Verrucarin A (Muconomycin A) is a Type D macrocyclic mycotoxin. Verrucarin A (VA), a protein synthesis inhibitor, derived from the pathogen fungus Myrothecium verrucaria, inhibits growth of leukemia cell lines and activates caspases and apoptosis and inflammatory signaling in macrophages. Verrucarin A effectively increased the phosphorylation of p38 MAPK and diminished the phosphorylation of ERK/Akt. Verrucarin A caused cell cycle deregulation through the induction of p21 and p53 [1] [2].

Verrucarin A (0-0.6 μM/ml; 24-48 hours)-induces time- and dose-dependent growth inhibition in the human breast cancer cell line MCF-7 cells [1]. Verrucarin A increases the levels of reactive oxygen species (ROS), and subsequently induces mitochondrial membrane potential (Δψm) loss, leading to the increase of Bax/Bcl-2 ratio, cytochrome c release, caspase activation, PARP degradation, and apoptosis [1]. Cell Viability Assay [1] Cell Line: MCF-7 cells Concentration: 0-0.6 μM/ml Incubation Time: 24 and 48 hours Result: Growth of MCF-7 cells is significantly inhibited in a dose- and time-dependent manner, with the IC 50 s of 0.41 and 0.29 μM/ml for 24- and 48-h treatment periods, respectively.