TABLE 2.

Studies on controlling biofilm by targeting QS signaling receptors.

Source	QS-inhibiting agents	Chemical structure	Target bacteria	Effects	References
Lactobacillus	3-Phenyllactic acid (PLA)		P. aeruginosa	Bound to QS receptors RhlR and PqsR with high affinity, thus inhibited the expression of virulence factors such as protease, pyocyanin and rhamnolipids that are involved in the biofilm formation	Chatterjee et al., 2017
Synthesis	Sitagliptin		P. aeruginosa	Interacted with LasR receptors, and significantly inhibited the biofilm formation	Abbas et al., 2020
Plant	Naringenin		P. aeruginosa	Competed with OdDHL by directly binding the QS regulator LasR, inhibited the production of the QS-regulated virulence factors, pyocyanin and elastase	Hernando-Amado et al., 2020
Plant	Fructose-furoic acid		Uropathogenic E. coli	Competed with the SdiA native ligand C8HSL to down regulate its target specific expression and biofilm phenotypic characters	Vinothkannan et al., 2018
Synthesis	Furanones		P. aeruginosa	Competed with the native autoinducers to bind to the AHL receptors, and significantly decreased virulence factor production and biofilm formation	Proctor et al., 2020
Synthesis	Meta-bromo-thiolactone		P. aeruginosa	Inhibited receptors LasR and RhlR, prevented virulence factor expression and biofilm formation	O’Loughlin et al., 2013
Synthesis	N-phenyl-4-(3-phenylthioureido) benzenesulfonamide		E. coli(EAEC) O104:H4	allosterically modified AI-3 receptor QseC, impeded virulence expression and decreased biofilm formation	Curtis et al., 2014