New terpenoids from the fermentation broth of the edible mushroom <i>Cyclocybe aegerita</i>

Abstract

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 3 J H,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.