Table 1.

Herbal Extracts as Quorum Sensing Inhibitors and Their Effects on the P. aeruginosa QS System

Quorum Sensing Inhibitor Compounds	Quorum Sensing Efficacy	Ref.
Coumarin	Production of biofilm and pathogenic factors production	[76]
Pistacia atlantica crude extract	Production of biofilm and pyocyanin secretion	[11]
Curcumin	Motility phenotypes and production of biofilm	[131]
Ginseng	Production of LasA and LasB and synthesis of the AHL molecules	[141]
Baicalin	Production of biofilm and pathogenic factors (protease, elastase, pyocyanin, rhamnolipid, motilities and exotoxin A)	[142]
Flavonoids (naturally-produced plant Metabolites)	LasR and RhlR receptors	[143]
Ajoene, a Sulfur-Rich Molecule from Garlic	Pathogenic factors production	[144]
Berberine	Production of biofilm, secretion of protease, pyoverdin, pyocyanin and the expressions of lasI, lasR, rhlI, rhlR genes	[133]
Trans-cinnamaldehyde	Secretion of protease, elastase, pyocyanin and production of biofilm and the expressions of lasI, lasR, rhlI, rhlR genes	[145]
Salicylic acid	Secretion of protease, elastase, pyocyanin and production of biofilm and the expressions of lasI, lasR, rhlI, rhlR genes	[145]
Phillyrin	Pyocyanin, rhamnolipid, elastase, swimming and twitching motility and biofilm formation	[146]
Trans-anethole	Swarming motility, secretion of protease, elastase, pyocyanin and the expressions of lasB gene	[147]
Cinnamic acid	Secretion of pyocyanin, proteases, elastase and production biofilm	[148]
Hordenine	Swarming motility, secretion of pyocyanin, elastase, rhamnolipid, production of biofilm and the expressions of lasI, lasR, rhlI, rhlR genes	[149]
Eugenol from clove extract	Pathogenic factors and production of biofilm	[150]
Ocimum sanctum	Secretion of pyocyanin, protease, elastase and production of biofilm	[151]
Musa paradisiaca	Pyocyanin, protease, elastase and biofilm formation	[151]
Caffeine	Motility phenotypes	[151]
Methanolic extract of Phyllanthus amarus	Motility phenotypes, pyocyanin secretion	[152]
Zingerone	Motility phenotypes, production of biofilm and pathogenic factors production	[153]
Combretum albiflorum	Elastase secretion and production of biofilm	[154]
Allium sativum (garlic) extract	Production of biofilm, elastase secretion	[155,156]
FL fraction of Psidium guajava L	Virulence factors production and production of biofilm	[157]
Clove oil	Protease, chitinase and pyocyanin secretion, swimming motility and production of biofilm	[158]
The methanol extract of fenugreek	Protease, LasB elastase, pyocyanin and chitinase production, swarming motility and production of biofilm	[159]
The dichloromethane extract of Cordiagilletii	Pyocyanin secretion, the expression of genes lasB, rhlA, lasI, lasR, rhlI, and rhlR genes and production of biofilm	[160]
Manilkara zapota	Pyocyanin, protease and elastase secretion and production of biofilm	[151]
Diarylheptanoids from the barks of Alnus viridis and Alnus glutinosa	Pyocyanin secretion, twitching motility and production of biofilm	[161]
Gingerol	Exoprotease, rhamnolipid and pyocyanin secretion and biofilm formation	[162]
Diterpene phytol	Pyocyanin secretion, twitching motility and production of biofilm	[163]