Inhibition of <i>Salmonella</i> Typhimurium biofilm and polysaccharide production via eugenol-glucosyltransferase interactions

This study hypothesizes that eugenol, due to its structural properties, can inhibit glucosyltransferase activity, thereby reducing polysaccharide synthesis in <i>Salmonella</i> Typhimurium biofilms. It was found that eugenol exhibited minimum inhibitory and bactericidal concentrations of 0.6 mg mL⁻¹ and 0.8 mg mL⁻¹, respectively, against planktonic <i>S.</i> Typhimurium growth. It also demonstrated minimum biofilm eradication and inhibition concentrations of 1.8 mg mL⁻¹ and 0.7 mg mL⁻¹, respectively. At 0.3 mg mL⁻¹, eugenol reduced biofilm formation and affected polysaccharide production. Moreover, eugenol reduced glucosyltransferase activity. Computational analysis indicated strong interactions between eugenol and the enzyme’s active site residues with affinity energy −8.5 kcal mol⁻¹. Real-time PCR revealed a significant increase in <i>bcsA</i> gene expression in the presence of eugenol. These findings suggest that eugenol’s ability to inhibit glucosyltransferase activity effectively reduces biofilm formation and polysaccharide content.