New Quipazine Derivatives Active Against Drug-Resistant Oncogenic Helicobacter pylori Strains with Biofilm

Helicobacter pylori (H. pylori) is regarded as a significant risk factor for gastritis, peptic ulcer disease, and gastric cancer. However, the increasing resistance of H. pylori strains has resulted in low eradication rates and ineffective treatments. Herein, we report on identification of a new quipazine derivative-compound 9c (N-(3-chlorobenzyl)-2-(piperazin-1-yl)quinolin-4-amine), which displayed antibacterial properties (MIC range 2-4 µg/mL) against H. pylori CagA-positive reference strains associated with an increased risk of gastric cancer, including metronidazole-resistant ATCC 43504, clarithromycin-resistant ATCC 700684 and susceptible J99 strain, as well as clinical, multidrug-resistant isolate (3CML, resistant to clarithromycin, metronidazole and levofloxacin). Compound 9c showed bacteriostatic activity (MBC/MIC ratio > 4), demonstrated antibiofilm-forming properties and prevented auto-aggregation of microbial cells. It also displayed an additive effect in ½ MIC (2 µg/mL) when administered with clarithromycin and/or metronidazole. Compound 9c had no impact on gut microbiota reference strains of S. aureus, E. coli, E. faecalis and L. paracasei as well as no hemolytic activity against sheep erythrocytes. Finally, by reducing the viability of the SNU-1 human gastric cancer cell line (IC₅₀ = 3.28 μg/mL), compound 9c might offer important implications regarding the oncogenic characteristics of cagA+ H. pylori strains.