Down-regulation of biofilm formation genes expression on some gram-negative bacteria by Fumaria officinalis extract

The rapid rise of antibiotic-resistant Gram-negative pathogens underscores the critical need for alternative therapeutic approaches. Biofilm formation contributes significantly to pathogen resistance and persistence. This study aimed to investigate the antibacterial and anti-biofilm activity of Fumaria officinalis (FO) extract prepared via a green ionic liquid-based extraction method, evaluating its effect on type 1 fimbriae (fimH) and outer membrane protein L (oprL) gene expression. A heat-assisted extraction method is designed and presented in the research with the objective of obtaining valuable biochemical from natural FO using the green solvent 1-butyl-3methylimidazolium chloride (BMIMCl). Quantitative spectrophotometric assays showed high concentrations of secondary metabolites including total phenols (38.84 ± 1.71 mg GAE/g), total flavonoids (36.80 ± 4.51 mg QE/g), and total terpenoids (36.52 ± 7.3 mg OAE/g). Non-volatile bioactive markers, including fumaric, caffeic, and ferulic acids, alongside flavonoids and twenty-five volatile bioactive compounds were identified via HPLC and Gas chromatography-mass spectrometry (GC-MS) analysis. Biofilm inhibition was quantified via the microtiter plate method and antibacterial activity was evaluated by agar well diffusion against biofilm-producing isolates; minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays were also performed. The effect of FO extract on the expression of the fimH and OprL genes was evaluated using the quantitative real-time polymerase chain reaction (qRT-PCR) technique. Out of 14 isolates, only three were found to be strong biofilm producers, while 4 isolates were shown to be moderate biofilm producers. The extract exhibited higher inhibitory activity against moderate biofilm-producing isolates, with MIC values 265 and 512 μg/mL. qRT-PCR demonstrated down-regulation of fimH and OprL expression in treated isolates. FO extract obtained via a sustainable green process showed antibacterial and anti-biofilm properties, partly via suppression of fimH and OprL genes expression; therefore, this study records the first green and sustainable method for FO plant biochemical compound extraction. Additionally, this work shows the inhibitory effect of FO on the two fundamental genes responsible for biofilm formation and bacterial colonization, aiming to balance the ecosystem and human well-being.