Structure of preussomerin A: an unusual new antifungal metabolite from the coprophilous fungus Preussia isomera

Reports of interspecies competition among coprophilous (dung-colonizing) fungi have led us to investigate such organisms as potential sources of new, naturally occurring antifungal agents. During our investigations of the chemistry associated with these competitive effects, we have discovered a unique new antifungal metabolite from cultures of Preussia isomera Cain (CBS 415.82). P. isomera is an ascomycete that colonizes cattle dung and exhibits antagonistic activity toward other coprophilous fungi in vitro. We report here details of the isolation, identification, and biological activity of this new metabolite, which we have named preussomerin A.