BE-24566B is a polyketide fungal metabolite originally isolated fromS. violaceusniger.1It is active againstB. subtilis,B. cereus,S. aureus,M. luteus,E. faecalis, andS. thermophilus(MICs = 1.56, 1.56, 1.56, 1.56, 3.13, and 3.13 μg/ml, respectively). BE-24566B is an endothelin (ET) receptor antagonist (IC50s = 11 and 3.9 μM for ETAand ETBreceptors, respectively).2