Coumarins, dihydroisocoumarins, a dibenzo-α-pyrone, a meroterpenoid, and a merodrimane from Talaromyces amestolkiae

Chemical investigation of an organic extract of a fungus isolated from submerged wood collected from fresh water (strain G173), identified as a Talaromyces amestolkiae (Eurotiales; Trichocomaceae), led to the isolation of three coumarins, three dihydroisocoumarins, a dibenzo-alpha-pyrone, a meroterpenoid, and a merodrimane. Three of the isolated compounds, namely 7-chloropestalasin A (3), 4-hydroxyaspergillumarin (6), and ent-thailandolide B (9) were new. The structures were elucidated using a combination of spectroscopic and spectrometric techniques. The absolute configurations of 2, 3, 5, and 6 were established via a modified Mosher's ester method, whereas for 9 a combination of TDDFT ECD and ORD calculations were employed. Compounds 1-9 were evaluated for antimicrobial activity against a group of bacteria and fungi. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The chemical investigation of a fungus isolated from submerged wood in fresh water led to the discovery of several new compounds, including coumarins and dihydroisocoumarins. The structures were elucidated using spectroscopic techniques, and the antimicrobial activity of the compounds was evaluated against a group of bacteria and fungi.