Antibacterial Potential of Annona muricata (Linn.) Leaf Extract: A Promising Natural Source for Novel Antibacterial Therapies
Authors: Wilkie Eunice Damilola , Michael Peter Oluwadamilola , Oluduro Anthonia Olufunke , Alao Jude Oluwapelumi 
Published: July 2023

Aims: Bacterial infections pose a significant public health challenge, necessitating the search for new antimicrobial agents. This study investigated the antibacterial potential of Annona muricata (Linn.) leaf ethyl acetate extract against some bacterial pathogens.

Study Design:  An experimental design was adopted for this study.

Place and Duration of Study: Fresh leaves of Annona muricata (Linn.) were collected from Modakeke, Osun State, South-West, Nigeria. Proper identification and authentication of the leaves were carried out at the herbarium unit of the Department of Botany, Obafemi Awolowo University (OAU), Ile-Ife, Osun State, Nigeria.

Methodology: The plant material was extracted using ethyl acetate, and concentration-dependent assays determined antibacterial activity, including minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The phytochemical analysis identified bioactive compounds.

Results: The extract concentrations of 35.00 mg/ml, 17.50 mg/ml, 8.75 mg/ml, and 4.38 mg/ml demonstrated significant antibacterial activity against a total of ten bacterial strains out of the twenty-one (47.6%) tested. These strains include Klebsiella pneumoniae, Proteus vulgaris, Staphylococcus mariliensis, Salinicoccus roseus, Enterobacter asburiae, Streptococcus canis, Streptococcus pyogenes, Streptococcus equi, Limonorella grimontii, Proteus hauseri, Citrobacter werkmanii, Staphylococcus rosterii, Versinia enteroculitica, Macrococcus bruensis, Precoccus suis, Limorella richardii, Staphylococcus aureus, Macroccocus lavnae, Salmonella enterica, Streptococcus salviohxodontae, and Klebsiella ozanae. The range of obtained inhibition zone values varied from 70 mg/ml to 4.38 mg/ml. The minimum inhibitory concentration (MIC) values varied between 4.48 mg/ml and 35.00 mg/ml, while the minimum bactericidal concentration (MBC) values ranged from 2.19 mg/ml to 17.5 mg/ml. Susceptibility to the extract increased with higher concentrations. Comparative analysis with ampicillin indicated superior inhibitory                      properties. Phytochemical analysis of the extract revealed the presence of some phytochemical constituents.

Conclusion: The ethyl acetate extract obtained from Annona muricata (Linn.) leaf demonstrated significant antibacterial activity against tested bacterial isolates. The extract exhibited concentration-dependent inhibitory effects, indicating the presence of bioactive compounds with antibacterial properties. These findings highlight the potential of Annona muricata (Linn.) as a source for developing natural antibacterial agents. Further research is needed to isolate and identify the specific active compounds, understand their mechanisms of action, and assess the extract's therapeutic potential and safety profile. The study emphasizes the importance of exploring natural plant extracts for their antibacterial properties and opens avenues for future applications in medicine and pharmaceuticals.