Bovistol B, bovistol D and strossmayerin: Sesquiterpene metabolites from the culture filtrate of the basidiomycete Coprinopsis strossmayeri

Basidiomycete fungi are a rich source of natural products with a diverse array of potentially
exploitable bioactivities. Two dimeric sesquiterpenes, bovistol B (1) and D (2), and one
monomeric sesquiterpene, strossmayerin (7), were isolated from the culture filtrate of the
basidiomycete fungus Coprinopsis strossmayeri. The structures were determined through a
combination of MS and 1D/2D NMR spectroscopic techniques. Likely monomeric precursors,
identified on the basis of HRMS analysis, allow a plausible biosynthetic pathway to be
proposed for the biosynthesis of 1 and 2, involving the dimerisation of the monomer through
a hetero-Diels-Alder mechanism. A gene cluster, including a putative sesquiterpene 1–11
cyclase, was identified through phylogenetic and RNA-seq analysis, and is proposed to be
responsible for the biosynthesis of 1 and 2.