Infusion or Decoction Extracts of Helianthus annuus Leaves: Potential Inhibitors for QS system and Biofilm Formation in Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa is one of the drug-resistant opportunistic pathogens with the ability to form biofilm and to produce a number of virulence factors via Quorum Sensing (QS) regulation. Most researchers have focused on QS inhibition to overcome the drug resistance problem. QS inhibitor molecules are investigated from natural resources. In the present study, anti-QS activities of ethyl acetate extracts of decoction and infusion samples from Helianthus annuus leaves were tested on biosensor strains of P. aeruginosa (lasB-gfp, rhlA-gfp and pqsA-gfp), as well as anti-biofilm activities on PAO1 wild type. H. annuus leaf samples were firstly infused or decocted and then extracted with ethyl acetate. The efficacies of infusion or decoction extracts were examined at the concentrations of 240, 120, and 60 μg/ml in 96-well microplates and evaluated in Citation 3 multimode microplate reader (Biotek). The inhibition rates of decoction extracts were recorded as 70.61% for las, 44.09% for rhl and 83.77% for pqs system at 240 μg/ml. The biofilm inhibition percentages of the extracts were determined to be 50.82% (±1.36). Moreover, inhibition rates for infusion extracts were detected as 62.08% for las, 45.15% for rhl and 77.79% for pqs, and 53.88% (±3.94) for biofilm formation. In conclusion, the potential efficacies of the extracts of decocted or infused H.annuus leaves were demonstrated on QS system and biofilm formation of P. aeruginosa. However, there is a need for more detailed investigations and determination of the active substances that have QSI and anti-biofilm effect.