Antibacterial activity of Sarcocephalus latifolius and Acacia sieberiana, and the effect of their association with antibiotics against multidrug-resistant Staphylococcus aureus

Abstract

Background: Infectious diseases continue to wreak havoc around the world causing directly or indirectly 17 million deaths per year. The present study was carried out to evaluate the in vitro antibacterial activity of the methanol extracts from the root of Sarcocephalus latifolius and from the leaves of Acacia siberiana, and their ability to potentiate the action of antibiotics against multidrug-resistant (MDR) Staphylococcus aureus. Methods: The antibacterial assays were performed using the broth microdilution method, and the extracts were screened for phytochemicals using standard qualitative methods. The effect of Sarcocephalus latifolius root extract on the functioning of H+/ATPases proton pumps of ATCC25923 Staphylococcus aureus was determined using a standard qualitative method. Results: The extracts of Sarcocephalus latifolius and Acacia siberiana had minimum inhibitory concentrations (MIC) ranging from 16 to 1024 µg/mL and 32 to 1024 µg/mL, respectively, with action spectra of 93.75% and 87.5% against the 16 strains of Staphylococcus aureus tested. The S. latifolius root extract contained alkaloids, phenols, and terpenoids as the main classes of secondary metabolites. In contrast, the A. siberiana leaf extract contained phenols and terpenoids as the major classes of secondary metabolites. The S. latifolius extract enhanced the activity of penicillin against 100% of the isolates tested. On the other hand, the A. siberiana extract enhanced the activity of Cefixime against 85.71% of the isolates tested with a 128-fold increase in activity. Conclusion: The results obtained in this study provide significant data that could potentially support the use of Sarcocephalus latifolius and Acacia siberiana in combating bacterial infections caused by multidrug-resistant Gram-positive Staphylococcus aureus.