INVESTIGATION OF THE IN VITRO EFFICACY OF VIGNA UNGUICULATA SUBSPECIES DEKINDTIANA ETHANOLIC EXTRACT AGAINST PSEUDOMONAS AERUGINOSA

ABSTRACT Pseudomonas aeruginosa is a multidrug-resistant pathogen responsible for persistent infections, primarily due to its ability to form biofilms, exhibit high motility, and develop antibiotic resistance. This study investigates the antimicrobial potential of Vignaunguiculata extract against P. aeruginosa, evaluating its bactericidal activity (time-kill assay), biofilm viability inhibition, synergistic effects with ciprofloxacin, and flagellar motility reduction. The time-kill assay demonstrated a gradual bacteriostatic effect between 2 and 10 hours, followed by complete bacterial eradication at 12 hours, with no regrowth observed at 14–18 hours, indicating sustained bactericidal activity. The biofilm viability assay revealed a dose-dependent reduction in biofilm-forming bacteria, with the strongest inhibition occurring at 0.02 concentration, suggesting that Vignaunguiculata disrupts biofilm integrity and bacterial adhesion mechanisms. Synergy testing with ciprofloxacin showed that a 2:1 extract-to-antibiotic ratio produced the highest synergy (82%), significantly enhancing bacterial inhibition, while a 1:1 ratio exhibited weak synergy (18%), indicating that extract concentration plays a crucial role in maximizing efficacy. The flagellar motility assay demonstrated dose-dependent motility inhibition, with 50% motility reduction at 0.02 concentration, implying that Vignaunguiculata interferes with flagellar function, potentially impairing bacterial colonization and virulence. These findings suggest that Vignaunguiculata extract exerts multifaceted antimicrobial effects against P. aeruginosa, including bactericidal action, biofilm inhibition, antibiotic synergy, and motility suppression. The results support its potential as an alternative or adjunct therapeutic agent for managing drug-resistant P. aeruginosa infections. Further studies are required to identify specific bioactive compounds, explore mechanistic pathways, and evaluate clinical applications for infection control.