Comparative Evaluation of Selected Medicinal Plant Extracts against Multidrug Resistant Pseudomonas fluorescens: Evidence for Phytotherapeutic Potential in Kalahandi District, Odisha, India

Abstract

Background: The rapid emergence of multidrug-resistant (MDR) bacteria has become a serious global health concern. This has increased the need to explore alternative antimicrobial agents, particularly from medicinal plants known for their rich phytochemical composition. Methods: In the present study, ten medicinal plant species were collected from different locations of Kalahandi, Odisha. Ethanolic extracts were prepared using a standard solvent extraction method. Phytochemical screening was carried out to identify major secondary metabolites. The antibacterial activity of the extracts against MDR Pseudomonas fluorescens was evaluated using the well diffusion method at different concentrations (200, 300, 400, and 500 µg/ml). Minimum inhibitory concentration (MIC) was also determined in µg/ml for the most effective extracts. Results: Phytochemical analysis revealed the presence of alkaloids, flavonoids, tannins, terpenes, glycosides, and phenolics in most of the plant extracts. Nine out of ten plant species showed antibacterial activity against MDR P. fluorescens. Eucalyptus globulus exhibited the highest activity with zones of inhibition ranging from 1.2 to 1.6 cm, followed by Boswellia serrata (0.4–1.3 cm). Paederia foetida showed minimal activity and was effective only at the highest concentration. A clear dose-dependent increase in antibacterial activity was observed. Some plant extracts showed activity comparable to the standard antibiotic (azithromycin). Conclusion: The study reveals strong antibacterial activity of selected medicinal plants against multidrug-resistant Pseudomonas fluorescens. Eucalyptus globulus and Boswellia serrata showed activity comparable to azithromycin. Their dose-dependent effects and rich phytochemical content indicate  potential as sustainable, natural sources of novel antimicrobial agents to combat increasing antimicrobial resistance.