Evaluation of the Antibacterial Potential of Murraya koenigii Leaf Extracts against Escherichia coli O157 in an Albino Rat Model

Abstract

This research study investigates the antibacterial potential of Murraya koenigii (commonly known as curry leaf) in albino rats experimentally infected with Escherichia coli O157, which is a pathogen known for its severe gastrointestinal and systemic complications. The study design is experimental and also comparative in nature. This study was carried out in the animal farm of Madonna University between March 2025 and May 2025 after uptraining an ethical approval from the university research committee. This study also adhered to the relevant ethical regulations and laws on the use of animals for experimental research.    Aqueous extracts of curry leaf were prepared and administered orally to infected rats at different concentrations: The extract was reconstituted with distilled water and left for 2 days to create varying concentrations: 200 mg/kg in 10ml of distilled water, and 400 mg/kg in 10ml of distilled water, for administration in different test groups to assess the dose-dependent effects. Healthy albino rats (6-8 weeks old) weighing approximately 120-200 g were obtained from an animal farm. The animals were acclimated to the laboratory environment for 14 days under controlled temperature and humidity, with a 12-hour light/dark cycle. The experimental design included: uninfected controls, infected untreated controls, and treatment groups, with infection confirmed through microbiological and biochemical techniques. The Organism (E. coli O157) used was isolated and identified at the Nucleometrix Molecular Laboratory, Yenagoa, Bayelsa State. The animals were infected orally with a constant dosage of colony-forming units of E. coli O157 through oral gavage. Rats treated with 400 mg/kg showed more favorable results, including increased survival, improved physical activity, and reduced presence of E. coli compared to the 200 mg/kg group, which exhibited only marginal improvements. The once with high dosage treatment has no statistically significant change in body weight with a p-value of 0.9. This research project observed a dose-dependent response, suggesting that the higher concentration of bioactive compounds in the 400 mg/kg extract, such as carbazole alkaloids and flavonoids, may have played a key role in mitigating bacterial impact and supporting physiological stability. Despite the encouraging results, the variability in outcomes highlights the need for further studies on dosage optimization, mechanisms of action, and long-term effects. The findings from this research project contribute to the growing body of evidence supporting the use of Murraya koenigii as a potential natural remedy for managing E. coli O157 infections, especially in situations where conventional treatments are limited or unavailable.