Evaluation of antimicrobial and antibiofilm activities of peptide Impatiens balsamina-M1 and Zinc oxide nanoparticles against Helicobacter pylori

Abstract

Helicobacter pylori is a common human pathogen associated with chronic gastritis, peptic ulcers, and gastric cancer. The bacterium’s ability to form biofilms and acquire antibiotic resistance, especially against clarithromycin and metronidazole, has considerably reduced the efficacy of conventional treatment. These difficulties highlight the urgent need for new antimicrobial strategies that can disrupt biofilms and combat antibiotic resistance. Antimicrobial peptides and nanoparticles have emerged as promising options in this context. The antibacterial and antibiofilm properties of Impatiens balsamina-M1 (Ib-M1), green-synthesised Zinc Oxide nanoparticles (ZnO NPs), and their combination against H. pylori were assessed in this study, representing the assessment of their effects on biofilm formation, virulence gene expression, and host cell invasion. MIC (minimum inhibitory concentration) values confirmed stronger antibacterial activity of ZnO NPs (16–32 µg/mL) than Ib-M1 (500–1000 µg/mL). For H. pylori strain BY-1, the combination had an additive effect, while in other strains, it was indifferent. SEM demonstrated significant biofilm disruption, and biofilm assays showed lower MBEC (minimum biofilm eradication concentration) values with the combination. qRT-PCR revealed downregulation of cagA, vacA, ureA, hspR, and spoT, especially when treatments were combined. Flow cytometry showed that bacterial invasion into AGS gastric adenocarcinoma cells dropped from 21.9 (control) to 3.6 with the combination. All three treatments exhibited acceptable cytotoxicity, with the combination showing significantly less toxic effects on AGS cells. Together, these findings suggest that these antimicrobial agents provide a promising, environmentally friendly approach to combat antibiotic-resistant H. pylori, efficiently reducing host cell invasion, virulence gene expression, growth, and biofilm formation while maintaining low cytotoxicity. © The Author(s) 2025.