The Antibacterial Efficacy of Annona muricata (Linn) Leaves against Some Enteric Bacteria

Abstract

Aims: This research was carried out to evaluate the susceptibility patterns of some enteric bacteria to aqueous, ethanol and methanol extracts of Annona muricata leaf. Study Design: Experimental design. Place and Duration of Study: Department of Microbiology, Federal University of Technology, Akure, Ondo State, Nigeria. Between January, 2019 and May, 2019. Methodology: Extraction of bioactive components of leaves was done by maceration and phytochemical screening was carried out on the leaf extracts to determine the bioactive components present. The bacteria isolates were subjected to antibiotic sensitivity test using standard methods while the  antibacterial  activity  of  the  plant  extracts on human enteric bacteria was  determined  using  agar well dilution method. A. muricata bark extracts were purified using column chromatography method. The minimum inhibitory and minimum bactericidal concentrations (MIC/MBC) of the extracts was performed using tube dilution technique. Results: The phytochemical screening of leaf extracts showed presence of saponins, tannins, flavonoids, terpenoid and glycosides. Antibacterial activities of the leaf extracts revealed that aqueous, ethanol and methanol extracts had highest zone of inhibition of 22.00±0.58 mm, 24.67±0.33 mm and 24.00±0.58 mm respectively on Salmonella typhi. The minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) for ethanol extract ranged between 25-100 mg/ml and 50-200 mg/ml respectively while methanol extract ranged between 25-50mg/ml and 50-100 mg/ml respectively. Ciprofloxacin (CPX) was significantly (P≤0.5) the most active of all the antibiotics used against the test organisms (both clinical and typed isolates). Conclusion: This research revealed that A. muricata leaf extracts possesses antibacterial activity against human enteric bacteria isolates used in this study. The commercial antibiotics were observed to be effective in inhibiting the test organisms. The purified extracts of A. muricata leaf showed higher inhibitory effect compared to crude extracts which can serve as ingredient for the production of novel antibacterial agents for the treatment of infections caused by enteric bacteria.