Communiols E−H:  New Polyketide Metabolites from the Coprophilous Fungus Podospora communis

Abstract

Communiols E-H (1-4), four new polyketide-derived natural products containing furanocyclopentane, furanocyclopentene, cyclopentene, or γ-lactone moieties, have been isolated from two geographically distinct isolates of the coprophilous fungus Podospora communis. The structures of these compounds were determined by analysis of NMR and MS data.

Chemical investigations of fungicolous and coprophilous fungi

“…HMBC data confirmed that the remainder of the structure of 7.8 matched that of 7.7, with the stereochemical assignment presumed to be analogous to that of 7.7. these compounds. [196][197][198][199][200][201][202][203] Communiols I -O (7.3 -7.9) contain the same skeleton and share similar presumed polyketide biogenetic origins with the other known communiols. Interestingly, this relatively simple, highly reduced group of eleven-carbon compounds has few particularly close analogues and is thus far known only from Podospora spp.…”

“…Our preliminary investigations of coprophilous fungi have afforded a variety of new secondary metabolites, many of which show antibacterial or antifungal properties. [193][194][195][196][197] The genus Podospora has been of interest in our research due to the limited number of chemical studies of this taxonomic group that have been reported, despite its widespread occurrence and literature describing more than 80 named species. 94 Preliminary results obtained in our earlier work on a few selected members of this genus have been particularly fruitful, suggesting that more studies of these fungi as sources of new bioactive natural products would be worthwhile.…”

“…Communiols A -H are a series of polyketide-derived metabolites originally reported by members of our research group from a horse dung isolate of the coprophilous fungus Podospora communis collected in northern California. 196,197 All but one of these compounds share an 11-carbon skeleton with various modifications leading mostly to 2,4-disubstituted tetrahydrofuran-containing products. 196,197 Their structures, in conjunction with their antibacterial properties, have triggered synthetic efforts toward the synthesis of this series of compounds.…”

“…196,197 All but one of these compounds share an 11-carbon skeleton with various modifications leading mostly to 2,4-disubstituted tetrahydrofuran-containing products. 196,197 Their structures, in conjunction with their antibacterial properties, have triggered synthetic efforts toward the synthesis of this series of compounds. [198][199][200][201][202][203] As a result, total synthesis of communiols A -F and H has been accomplished by three independent research groups, and an aspect of the original stereochemical assignment that had been made based on an empirical rule was revised.…”

“…Interestingly, this relatively simple, highly reduced group of eleven-carbon compounds has few particularly close analogues and is thus far known only from Podospora spp. 196,197 Although the major components, communiols B and C, show antibacterial effects against [212][213][214] Other members of this group (e.g., militarinones) lack the ether linkage, and, in some instances, the pyridone unit is replaced by a tetramic acid moiety. 215,216 As is the case with funiculosin, some of these metabolites have been reported to show antifungal activity.…”