Susceptibility Patterns of Some Enteric Bacteria to Crude and Purified Bark Extracts of Annona muricata L.

Aims: This research was carried out to evaluate the susceptibility pattern of some enteric bacteria to crude and purified extracts of Annona muricata bark.

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 bark was done by maceration and phytochemical screening was carried out on the bark 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 were performed using tube dilution technique.

Results: The quantitative phytochemical screening for bark extract revealed that glycosides (7.06±0.04, 34.67±0.02 and 19.35±0.01) extracted with aqueous, ethanol and methanol respectively is the most abundant phytochemical constituents. The antibacterial activities of the bark extracts revealed that aqueous showed no inhibition to none while ethanol and methanol inhibited all the test organisms. The highest value of minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) for both ethanol and methanol bark extracts was 50 mg/ml and 100 mg/ml respectively.

Conclusion: This research revealed that A. muricata bark extracts possesses antibacterial activity against human enteric bacteria isolates used in this study. The purified extracts of A. muricata bark showed higher zones of inhibition which indicates that it can compete well with standard antibiotics and it may also serve as a substitute to the commercially available antibiotics that can be used for the treatment of infections caused by enteric bacteria.