Evaluation of Antimicrobial Potency and Phytochemical Screening of Persea americana Leaf Extracts against Selected Bacterial and Fungal Isolates of Clinical Importance

Aim: The quest for novel bioactive from natural sources informed the evaluation of the antimicrobial alongside the phytochemical composition of leaf extracts of Persea americana obtained from Akure, Ondo State, Nigeria.

Study Design: This study assessed the prospective antimicrobial efficacy of Persia americana against selected clinically relevant bacteria and fungi.

Place and Duration of Study: The study was conducted between April and September, 2015 at the Microbiology Laboratory of the Federal University of Technology, Akure, Ondo State, Nigeria.

Methodology: Clinical isolates (Bacillus cereus, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus, Shigella flexneri, Escherichia coli, Candida albicans) and typed cultures (Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 43300, Salmonella typhi ATCC 33489) were obtained from the Pathology and Clinical Laboratory of the Lagos State University Teaching Hospital, Lagos State, Nigeria while Aspergillus fumigatus, Aspergillus niger and Aspergillus flavus were obtained from the culture collection center of the Department of Microbiology, FUTA. The authenticity of the bacterial and fungal isolates were confirmed using standard procedures. Persea americana leaves were collected from a building opposite BTO hall Ilesha garage, Akure, Ondo State and identified at the Department of Crop, Soil and Pest Management, Federal University of Technology, Akure. Antimicrobial activities of the leaves extract were assessed on clinical and typed microbial cultures using standard microbiological procedures.

Results: The extracts displayed varying antimicrobial activities against all the test organisms with zones of inhibition ranging from 10.27 mm to 34.20 mm. The leaves extracts were effective against all the organisms; with the methanolic P. americana extract having the highest antibacterial activity (34.20 mm) while the acetone extract had the highest antifungal activity (12.60 mm). The phytochemical analysis revealed the presence of tannins, flavonoids, terpenoids, alkaloids and saponins.

Conclusion: This study supports the claims that P. americana leaves could be promising in the development of drugs to combat human diseases especially those of fungal and bacterial origin.