Pyrazofurin
Pyrazofurin (Pyrazomycin) is a natural product present in Streptomyces
candidus, a Ribavirin derived nucleoside analog. It has antibiotic,
antiviral, and anti-cancer properties but due to extreme side effects,
it was not effective in human clinical trials. Nevertheless, it
continues to be the focus of ongoing research as a possible 2019-nCoV
drug, or as a blueprint for improved synthetic derivatives [16-22].