A chemical investigation of Aspergillus californicus IBT 16748 led to the isolation of two new oxepine-pyrimidinone-ketopiperazine type nonribosomal peptides oxepinamides L (1) and M (2). Their structures were characterised by spectroscopic analysis including HRESIMS, 1D and 2D NMR. The absolute structure of 1 was assigned by ECD calculation. The antibacterial and cytotoxic properties of 1 were evaluated.
Keywords: Aspergillus californicus; nonribosomal peptides; oxepinamide; oxepine.