Atropisomeric dihydroanthracenones as inhibitors of multiresistant Staphylococcus aureus

J Med Chem. 2013 Apr 25;56(8):3257-72. doi: 10.1021/jm301816a. Epub 2013 Apr 16.

Abstract

Two bisdihydroanthracenone atropodiastereomeric pairs, including homodimeric flavomannin A (1) and the previously unreported flavomannin B (2), two new unsymmetrical dimers (3 and 4), and two new mixed dihydroanthracenone/anthraquinone dimers (5 and 6) were isolated from Talaromyces wortmannii , an endophyte of Aloe vera . The structures of 2-6 were elucidated by extensive NMR and mass spectrometric analyses. The axial chirality of the biaryls was determined using TDDFT ECD and VCD calculations, the combination of which however did not allow the assignment of the central chirality elements of 1. The compounds exhibited antibacterial activity against Staphylococcus aureus , including (multi)drug-resistant clinical isolates. Reporter gene analyses indicated induction of the SOS response for some of the derivatives, suggesting interference with DNA structure or metabolism. Fluorescence microscopy demonstrated defective segregation of the bacterial chromosome and DNA degradation. Notably, the compounds showed no cytotoxic activity, encouraging their further evaluation as potential starting points for antibacterial drug development.

Publication types

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

MeSH terms

  • Aloe / microbiology
  • Animals
  • Anthracenes / chemistry
  • Anthracenes / isolation & purification*
  • Anthracenes / pharmacology
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / isolation & purification*
  • Anti-Bacterial Agents / pharmacology
  • BALB 3T3 Cells
  • Cell Line, Tumor
  • DNA, Bacterial / drug effects
  • Drug Resistance, Multiple, Bacterial / drug effects*
  • Endophytes / chemistry
  • Eurotiales / chemistry
  • Humans
  • Mice
  • Microbial Sensitivity Tests
  • Nuclear Magnetic Resonance, Biomolecular
  • SOS Response, Genetics / drug effects
  • Staphylococcus aureus / drug effects*
  • Stereoisomerism

Substances

  • Anthracenes
  • Anti-Bacterial Agents
  • DNA, Bacterial