Antibacterial activity of Sapium ellipticum, Securidaca longepedunculata, and Allophylus africanus against drug-resistant Pseudomonas aeruginosa isolates

Pseudomonas aeruginosa poses a major clinical challenge due to its high levels of antibiotic resistance. This study evaluated the antibacterial activity of three medicinal plant extracts Allophylus africanus (leaves), Securidaca longepedunculata (root bark), and Sapium ellipticum (stem bark), against 30 drug-resistant P. aeruginosa isolates. Antibacterial screening was conducted using the agar well diffusion method, followed by determination of minimum inhibitory concentrations (MICs) via a 96-well microtiter plate assay. All three plant extracts demonstrated inhibitory activity against three resistant P. aeruginosa strains (gentamicin-resistant strains F4 and GR4RAU-AI, and ceftazidime-resistant strain 19-10), with inhibition zones of varying diameters. MIC values showed strain-specific susceptibility, ranging from 195.3–3125 µg/mL for A. africanus, to 390.63–6250 µg/mL for S. longepedunculata, and 390.63–3125 µg/mL for S. ellipticum. Despite variability in effectiveness across strains, the plant extracts exhibited promising antibacterial potential against multidrug-resistant P. aeruginosa. Further studies are warranted to elucidate their active components, modes of action, and potential as alternative therapies for resistant infections.