Vol. 6, Issue 1, Part A (2024)

Bacterial infection by Salmonella remains a real public health threat causing each year, more than 1.2 million deaths worldwide. The causal pathogen is Salmonella spp, whose treatment by antibiotic therapy is usually compromised due to the emergence of multi-resistant strains, supply chain problems and the high cost of drugs in less developed countries where the infection is usually endemic. Faced with these difficulties, the local populations with limited resources resort to medicinal plants and essential oils, whose anarchic use poses effectiveness and safety challenges. With the aid of microdilution, the antibacterial activity of Azadirachta indica seed oil was evaluated on three Salmonella strains. Subsequently, an acute toxicity study of the extract was performed on Wistar rats by dosing the test groups with 2 ml/100kg of body weight, according to the slightly modified Organisation for Economic Co-operation and Development (OECD) guideline 420. The extracted oil gave a yield of 18.6%. Two of the three identified bacterial strains were susceptible with diameters of 17 mm for Salmonella typhi and 18.5mm for Salmonella paratyphi A. Their minimum inhibitory and bactericidal concentration were 37.5mg/ml and 150 mg/ml respectively with a CMB/CMI ratio equals to 4 which demonstrated that, oil from the Azadirachta indica seeds used had anti-salmonella bacteriostatic properties. Acute toxicity analyses showed that the lethal dose 50 (LD 50) of this oil was greater than 2ml/100g. We concluded that Azadirachta indica seed oil contained important bioactive metabolites with promising anti-Salmonella bacteriostatic activity on two bacterial strains. It was toxicologically safe at the dose of 2 ml/100g of body weight.