asterric-acid and sulochrin

Polluxochrin (1) and dioschrin (2), two new dimers of sulochrin linked by thioether bonds, were purified from an Alternaria sp. isolate obtained from a Hawaiian soil sample. The structures of the two metabolites were established by NMR, mass spectrometry data, and X-ray analysis. Metabolite 1 was determined to be susceptible to intramolecular cyclization under aqueous conditions, resulting in the generation of 2 as well as another dimeric compound, castochrin (3). An additional nine new metabolites were also obtained, including four new pyrenochaetic acid derivatives (8-11), one new asterric acid analogue (13), and four new secalonic acid analogues (14-17). Bioassay analysis of these compounds revealed 1-3 displayed antimicrobial and weak cytotoxic activities.

Topics: Alternaria; Anti-Bacterial Agents; Benzoates; Crystallography, X-Ray; Hawaii; Humans; Molecular Conformation; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Phenyl Ethers; Soil Microbiology

Two new chlorinated diphenyl ethers (5, 6) have been isolated from the culture broth of an Aspergillus species obtained from leaf litter, together with the known benzophenone sulochrin (1), the grisandiene geodin (2), and the diphenyl ether asterric acid (3). The structure of another metabolite, methyl asterrate (4), was confirmed by single-crystal X-ray structure analysis.

Topics: Antifungal Agents; Antinematodal Agents; Aspergillus; Australia; Benzoates; Benzofurans; Chromatography; Crystallography, X-Ray; Nuclear Magnetic Resonance, Biomolecular; Oxygenases; Phenols; Phenyl Ethers