Phytochemicals and antibacterial efficacy of Annona muricata (soursop) stem bark and leaf extracts against some clinical bacterial isolates

Abstract

The threat of drug-resistant pathogens necessitates exploring plant-derived bioactive compounds to develop potent antibacterial solutions. This study determined the phytochemicals and antibacterial activities of Annona muricata (soursop) stem bark and leaf  extracts against some clinical bacterial isolates. The phytochemicals and antibacterial activity of leaf and stem bark extracts of Annona  muricata were analyzed following standard methods. Invitro susceptibility of bacteria isolates to the plant extracts was evaluated using  the agar well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the plant  extracts were also determined using the broth dilution method. The result of quantitative and qualitative phytochemical composition of  the leaf and stem bark extracts of Annona muricata showed the presence of alkaloids, flavonoids, saponins, phenols, tannins, terpenoids,  glycosides, and anthraquinones. The quantitative phytochemical composition of the leave extract revealed the presence of total alkaloids  content (577.07±2.19), total flavonoids content (22.37±1.40), total tannin content (0.69±0.12), total saponin content (3.90±0.06), and total phenolic content (3.51±0.26) for leaf aqueous extract. The findings of this study revealed that Annona muricata (soursop) stem bark and  leaf extracts were active against clinical Salmonella, Escherichia coli, and Staphylococcus aureus isolates. The diameter of zones of  inhibition observed was concentration dependent for both the stem bark and leaf extracts. Diameter of zones of inhibition ranged  between 0.07 ± 0.033 to 8.07 ± 0.067 mm in leaf extract and 0.07 ± 0.033 to 3.39 ± 0.140 mm lowered in stem bark extracts. In conclusion,  all Annona muricata extracts showed potential in preventing Salmonella, E. coli, and S. aureus infections, with the ethanolic extract  demonstrating the strongest activity, highlighting the potential of plant secondary metabolites in controlling these infections.