Antibacterial activity against multidrug-resistant Salmonella, toxicity and biochemical effects of Moringa oleifera leaf extracts in mice

Ngemenya MN, Itoe LO, Awah LA, Asongana R, Ndip RA. 2024. Antibacterial activity against multidrug-resistant Salmonella, toxicity and biochemical effects of Moringa oleifera leaf extracts in mice. Asian J Nat Prod Biochem 22: 43-50. The emergence of multidrug resistance has significantly compromised the treatment of Salmonella infections. The anti-Salmonella activity, toxicity, and biochemical effects of Moringa oleifera Lam. leaf crude extracts were studied by disc diffusion and microdilution against Multidrug-Resistant (MDR) strains. Cytotoxicity was investigated on monkey kidney epithelial cells (LLCMK2) and acute toxicity in BALB/c mice. Both hexane (MOHEX) and methanol (MOMET) extracts produced small zones of inhibition of 8mm at 1 mg and 2 mg per disc, indicating weak activity, but the minimum inhibitory concentration showed high (0.0625 mg/mL) to low activity (10 mg/mL) activity. No minimum bactericidal concentration was recorded at the concentrations tested. The 50% cytotoxic concentration (CC50) for methanol and hexane extracts were 2524 µg/mL and 5004 µg/mL, respectively, indicating a low risk of toxicity. No mortality or adverse effects were recorded in the acute toxicity test. Both extracts had no significant effects (p < 0.05) on renal function and one liver enzyme (alanine aminotransferase), but MOMET significantly increased aspartate aminotransferase (p = 0.04), suggesting possible liver toxicity. The study shows that M. oleifera leaves possess bacteriostatic activity against multidrug-resistant Salmonella and are non-toxic; hence, it is a potential alternative treatment against multidrug-resistant Salmonella. Further studies of fractions and pure natural products of the extracts should be pursued.