Table 3.

QS inhibitor activity of selected compounds in P. aeruginosa (PAO1) reporters.

Compound	IC50 lasB-GFP	IC50 rhlA-GFP	IC50 pqsA-GFP	IC50 PAO1-GFP
Indole-3-acetic acid	Not active	Not active	>3125 μM	Not active
6-methyl salicylic acid	Not active	Not active	2809 μM	Not active
Rubrofusarin	Not active	>62,5 μM	17 μM	Not active
Citrinin	>2000 μM	Not active	1062 μM	Not active
Desmethyl Gregatin A	509 μM	Not active	130 μM	Not active
Gregatin A	228 μM	516 μM	203 μM	Not active
Gregatin D	282 μM	398 μM	294 μM	Not active
Cyclogregatin	>500 μM	Not active	>500 μM	Not active

IC₅₀ values of the different reporters were determined. Compounds were scored as “non-active” when it was not possible to plot a nonlinear regression curve because of lack of inhibitory activity. In case there was inhibitory activity, but 50% inhibition was not reached, the IC₅₀ value was estimated to be higher than the highest concentrations tested. Higher concentrations could not be tested due to excessively high DMSO concentrations or precipitation of the compound.