Chicory fraction and 8-deoxylactucin inhibit growth and virulence traits of resistant Pseudomonas aeruginosa

Abstract

Chicory (Cichorium intybus L.) is a plant widely cultivated for the inulin production. The plant is underutilized regarding sesquiterpene lactones that might express potent pharmacological activities, and are currently discharged as a byproduct. Our study aimed to investigate both fraction and lactone antimicrobial potential and ability to reduce viability of P. aeruginosa cells in biofilms (MTT assay), as well as their ability to produce exopolysaccharides (Congo red binding assay), extracellular DNA and form biofilms on urinary catheters. Chicory fraction and 8-deoxylactucin exhibited promising antibacterial activity towards antibiotic resistant strain of P. aeruginosa (MIC 0.5 and 0.06 mg/mL, respectively). Chicory fraction has reduced drastically (>50% inhibition with MIC of agent) viability of P. aeruginosa cells in biofilm, while the activity of 8-deoxylactucin was less profound (<30% inhibition). Likewise, application of chicory fraction in MIC concentration has significantly limited the ability of P. aeruginosa cells to produce exopolysaccharides (>40% inhibition) and eDNA (>60% inhibition), known biofilm resistance factors. Biofilms formed on urinary catheters are challenging threat in hospital environments. Though, ability of both chicory fraction and 8-deoxylactucin to reduce ability of P. aeruginosa to attach to catheter surface should be further explored as promising novel antibacterial treatment since application of both agents at their MIC concentrations has induced more than 50% inhibition.