INTRODUCTION: The rising prevalence of antibiotic-resistant Pseudomonas aeruginosa underscores the urgent need for new antimicrobial approaches. This pathogen forms biofilms and produces quorum-sensing (QS)-regulated factors that aid its survival and resistance. This study investigates the antimicrobial, antibiofilm, and QS gene expression effects of Cichorium intybus root extracts on clinical P. aeruginosa isolates. METHODS: Ethanolic and aqueous extracts of C. intybus were prepared and analyzed for phenolic, flavonoid, flavonol, and anthocyanin content. Antioxidant activity was assessed using the DPPH assay. Antibacterial activity was evaluated using well diffusion, MIC, and MBIC assays. Biofilm formation was quantified using crystal violet staining, and QS gene expression (lasR, lasI, lasB) was analyzed by qRT-PCR. RESULTS: The aqueous extract had higher phenolic content, whereas the ethanolic extract contained more flavonoids and flavonols (p<0.05). Only strain PA3 was sensitive to the extracts. The ethanolic extract produced larger inhibition zones (15 mm vs. 13 mm, p<0.05), had a MIC of 0.048 g/ml, and significantly inhibited biofilm formation at 0.024 g/ml (p<0.05). qRT-PCR results indicated decreases in lasI, lasR, and lasB gene expression by 23%, 39.9%, and 35.7%, respectively. DISCUSSION: These results suggest that C. intybus root extracts, particularly ethanolic extracts, can suppress P. aeruginosa growth and biofilm formation while modulating QS-regulated virulence factors. This suggests a promising alternative to conventional antibiotics. CONCLUSION: The ethanolic extract of C. intybus root exhibits notable antimicrobial, antibiofilm, and antivirulence activity, highlighting its promise as a treatment option.
Zolfaghari et al. (Thu,) studied this question.