Purpose: In this experiment, we used two different types of phytochemicals (Zanthoxylum armatum and Hibiscus sabdariffa) in three different concentrations (5, 10 and 15%) to inhibit the growth of Escherichia coli 0157:H7, Listeria monocytogenes, Salmonella enterica, and Staphylococcus aureus by using disc diffusion method.
Methods: Bacteria stains were cultured in Tryptic Soy Broth and incubated overnight at 37 °C. The turbidity of each suspension was then adjusted to match that of a 0.5 McFarland standard: 1.5 X 108 CFU/ml. The suspension was then plated onto Muller-Hinton Agar (MHA) then allowed to dry at room temperature, then were place onto MHA that contain the bacteria. The discs were infused with 50 µl of two phytochemicals of the three concentrations (5, 10, and 15 %), then plates were allowed to dry for 45 minutes and were incubated overnight at 37 °C.
Results: Results of this experiment showed that 10 and 15% concentrations of both phytochemicals (Zanthoxylum armatum and Hibiscus sabdariffa) were more effective to reduce the growth of E. coli, L. monocytogenes and S. aureus compared to control. Results also indicated that 10% concentration of Hibiscus sabdariffa was more effective than Zanthoxylum armatum. Naturally, 15% concentration of both phytochemicals effectively inhibited the growth of above mentioned bacteria.
Significance: Natural extracts like Zanthoxylum armatum and Hibiscus sabdariffa can provide protection as promising antibacterial agents.