In Vivo Antibacterial and Biochemical Effects of Moringa oleifera Leaf Extract in a Rat Model of Multidrug-Resistant Salmonella Typhimurium.

The burden of Salmonella infections remains high largely due to emergence of antibiotic-resistant strains. Moringa oleifera used in traditional medicine to treat bacterial infection has shown considerable antibacterial activity in several in vitro studies but has not been extensively investigated in vivo. The aim of this study was to assess the antibacterial activity of this plant in a rat model of a multidrug-resistant (MDR) Salmonella strain as a potential alternative treatment. A MDR strain of Salmonella Typhimurium was detected using antibiotic susceptibility. Then a methanol extract of M. oleifera leaves was prepared, and the minimum inhibitory concentration (MIC) against the MDR strain was determined by microdilution. Rats were infected with the MDR S. Typhimurium, and the extract (125-500 mg/kg of body weight) was administered orally for 10 days. The fecal load of the bacterial colonies was determined by the plate count method. On day 11, the rats were sacrificed, blood was collected, and biochemical effects on liver and renal functions were assessed in serum. The extract showed high activity against the MDR S. Typhimurium in vitro with a MIC of 2 mg/mL. There was a significant decrease in fecal colonies at all treatment doses compared to the negative control group (p < 0.01), indicating high efficacy of the extract. Optimal in vivo activity of 100% inhibition was observed at 500 mg/kg on day 10. There were no significant changes in biochemical parameters (p < 0.05), and no mortality was recorded indicating lack of adverse effects. The high in vivo anti-Salmonella activity of the methanol extract of M. oleifera coupled with no adverse effects supports its use in traditional medicine. Hence, it is a potential alternative treatment for resistant Salmonella infections. M. oleifera should be further investigated in vitro and in vivo against other resistant bacteria.