Three new azaphilone alkaloids containing glutamine residues, namely N-glutarylchaetoviridins A-C (1-3), together with two related compounds (4 and 5) were isolated from the extract of Chaetomium globosum HDN151398, a fungus isolated from a deep-sea sediment sample collected in South China Sea. Their structures were elucidated on the basis of extensive 1D and 2D NMR as well as HRESIMS spectroscopic data and chemical analysis. N-glutarylchaetoviridins A-C (1-3) represent the first class of chaetoviridins characterized by embedded glutamate residues. Amino acids incubation experiments produced five azaphilone laden different amino acids residues (6-10) which indicated that this method can enhanced the structural diversity of this strain by culturing with amino acids. Cytotoxicity of the isolated compounds were evaluated against a panel of human cancer cell lines.
Keywords: Chaetomium globosum; azaphilone alkaloids; cytotoxicity; deep-sea-derived fungus.