Antibacterial and antifungal screening of natural products sourced from Australian fungi and characterisation of pestalactams D–F Academic Article uri icon

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abstract

  • Eighteen natural products sourced from Australian micro- or macro-fungi were screened for antibacterial and antifungal activity. This focused library was comprised of caprolactams, polyamines, quinones, and polyketides, with additional large-scale isolation studies undertaken in order to resupply previously identified compounds. Chemical investigations of the re-fermented culture from the endophytic fungus Pestalotiopsis sp. yielded three caprolactam analogues, pestalactams D-F, along with larger quantities of the known metabolite pestalactam A, which was methylated using diazomethane to yield 4-O-methylpestalactam A. The chemical structures of the previously undescribed fungal metabolites were determined by analysis of 1D/2D NMR and MS data. The structure of 4-O-methylpestalactam A was confirmed following single crystal X-ray diffraction analysis. The antibacterial and antifungal activity of all compounds was assessed, which identified three compounds, (1S,3R)-austrocortirubin, (1S,3S)-austrocortirubin, and 1-deoxyaustrocortirubin with mild activity (100 μM) against Gram-positive isolates and one compound, 2-hydroxy-6-methyl-8-methoxy-9-oxo-9H-xanthene-1-carboxylic acid, with activity against Cryptococcus neoformans and Cryptococcus gattii at 50 μM.

authors

  • Beattie, Karen
  • Ellwood, Nicola
  • Kumar, Rohitesh
  • Yang, Xinzhou
  • Healy, Peter C
  • Choomuenwai, Vanida
  • Quinn, Ronald J
  • Elliott, Alysha G
  • Huang, Johnny X
  • Chitty, Jessica L
  • Fraser, James A
  • Cooper, Matthew A
  • Davis, Rohan A

publication date

  • April 2016