Emestrin is a mycotoxin originally isolated from E. striata that has antimicrobial, immunomodulatory, and cytotoxic activities.1,2,3,4,5 It is active against the fungi C. albicans and C. neoformans, as well as the bacteria E. coli, S. aureus, and methicillin-resistant S. aureus (MRSA; IC50s = 3.94, 0.6, 2.21, 4.55, and 2.21 μg/ml, respectively).2 Emestrin is a chemokine (C-C motif) receptor 2 (CCR2) antagonist (IC50 = 5.4 μM in a radioligand binding assay using isolated human monocytes).3 Emestrin (0.1 μg/ml) induces apoptosis in HL-60 cells.4 It induces heart, thymus, and liver tissue necrosis in mice when administered at doses ranging from 18 to 30 mg/kg.5 |1. Seya, H., Nakajima, S., Kawai, K.-i., et al. Structure and absolute configuration of emestrin, a new macrocyclic epidithiodioxopiperazine from Emericella striata. J. Chem. Soc. Chem. Commun. 10, 657-658 (1985).|2. Herath, H.M.T.B., Jacob, M., Wilson, A.D., et al. New secondary metabolites from bioactive extracts of the fungus Armillaria tabescens. Nat. Prod. Res. 27(17), 1562-1568 (2013).|3. Herath, K.B., Jayasuriya, H., Ondeyka, J.G., et al. Isolation and structures of novel fungal metabolites as chemokine receptor (CCR2) antagonists. J. Antibiot. (Tokyo) 58(11), 686-694 (2005).|4. Ueno, Y., Umemori, K., Niimi, E.-c., et al. Induction of apoptosis by T-2 toxin and other natural toxins in HL-60 human promyelotic leukemia cells. Nat. Toxins 3(3), 129-137 (1995).|5. Terao, K., Ito, E., Kawai, K.-i., et al. Experimental acute poisoning in mice induced by emestrin, a new mycotoxin isolated from Emericella species. Mycopathologia 112(2), 71-79 (1990).