Strobiloscyphones A–F, 6-Isopentylsphaeropsidones and Other Metabolites from Strobiloscypha sp. AZ0266, a Leaf-Associated Fungus of Douglas Fir

Abstract

Six new 6-isopentylsphaeropsidones, strobiloscyphones A–F (1–6), and a new hexadecanoic acid, (2Z,4E,6E)-8,9-dihydroxy-10-oxohexadeca-2,4,6-trienoic acid (7), together with sphaeropsidone (8) and its known synthetic analogue 5-dehydrosphaeropsidone (9) were isolated from Strobiloscypha sp. AZ0266, a fungus inhabiting the leaf litter of Douglas fir (Pseudotsuga menziesii). The structures of 1–7 were established on the basis of their high-resolution mass and 1D and 2D NMR spectroscopic data, and their relative and/or absolute configurations were determined by NOE, comparison of experimental and calculated ECD spectra, and application of the modified Mosher’s ester method. Of these, strobiloscyphone F (6) contains a novel highly oxygenated tetracyclic oxireno-octahydrodibenzofuran ring system. Natural products 1, 6, and 9 and the semisynthetic analogue 12 derived from 8 exhibited cytotoxic activity, whereas 9 and 12 showed antimicrobial activity. Possible biosynthetic pathways to 1–6, 8, and 9 are proposed.

Lachnuoic Acids A−F: Ambuic Acid Congeners from a Saprotrophic Lachnum Species

“…This suggestion was further confirmed by 13 NMR and HSQC spectral data of 2 (Table 1) that revealed relatively shielded carbon resonances at δ C 60.0, 64.2, 63.5 and 63.1 assigned to C-4, C-5, C-6 and C-9, respectively, compared to their counterparts in 1. The obtained results and by comparison with those reported of ambuic acid analogues [3][4][5][6] and conduritols, [7,8] compound 2 was suggested to have an epoxide ring formed over C-4 and C-5 accounting for the additional degree of unsaturation. Further confirmation of the suggested structure of 2 (Figure 1) was provided by 1 H-1 H COSY and HMBC spectra (Figure 2).…”

“…Based on the obtained results, compound 4 was deduced to incorporate a cyclohexenone moiety in its structure. A literature search of 4 revealed its structural resemblance to strobiloscyphones [4] and pestallic acids. [5] Further confirmation to the suggested structure of 4 was provided by HMBC spectrum (Figure 4 2, Figure S41) revealed two unprotonated carbon atoms, a carbonyl carbon at δ C 167.9 and an olefinic carbon at δ C 134.2 in addition to five protonated olefinic carbon atoms at δ C 118.7, 122.9, 133.9, 137.5 and 139.7 that account altogether for four degrees of unsaturation.…”

The Functional Biogeography of eDNA Metacommunities in the Post-Fire Landscape of the Angeles National Forest

“…sPLS was sensitive to outliers; results focused on a cluster of Green Trail samples with high elevation and longitude, shown in the top cluster of Figure 4. Analysis revealed the cluster included the post-fire pioneer fungus Pyronema [6,39], Tremella, and Strobiloscypha, which produce strobiloscyphone antimicrobials [40]. Chlorellales algae, toxic Leptiota, and potentially pathogenic Fusarium sequences were elevated.…”

Natural epoxyquinoids: isolation, biological activity and synthesis. An update

“…AZ0266 ( Sarcosomataceae , Pezizales ) collected from surface-sterilized decomposing leaf litter of Douglas fir ( Pseudotsuga menziesii ). 40 It was shown that sphaeropsidone reduced Candida albicans growth at concentrations above 50 μg mL −1 , but no MIC values were detected at these concentrations. The authors noted that sphaeropsidone was less active in the antifungal assay than its 1,4-dione analogue.…”

“…AZ0266 ( Sarcosomataceae , Pezizales ). 40 Strobiloscypha sp. AZ0266 was isolated from surface-sterilized decomposing leaf litter of Douglas fir ( Pseudotsuga menziesii ), an evergreen coniferous tree of southeastern Arizona.…”