Pyrazofurin

Pyrazofurin (Pyrazomycin) is a natural product found in "Streptomyces candidus", which is a nucleoside analogue related to ribavirin. It has antibiotic, antiviral and anti-cancer properties but was not successful in human clinical trials due to severe side effects. Nevertheless, it continues to be the subject of ongoing research as a potential drug of last resort, or a template for improved synthetic derivatives.