title: Viridicatumtoxin B
text: # Viridicatumtoxin B
  
  Viridicatumtoxin B is a fungus-derived tetracycline-like antibiotic discovered in 2008. It was isolated from small amounts of penicillium fungi. A synthetic structure matching that of natural viridicatumtoxin B makes possible synthetic variants that match or surpass its antibiotic potency.
  
  Analogs lacking a hydroxyl group were even more effective than the original against Gram-positive bacteria.
  
  Concerns about solubility, biodegradation, availability and other issues must be resolved before clinical development begins.
  
  ## History
  
  The substance was first isolated from the mycelium of liquid fermentation cultures of Penicillium species FR11.
  
  ## Structure
  
  Based on mass spectrometry and nuclear magnetic resonance data, the substance was originally thought to be the 11a',12'-epoxide, but the structure was later revised.
  
  ## Effects
  
  Viridicatumtoxin B inhibited the growth of Staphylococcus aureus, including methicillin resistant S. aureus and quinolone-resistant S. aureus with a minimum inhibitory concentration of 0.5 μg/ml. That effect is similar to that of vancomycin, but 8 to 64 times greater than that of tetracycline.
  
  ## Total synthesis
  
  A complete total synthesis of viridicatumtoxin B, in racemic form, was completed in 2013 by the group of K. C. Nicolaou.
  
  