Elsinopirins A–D, Decalin Polyketides from the Ascomycete Elsinoё pyri

Abstract

In course of our screening for new secondary metabolites from ecological niche specialized, phytopathogenic fungi, the plant pathogen Elsinoё pyri, strain 2203C, was found to produce four novel compounds (1–4), which were named elsinopirins A–D, in addition to the known metabolite elsinochrome A (5). After isolation by preparative high-performance liquid chromatography (HPLC), their structures, including relative stereochemistry, were elucidated by 1D and 2D nuclear magnetic resonance (NMR) and mass spectrometry (MS) data. Finally, absolute stereochemistry was assigned by chemical shifts of Mosher’s esters (α-methoxy-α-trifluoromethylphenylacetic acid; MTPA) derivatives of elsinopirin B (2). The compounds were found to be devoid of significant antibacterial, antifungal, and cytotoxic activities.

A New Antioxidant Decalin Polyketide from Freshwater‐Sediment‐Derived Fungus Penicillium sp. Strain S1a1

“…Additional proof for 1 to be a true natural product is that the methylation occurred only at the more reactive carboxylic group of the two carboxylic acid moieties in the molecule and its parent compound 11‐desmethyl derivative (tanzawaic acid Z) was also a natural compound. In fact, compound 1 expands the related unique alkylated decalin polyketides, elsinopirins A–D, which were recently isolated by Stadler and co‐workers . Interestingly, compound 1 along with elsinopirins A–D demonstrate typical examples for β ‐methyl branching of polyketides which has been extensively discussed by many reviews …”

“…In fact, compound 1 expands the related unique alkylated decalin polyketides, elsinopirins A-D, which were recently isolated by Stadler and co-workers. [12] Interestingly, compound 1 along with elsinopirins A-D demonstrate typical examples for β-methyl branching of polyketides which has been extensively discussed by many reviews. [13] The isolated compound was assessed for its antiproliferative, antibacterial and in vitro antioxidant activity by the DPPH assay using quercetin as a reference compound under the same experimental conditions.…”

New Peptaibiotics and a Cyclodepsipeptide from Ijuhya vitellina: Isolation, Identification, Cytotoxic and Nematicidal Activities

“…Both the 1 H-NMR and the HSQC spectra were recorded and chemical shift values with considerable changes were noted as shown in Table S2 (Supplementary Information). Exactly the same experimental procedure was repeated to prepare the R-MTPA-methyl ester but with using the S-(+) MTPA-Cl in pyridine-d 5 [27,28].…”

Structurally diverse metabolites from the rare actinobacterium Saccharothrix xinjiangensis

“…Minimum inhibitory concentrations were determined by a serial dilution assay in 96-well plates with EBS medium for bacteria and MYC medium for fungi. 29…”