Isolation of pyrrolocins A-C: cis- and trans-decalin tetramic acid antibiotics from an endophytic fungal-derived pathway

J Nat Prod. 2014 Nov 26;77(11):2537-44. doi: 10.1021/np500617u. Epub 2014 Oct 29.

Abstract

Three new decalin-type tetramic acid analogues, pyrrolocins A (1), B (2), and C (3), were defined as products of a metabolic pathway from a fern endophyte, NRRL 50135, from Papua New Guinea. NRRL 50135 initially produced 1 but ceased its production before chemical or biological evaluation could be completed. Upon transfer of the biosynthetic pathway to a model host, 1-3 were produced. All three compounds are structurally related to equisetin-type compounds, with 1 and 3 having a trans-decalin ring system, while 2 has a cis-fused decalin. All were active against Mycobacterium tuberculosis, with the trans-decalin analogues 1 and 3 exhibiting lower MICs than the cis-decalin analogue 2. Here we report the isolation, structure elucidation, and antimycobacterial activities of 1-3 from the recombinant expression as well as the isolation of 1 from the wild-type fungus NRRL 50135.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / isolation & purification*
  • Anti-Bacterial Agents / pharmacology*
  • Bacillus subtilis / drug effects
  • Endophytes / chemistry*
  • Ferns / microbiology*
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Molecular Structure
  • Mycobacterium tuberculosis / drug effects
  • Naphthalenes / chemistry
  • Nuclear Magnetic Resonance, Biomolecular
  • Papua New Guinea
  • Pyrrolidinones / chemistry
  • Pyrrolidinones / isolation & purification*
  • Pyrrolidinones / pharmacology*
  • Staphylococcus aureus / drug effects
  • Stereoisomerism
  • Streptococcus pneumoniae / drug effects
  • Tetrahydronaphthalenes / chemistry

Substances

  • Anti-Bacterial Agents
  • Naphthalenes
  • Pyrrolidinones
  • Tetrahydronaphthalenes
  • pyrrolocin A
  • pyrrolocin B
  • pyrrolocin C
  • tetramic acid
  • equisetin
  • decalin