A new cyclopeptide metabolite of marine gut fungus from Ligia oceanica

Abstract

A new cyclopeptide, together with three known amino acid derivatives, was isolated from marine-derived fungus Aspergillus flavipes, which was found in the gut of isopod Ligia oceanica. The novel peptide contains four amino acid units, proline, 5-methoxyanthranilic acid, isoleucine and 3-aminoacrylic acid. Its structure was determined on the basis of NMR, HR-MS and MSⁿ spectral data analysis. The two unusual amino acid residues, 5-methoxyanthranilic acid and 3-aminoacrylic acid, were first found in natural product. The known compound N-benzoyl-phenylalanine methyl ester was first found as fungal metabolite. This is the first report of natural products isolated from marine gut fungi.

Keywords::

• gut fungus
• Aspergillus flavipes
• cyclopeptide
• 5-methoxyanthranilic acid
• 3-aminoacrylic acid

Acknowledgements

The research was supported by the National Natural Science Foundation of China (NSFC No. 21102128), Qianjiang Excellence Project of Zhejiang Province (2010R10053) and Union Opening Foundation of CAS' Key Laboratory of Marine-resources Sustainable Utilization, Chinese Academy of Sciences (LMB121004).