Cadopherone and colomitide polyketides from Cadophora wood-rot fungi associated with historic expedition huts in Antarctica

• Published in: Phytochemistry (Oxford) Vol. 148; pp. 1 - 10
• Main Authors: Rusman, Yudi, Held, Benjamin W., Blanchette, Robert A., He, Yanan, Salomon, Christine E.
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 01.04.2018; Elsevier
• Subjects: Biochemistry & Molecular Biology; Cadopherone; Cadophora; Colomitide; Fungus; Life Sciences & Biomedicine; PKS; Plant Sciences; Polyketide; Science & Technology; Similin; Spiciferone; Polyketide; Fungus; Cadophora; Colomitide; PKS; Spiciferone; Cadopherone; Similin; SURVIVAL; RAPID COLORIMETRIC ASSAY; BEETLE; BIOACTIVE METABOLITES; BIOSYNTHESIS; GROWTH; DIVERSITY; COCHLIOBOLUS-SPICIFER; PHYTOPATHOGENIC FUNGUS
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2017.12.019

Recent investigations of filamentous fungi isolated from coastal areas and historic wooden structures in the Ross Sea and Peninsula regions of Antarctica have identified the genus Cadophora as one of the most abundant fungal groups, comprising more than 30% of culturable fungi at some locations. A methanol extract of Cadophora luteo-olivacea grown on rice media yielded the known polyketides spiciferone A, spiciferol A, dihydrospiciferone A and dihydrospiciferol A. Additionally, nine related hexaketides were identified, including spiciferone F, two isomers of the known fungal bicyclic ketal colomitide B, cadopherones A-D, similin C, and spicifernin B. HPLC and NMR analysis of extracts from other isolates collected in Antarctica suggests that the spiciferones and colomitides are produced by at least two different Cadophora species. Preliminary precursor feeding experiments provided evidence for the biosynthesis of the colomitides from the same polyketide pathway as the spiciferone phytotoxins, possibly via a type III polyketide synthase (PKS). None of the compounds were active in a panel of anti-bacterial, anti-fungal, and mammalian cytotoxicity assays. Cadophora species of fungi are common in polar environments and cause a soft rot form of wood decay in historic expedition huts in the Ross Sea, historic structures on Deception Island, and on the Peninsula of Antarctica. [Display omitted] •Nine hexaketides and four known analogs were isolated from Cadophora luteo-olivacea.•Stable isotope feeding studies were used to predict a Type III PKS biosynthetic pathway.•The compounds were not inhibitory against mammalian cells, or bacterial or fungal pathogens.•Spiciferones and colomitides were also identified from C. malorum collected from Antarctica.