Table 2.
Natural compounds as quorum sensing inhibitors.
| Natural compound(s) | Source | QS activity | Ref. |
|---|---|---|---|
| Furanone/ 2(5H)-Furanone/ | Macroalga (Delisea pulchra) | Mimics AHL signal by occupying the binding site on putative regulatory protein which results in the disruption of QS-mediated gene regulation. Inhibit biofilm formation in Aer. hydrophila | 109, 17 |
| Repress LuxR protein dependent expression of P(luxI)-gfp(ASV) reporter fusion. Inhibit virulence factor in E. coli XL-1. | 110 | ||
| (5Z)-4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone. | Macroalga (Delisea pulchra) | Disrupts QS-regulated bioluminescence in V. harveyi by interacting with Hfq protein. Inhibit swarming motility and biofilm formation in E. coli | 111, 112 |
| Ajoene (1-Allyldisulfanyl-3-(prop-2-ene-1-sulfinyl)-propene) |
Garlic extract (Allium sativum) | Blocks the QS-regulated productions of rhamnolipid resulting in phagocytosis of biofilm. Targets Gac/RSM part of QS and lowers the expression of regulatory RNAs in P. aeruginosa PAO1 | 113, 114 |
| Iberin (1-Isothiocyanato-3-(methylsulfinyl)propane) |
Horseradish extract (Armoracia rusticana) | Inhibit expression of QS-regulated lasB-gfp and rhlA-gfp genes responsible for virulence factor in P. aeruginosa | 115 |
| Sulforaphane (1-Isothiocyanato-4-(methylsulfinyl)butane) |
Boroccoli | Reduce the expression of lasI-luxCDABE reporter in P. aeruginosa | 116 |
| Erucin (4-methylthiobutyl isothiocyanate) | Boroccoli | Reduce the expression of lasI-luxCDABE reporter in P. aeruginosa | 116 |
| Naringin (4'5-diOH-Flavone-7-rhgluc) |
Citrus extract | Decrease the QS mediated biofilm formation and swimming motility in Y. enterocolitica | 18 |
| Naringenin (4',5,7-Trihydroxyflavanone) |
Malagasy bark extract (Combretum albiflorum) | Reduces production of pyocyanin and elastase in P. aeruginosa PAO1. Also inhibit 3-oxo-C12-HSL and C4-HSL synthesis driven by lasl and rhll genes | 117, 118 |
| Taxifolin/ Distylin (dihydroquercetin) |
Malagasy plant extract (Combretum albiflorum) | Reduces production of pyocyanin and elastase in P. aeruginosa PAO1 | 117 |
| Morin (2',3,4',5,7-Pentahydroxyflavone) | Grapefruit (Artocarpus heterophyllus) | Inhibit LasR and RhlR dependent protease, elastase and hemolysin in P. aeruginosa PAO1 | 119, 120 |
| Patulin/ Clavacin (4-Hydroxy-4H-furo[3,2-c]pyran-2(6H)-one) |
Penicillium sp. | Targets the RhlR and LasR proteins. Down-regulates QS genes for biofilm formation and virulence in P. aeruginosa | 121 |
| Penicillic acid (3-Methoxy-5-methyl-4-oxo-2,5-hexadienoic acid) |
Penicillium sp. | Down-regulates QS genes for biofilm formation in P. aeruginosa | 121 |
| Vanillin (4-Hydroxy-3-methoxybenzaldehyde) |
Vanilla beans extract (Vanilla planifolia Andrews) | Interfere with AHL receptors. Inhibit C4-HSL, C6-HSL, C8-HSL, 3-oxo-C8-HSL. Inhibit biofilm formation in Aer. hydrophila | 122, 123, 16 |
| Agrocinopine B ( [(3S,4R,5R)-3,4,5,6-tetrahydroxy-2-oxohexyl] [(2R,3S,4S)-3,4,5-trihydroxy-1-oxopentan-2-yl] hydrogen phosphate) | Crown gall cells | Control conjugation of pTiC58 by regulating exprssion of the arc operon in A. tumefaciens | 124 |
| L-canavanine (L-α-Amino-γ-(guanidinooxy)-n-butyric acid) |
Seed exudates (Medicao sativa) | Inhibit the expression of QS-regulated phenotype exopolysaccharide II production in Si. meliloti | 125 |
| Gamma-aminobutyric acid (GABA) ( 4-Aminobutanoic acid) |
Plants (Arabidopsis sp.) | Induce the expression of attKLM operon to stimulate inactivate 3-oxo-C8-HSL by A. tumefaciens lactonase AttM | 126, 127 |
