The Collaborative International Dictionary of English v.0.48:

Cerulenin \Ce`ru*len"in\, n. [isolated from Cephalosporium
   caerulens.] (Chem.)
   an antifungal antibiotic, C12H17NO3. It inhibits the growth
   of yeasts by interfering with the synthesis of sterols and
   fatty acids.
   [PJC]