Frenolicin B
Frenolicin B is an antibiotic and antitumor agent with the molecular formula C18H16O6 which is produced by the bacterium Streptomyces roseofulvus. Frenolicin B is a selective inhibitor of glutaredoxin 3 and peroxiredoxin 1. References

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Frenolicin B
Oxygen heterocycles
Heterocyclic compounds with 4 rings