6-Paradol exhibits antimicrobial, anti-quorum sensing and anti-virulence capacities on gram-negative bacteria: In vitro and in vivo studies

Grains of paradise, which are native to Africa, contain 6-paradol, an antibacterial compound found in plants of the Zingiberaceae family. In this study, the antimicrobial and anti-virulence properties of 6-paradol were evaluated against significant Gram-negative bacteria. The assessment encompassed the impact of 6-paradol on the bacterial cell membrane, efflux mechanisms, bacterial motility, biofilm formation, and extracellular enzyme production. The findings demonstrated promising anti-quorum sensing activity of 6-paradol. Moreover, the outcomes unveiled that the antimicrobial activity of 6-paradol is primarily stems from its substantial influence on the bacterial cell membrane and efflux mechanisms. Furthermore, 6-paradol exhibited potential anti-virulence activities by effectively reducing the generation of biofilm and virulent enzymes, impeding bacterial motility, and inhibiting in vivo bacterial pathogenesis. These anti-virulence effects were attributed to the compound's interference with quorum sensing systems and the downregulation of genes associated with these systems. Additionally, when combined with antibiotics, 6-paradol demonstrated synergistic effects. In conclusion, 6-paradol possesses noteworthy anti-virulence activities and can be employed as an auxiliary alongside antibiotics for treating aggressive Gram-negative infections. This highlights its potential as a valuable addition to therapeutic strategies.