Anti-Pseudomonal Activity, Antibiotic Resistance Modulation Potential, and Effect of Dichloromethane/Methanol Extract of Imperata cylindrica (Gramineae) on the Antioxidant System of Multidrug-Resistant Pseudomonas aeruginosa

Objectives Infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa are a significant public health concern. Imperata cylindrica is a dietary plant used in traditional medicine to treat many health conditions, including microbial infections. This study aimed to evaluate the anti-pseudomonal activity, antibiotic resistance modulation potential, and the effect of dichloromethane/methanol extract of I . cylindrica rhizomes on the antioxidant system of MDR P. aeruginosa . Methods The microdilution method was used to assess the anti-pseudomonal and antibiotic resistance modulation activities of the extract. The effect of the extract on catalase activity and lipid peroxidation was evaluated by measuring the height of the foam and spectrophotometric quantification of malondialdehyde, respectively. Results The tested extract displayed variable antibacterial activity, with minimum inhibitory concentrations (MICs) ranging from 32 to 2048 µg/mL. Higher anti-pseudomonal activity was observed against P. aeruginosa D130 (MIC = 32 µg/mL) and K290 (MIC = 64 µg/mL). At its sub-inhibitory concentration (MIC/8), I. cylindrica extract enhanced the activity of the tested antibiotics, mainly aminoglycosides (streptomycin, amikacin, and gentamycin), by 2 to 258-fold. The extract also affected the antioxidant system of P. aeruginosa D130, by inhibiting catalase activity, as confirmed by lipid peroxidation. Conclusion These findings indicate that the dichloromethane/methanol extract of Imperata cylindrica rhizomes can serve as a potential candidate for the discovery of new antibiotics or antibiotic-resistant modulators to efficiently treat infections involving MDR Pseudomonas aeruginosa .