Helvolic acid

Helvolic acid is a steroidal antibiotic compound classified as a fusidane-type nortriterpenoid. It is a tetracyclic steroid acid characterized by a 29-nordammarane skeleton, which is substituted with acetoxy groups at positions C-6 and C-16, oxo groups at C-3 and C-7, and double bonds at C-1, C-17, and C-24. Its molecular formula is.

Natural occurrence

The acid is produced by various fungi, notably Aspergillus species such as Aspergillus fumigatus and Aspergillus terreus, as well as members of the genus Fusarium and Xylaria. The acid was originally isolated from Aspergillus fumigatus.
Helvolic acid was isolated from the culture broth which was separated from the fungus mycelium by filtration.