Antimicrobial Mechanisms of <scp><i>Hibiscus sabdariffa</i></scp> Extracts and Hibiscus Acid Against <scp><i>Campylobacter jejuni</i></scp>: Membrane Disruption, Biofilm Modulation, and Antibiotic Resistance Implications

ABSTRACT The objective was to evaluate the antimicrobial effects and possible mechanisms of action of extracts of Hibiscus sabdariffa calyxes and hibiscus acid (AH) on Campylobacter jejuni . The antimicrobial effect of extracts of H. sabdariffa calyxes (obtained with water, acetone, methanol, and ethanol) was evaluated alone and in a mixture with antibiotics using the paper disk technique. Possible damage to the membrane through permeability modification, leakage of genetic material and proteins, modification of zeta potential ( ζ ), electrophoretic mobility, pore formation, and the effect on biofilm formation was also investigated. The study found that extracts from H. sabdariffa calyxes, particularly the acetone extract (AE) and AH, effectively inhibited C. jejuni by damaging its membrane, causing leakage of genetic material and proteins, and altering zeta potential ( ζ ) and electrophoretic mobility. Both AE and AH also disrupted biofilm formation and induced membrane porosity. However, no synergistic effect was observed when combined with antibiotics. The findings suggest that these extracts could be potential alternatives to antibiotics for combating antibiotic‐resistant C. jejuni .