolites during the life cycle of Basidiomycota. By studying the secondary metabolite profiles of C. aegerita, we found several terpenoids in submerged cultures. Aside from the main metabolite, bovistol (1), two new bovistol derivatives B and C (2, 3) and pasteurestin C as a new protoilludane (4) were isolated by preparative HPLC. Their structures were elucidated by mass spectrometry and NMR spectroscopy. The relative configurations of 2-4 were assigned by ROESY correlations, and 3JH,H coupling constants in the case of 4. Applying quantitative PCR for gene expression validation, we linked the production of bovistol and its derivatives to the respective biosynthesis gene clusters.