Abstract
Biofilms pose significant challenges in clinical and environmental settings due to their role in antibiotic resistance. Iron and zingerone have emerged as potential biofilm modulators, yet their combined impact on AHL-mediated biofilm formation remains underexplored. This study aimed to investigate the synergistic effects of iron and zingerone on AHL-dependent biofilm formation in Agrobacterium tumefaciens. Minimum inhibitory concentration (MIC) assays determined appropriate concentrations of zingerone (500 μg/mL). Biofilm assays, conducted in 96-well plates, revealed no significant differences in biofilm formation among the treatments iron, zingerone, and iron and zingerone together. However, a LacZ reporter assay showed significant reductions in AHL-mediated quorum sensing with zingerone treatment (p < 0.05). Iron alone did not significantly affect quorum sensing in this assay, nor did its presence enhance the inhibitory effect of zingerone. These findings suggest that iron has a negligible impact on both biofilm formation and quorum sensing in A. tumefaciens. Interestingly, while zingerone inhibits AHL-mediated quorum sensing, it does not seem to affect overall biofilm formation in A. tumefaciens. Further research is needed to elucidate the relationship between these results and optimize biofilm inhibition strategies.