Supplementary file 1_Characterization of the antibacterial and biofilm inhibitory activities of Arctium lappa L. (greater burdock) against representative members of the ESKAPE group.docx

MIC and MBC values ranged from 64 to 512 and 128–512 μg/mL, respectively, while MBIC₅₀ values ranged from 64 to 256 μg/mL. Time-kill assays demonstrated bactericidal activity, with Gram-negative strains reaching a ≥3-log10 reduction within 6 h and Gram-positive strains showing slower killing kinetics. LIVE/DEAD staining, scanning electron microscopy, and atomic force microscopy showed changes consistent with compromised membrane integrity, while H2DCFDA assays showed increased intracellular ROS in S. aureus (181% ± 11%) and P. aeruginosa (214% ± 13%) relative to untreated controls.

A modified disk diffusion assay also showed increased inhibition zones for selected extract–antibiotic combinations. The individual metabolites responsible for these effects were not chemically identified, which limits direct linkage between predicted biosynthetic pathways and observed activity. Overall, the findings demonstrate antibacterial and biofilm-inhibitory activity of A. lappa extract and support further bioassay-guided fractionation and metabolomic characterization.</p>