New Glutamine-Containing Azaphilone Alkaloids from Deep-Sea-Derived Fungus Chaetomium globosum HDN151398

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.