Scientific African (Mar 2024)
In vivo antibacterial activity of the methanol extract of Voacanga africana Stapf (Apocynaceae) stem bark against clinical multidrug-resistant Salmonella Typhimurium in Wistar rats
Abstract
The emergence of multidrug-resistant (MDR) Salmonella has increased the burden of its infections. Voacanga africana, used traditionally to treat some bacterial infections, has shown weak to high antibacterial activity in vitro but in vivo studies are very rare. This study investigated the efficacy of the methanol extract of V. africana stem bark against a clinical MDR S. Typhimurium strain in Wistar rats. A curative test was done with 50 to 150 mg/kg body weight of the extract administered orally for 10 days per group of 5 female rats, infected with 3 × 108 CFUs/mL of the bacterium. Daily faecal load was determined based on the number of viable Salmonella colonies in a stool culture on Salmonella Shigella agar. A prophylactic test was also carried out whereby the extract was administered for three days prior to inoculation on day 4. At the end of both tests, blood was collected by cardiac puncture and some haematological and biochemical parameters determined. In the curative test, there was a significant dose-dependent decrease in daily faecal load or number of viable Salmonella colonies in treated rats ( p < 0.05), with 100 % clearance at 75 and 100 mg/kg, giving an ED50 of 71.8 mg/kg. The prophylactic test showed an overall lower decrease in viable counts with an ED50 of 78.24 mg/kg. No mortality or significant adverse haematological and biochemical changes were recorded in both tests. This is the first report on the in vivo anti-Salmonella activity of the methanol extract of V. africana stem bark; the high activity and lack of adverse effects indicate that this plant is a potential alternative treatment for resistant Salmonella infections and or source of an efficacious antibacterial lead. The finding supports the traditional use of this plant against bacterial infections which should be further investigated in suitable models.
