New diketopiperazine dimers and 4-hydroxyphenylacetates from an endolichenic fungus Aspergillus sp.

Two novel diketopiperazine dimers (1 and 2) and two new 4-hydroxyphenylacetates (5 and 6), along with two previously known diketopiperazine dimers were isolated from the culture of the endolichenic fungus Aspergillus sp. CPCC 400810. Their structures were determined through comprehensive spectroscopic analysis, including high-resolution electrospray ionization mass spectrometry (HRESIMS) and 1D and 2D nuclear magnetic resonance (NMR) data.

Cytotoxic metabolites from the endophytic fungus 7951.

The following compounds were isolated from acetate extracts of 7951 solid cultures: demethylchaetocochin C (1) and chaetoperazine A (3), two new epipolythiodioxopiperazine (ETP) alkaloids, a novel pyridine benzamide, 4-formyl--(3'-hydroxypyridin-2'-yl) benzamide (6), and three known ETP derivatives (2, 4, and 5). The structures of these compounds were determined using extensive spectroscopic data analysis. Compounds 1-3, and 6, inhibited the growth of MCF-7, MDA-MB-231, H460 and HCT-8 cells with an IC of 4.

Isocoumarindole A, a Chlorinated Isocoumarin and Indole Alkaloid Hybrid Metabolite from an Endolichenic Fungus Aspergillus sp.

Isocoumarindole A (1), a novel polyketide synthetase-nonribosomal peptide synthetase (PKS-NRPS) hybrid metabolite, was isolated from the endolichenic fungus Aspergillus sp. CPCC 400810. The structure of isocoumarindole A (1) was featured by an unprecedented skeleton containing chlorinated isocoumarin and indole diketopiperazine alkaloid moieties linked by a carbon-carbon bond, which was determined by a combination of spectroscopic analyses, Marfey's method, and calculations of NMR chemical shifts, ECD spectra, and optical rotation values.