Oxepinamides L and M, two new oxepine-pyrimidinone-ketopiperazine type nonribosomal peptides from Aspergillus californicus

Abstract

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.

Graphical Abstract

Keywords:

• Aspergillus californicus
• oxepine
• nonribosomal peptides
• oxepinamide

Acknowledgments

The authors thank Dr. Kasper Enemark-Rasmussen and Associate Professor René Wugt Larsen from the Department of Chemistry at the Technical University of Denmark for acquiring NMR and IR data, respectively. Emil H. Kristiansen is acknowledged for his work on strain cultivation and chemical extraction.

Disclosure statement

The authors declare no potential conflicts of interest.

Additional information

Funding

This work was supported by the China Scholarship Council under grant number 201709110107.