Beilstein J Org Chem 2019 16;15:2968-2981. Epub 2019 Dec 16.
Microbial Drugs, Helmholtz Centre for Infection Research GmbH (HZI), Inhoffenstraße 7, 38124 Braunschweig, Germany.
In the course of our exploration of the Thai invertebrate-pathogenic fungi for biologically active metabolites, pigmentosin A () and a new bis(naphtho-α-pyrone) derivative, pigmentosin B (), were isolated from the spider-associated fungus sp. Furthermore, a new glycosylated asperfuran , together with one new () and two known ( and ) cyclodepsipeptides, was isolated from . The pigmentosins and showed to be active against biofilm formation of DSM1104. The lack of toxicity toward the studied microorganism and cell lines of pigmentosin B (), as well as the antimicrobial effect of pigmentosin A (), made them good candidates for further development for use in combination therapy of infections involving biofilm-forming . The structure elucidation and determination of the absolute configuration were accomplished using a combination of spectroscopy, including 1D and 2D NMR, HRMS, Mosher ester analysis, and comparison of calculated/experimental ECD spectra. A chemotaxonomic investigation of the secondary metabolite profiles using analytical HPLC coupled with diode array detection and mass spectrometry (HPLC-DAD-MS) revealed that the production of pigmentosin B () was apparently specific for sp., while the glycoasperfuran was specific for .