| Rosmarinic acid (R-O-(3,4-Dihydroxycinnamoyl)-3-(3,4- dihydroxyphenyl) lactic acid) | Sweet basil (Ocimum basilicum) | Inhibit protease, elastase, hemolysin production, biofilm formation and virulence factor in P. aeruginosa | 119, 108, 128 |
| Salycilic acid (2-Methyl-5-tert-butylsalicylic acid) | Plant phenolic secondary metabolite | Inhibit the expression of vir regulon in A. tumefaciens. Also stimulates AHL-lactonase expression which degrades AHLs. | 129 |
| Chlorogenic acid (3-Caffeoylquinic acid) | Plant extract (Moringa oleifera) | Inhibit QS-regulated violacein production in C. violaceum 12472 | 130 |
| Allin (2-Amino-3-[prop-2-ene-1-sulfinyl]-propionic acid) |
Garlic extract (Allium sativum) | Inhibit QS-regulated gene expression by interacting with receptors in P. aeruginosa and make biofilm sensitive to antibiotics. | 113, 131 |
| Ursolic acid (3beta-Hydroxyurs-12-en-28-oic acid) | Plant extract (Sambucus chinesis) | Inhibit biofilm formation by suppressing cystenine synthesis in E. coli | 132, 133 |
| Ellagic acid (Benzoaric acid) | Fruit extract of Terminalia chebula Retz. | Down-regulate the expression of virulence gene in P. aeruginosa PAO1. Reduces biofilm formation and swarming motility in B. cepacia | 134, 135 |
| α-Hydroxybutyric acid (2-hydroxy-butanoic acid) | Arabidopsis exudates | Induce the expression of attKLM-lacZ fusion in A. tumefaciens | 136 |
| Epigallocatechin gallate (Epigallocatechol) | Green tea (Camellia sinensis L.) | This compound has gallic acid moiety and specifically block AHL-mediated biofilm formation in Sta. aureus and B. cepacia. Inhibit transfer of conjugative R plasmid in E. coli | 135, 137-139 |
| Pyrogallol (1,2,3-Trihydroxybenzene) |
Plant extract (Punica granatum) | Inhibit AI-2 mediated bioluminescence in V. harveyi | 140, 141 |
| Cinnamon oil/ Cynnamaldheyde ( trans-Cinnamaldehyde) | Cinnamomum zeylanicum | Interfere with AI-2 based QS and decreases the DNA-binding ability of LuxR protein to reduce virulence in V. spp. Reduces LuxR-mediated transcription from the PluxI promoter which influences biofilm formation in P. aeruginosa | 142, 143 |
| Furocoumarin/ Psoralen (7H-Furo[3,2-g][1]benzopyran-7-one) |
Grapefruit juice and extract (Psoralea corylifolia L.) | The structural resemblance of furan moiety results in QS-mediated inhibition of biofilm formation in E. coli. Inhibit QS-mediated swarming motility in P. aerugionsa PAO1 | 144, 145 |
| Urolithin (3,8-Dihydroxy-benzo[c]chromen-6-one) |
Ellagitannin-rich extract from Pomegranate | Inhibit C6-HSL and 3-oxo-C6-HSL associated biofilm formation in Y. enterocolitica. Inhibit QS-mediated swarming motility in E. coli and P. aerugionsa PAO1 | 146, 147 |
| Curcumin (E,E)-1,7-bis(4-Hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione | From Curcuma longa | Down-regulates virulence factors and biofilm initiation genes in P. aerugionsa PAO1 and inhibit its phenotype expression. | 19 |
| Attenuate QS-dependent EPS production, swarming motility and biofilm formation in uropathogenic E. coli, P. aerugionsa, Pr. mirabilis and S. marcescens. | 148 | ||
| α-D-galactopyranosyl-(1→2)-glycerol (floridoside) (N), Betonicine (O), and Isethionic acid |
Red alga (Ahnfeltiopsis flabelliformis) | Inhibit C8-HSL mediated QS in A. tumefaciens NTL4 | 149 |
| Musaceae | Musaceae extract (Musa paradiciaca) | Inhibit QS-mediated elastase production and biofilm formation in P. aerugionsa PAO1 | 150 |
| Garlic | Garlic extract | Interferes with expression of QS-controlled virulence genes in P. aeruginosa | 121 |
| Piper betle | Piper betle extract | Inhibit QS-mediated biofilm formation in P. aeruginosa | 151 |
| Cuminum cyminum | Cuminum cyminum extract | Reduce LuxR dependent biofilm formation and swarming motility of P. aerugionsa | 152 |