Screening and Mechanism Study of Antibacterial Activity of Quinoline Compounds

Quinoline compounds possess a wide range of pharmacological activities. In this paper, the antibacterial activity of 59 quinoline derivatives was evaluated against three plant bacteria in vitro. Among all the derivatives, 8‐hydroxyquinoline (8HQ) demonstrated significant antibacterial activity against Rs , Aac , Xoc , Xoo , Xac , Xcm , Xcc , Psa , and Xf , with EC 50 values ranging from 5.86 to 10.32 μg/mL. Furthermore, 8HQ exhibited a potent protective effect against Ac , with an efficacy of 69.57% at 200 μg/mL, which was not significantly different from that of the positive control kasugamycin (65.22%) and was superior to that of the positive control thiosen copper (37.68%). The bactericidal mechanism of 8HQ is likely associated with the disruption of cell membranes, inhibition of motility, reduction of extracellular polysaccharides, and interference with biofilm formation. These findings indicate that 8HQ is a promising candidate for the management of bacterial diseases in plants.