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


Chen M, Wang R, Zhao W, Yu L, Zhang C, Chang S, Li Y, Zhang T, Xing J, Gan M, Feng F, Si S.
Org Lett. 2019 Feb 20.


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. Isocoumarindole A showed significant cytotoxicity and mild antifungal activities.