Five Tetramic Acid Derivatives Isolated from the Iranian Fungus Colpomaquercinum CCTU A372.

Gian Primahana,Frank Surup,Marc Stadler,Rémy Bertrand Teponno,Mahdi Arzanlou,Abolfazl Narmani

doi:10.3390/biom11060783

Abstract

Submerged mycelial cultures of the ascomycete Colpoma quercinum CCTU A372 were found to produce five previously undescribed tetramic acids, for which we propose the trivial names colposetins A–C (1–3) and colpomenoic acids A and B (4 and 5), along with the known compounds penicillide (6) and monodictyphenone (7). The planar structures of 1–5 were determined by high-resolution electrospray ionization mass spectrometry (HR-ESIMS) and extensive 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. Their absolute configurations were determined by the combination of electronic circular dischroism (ECD) analysis, J-based configurational analysis, and a rotating-frame Overhauser effect spectroscopy (ROESY) experiment. Colposetin B displayed weak antimicrobial activity against Bacillus subtilis and Mucor hiemalis (MIC 67 µg/mL).

Highlights

Fungi are a valuable group of organisms with promising biotechnological and industrial applications
In the last two decades, the discovery rate of novel fungal secondary metabolites has accelerated significantly [2]. They were isolated from fungi from underexplored genera, from interesting ecologies, that interact with other fungi, plants, or animals, and that exist in geographic areas that so far have not been exhaustively explored [3]
NH4 OAc + 0.04 mL/L CH3 COOH); flowrate 0.3 mL/min using gradient elution system starting from 10% to 100% B in 30 min, hold for 10 min at 100% B and followed by postrun for equilibrating to the initial condition for 10 min; column temperature was set to 40 ◦ C; 96-well microtiter plates were used for fractionation; and the eluates were collected every

Summary

Introduction

Fungi are a valuable group of organisms with promising biotechnological and industrial applications. One of them is a producer of secondary metabolites with various biological activities ranging from medicines to agrochemicals [1]. In the last two decades, the discovery rate of novel fungal secondary metabolites has accelerated significantly [2]. They were isolated from fungi from underexplored genera, from interesting ecologies, that interact with other fungi, plants, or animals, and that exist in geographic areas that so far have not been exhaustively explored [3]. In the last several years, numerous secondary metabolites have been isolated from underexplored genera or habitats. A novel isoindolinone and indanone, chaetosisoindolinone and chaetosindanone were isolated from a new species of plant associated fungus Chaetosphaeronema achilleae collected in Iran [4], udagawanones A and

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Conclusion