Pyoluteorin is an antibiotic that inhibits Oomycete fungi, including the plant pathogen Pythium ultimum, and suppresses plant diseases caused by this fungus. Pyoluteorin induces human triple-negative breast cancer MDA-MB-231 cells apoptosis in vitro.

Pyoluteorin is an antifungal compound composed of a bichlorinated pyrrole linked to a resorcinol moiety, were identified within a 24-kb genomic region of Pseudomonas fluorescens Pf-5[1]. Pyoluteorin has significant cytotoxicity towards MCF-7 (IC50=1.84 μM). Pyoluteorin also displays significantly selective cytotoxicity against BT474, HCC1954, MAD-MB-468, MDA-MB-231, and MCF-10A cells with IC50 values of 9.75±0.16, 0.94±0.01, 3.89±0.08, 0.97±0.01, and 57.01±0.76 μM, respectively[2]. Pyoluteorin (0.1-10 μM; for 24 hours) induces change of apoptosis-related protein expressions. Pyoluteorin-induced cell apoptosis in MDA-MB-231 is related to Bcl-2 family proteins and caspase cascade[2]. Pyoluteorin (0.1-10 μM; for 24 h) induces cell cycle arrest and apoptosis in human triple-negative breast cancer cells MDA-MB-231[2].