PqsR-IN-1 (Compound 18) is a potent inhibitor of PqsR, a transcriptional regulator in the quorum sensing mechanism of Pseudomonas aeruginosa, that effectively reduces pyocyanin production and exhibits minimal cytotoxicity [1].

PqsR-IN-1 (Compound 18) effectively inhibits the pqs system in Pseudomonas aeruginosa, with IC50 values of 313 ± 156.2 nM and 342 ± 39.4 nM against PAO1-L and PA14 strains, respectively [1]. At triple the IC50 value, it reduces pyocyanin production to 23% in the PAO1-L strain compared to a 0.1% DMSO control [1]. Moreover, PqsR-IN-1 exhibits minimal toxicity towards A549 lung epithelial cells, showing no significant adverse effects at concentrations ranging from 0-100 μM after 16 hours of exposure [1].