In-vitro antibacterial activity of crude extracts of Annona senegalensis against selected bacteria associated with urinary tract infections

Abstract

The treatment of urinary tract infections (UTIs) has become challenging due to antimicrobial resistance exhibited by the causative organisms. Medicinal plants are alternatives to conventional drugs and complement treatment for diverse infections owing to the growing antimicrobial resistance to synthetic drugs. The study assessed the antibacterial activity of aqueous, ethyl acetate, and methanol extracts of leaves, bark, and roots of A. senegalensis against selected bacteria associated with urinary tract infections (UTIs). The extracts of A. senegalensis were obtained by the soxhlet extraction method. Qualitative phytochemical screening of the extracts was carried out using standard procedures. The bacteria tested were Klebsiella pneumoniae and Pseudomonas aeruginosa isolated from urine samples of UTI patients. Antimicrobial susceptibility testing was carried out using the agar well diffusion method, while minimum inhibitory concentration (MIC) was determined by broth dilution method using two-fold serial dilutions. The qualitative phytochemical analysis showed the presence of phenols, tannins, terpenoids, flavonoids, steroids, saponins, and cardiac glycosides. Zones of inhibition of extracts at 400 mg/mL ranged between 16.33±0.58 – 24.67±0.58 mm (leaf extracts), 14.00±1.00 – 21.33 ±0.58 mm (bark extracts) and 14.67±0.58 – 21.00±1.00 mm (root extracts). The highest zone of inhibition (24.67±0.58 mm) observed was against Pseudomonas aeruginosa with aqueous leaf extract, while the least inhibition (14.00±1.00 mm) was with ethyl acetate bark extract, also against Pseudomonas aeruginosa. MIC values ranged from 25 to 100 mg/mL, while MBC values ranged from 50 to 200 mg/mL against the test isolates. A. senegalensis demonstrated great antibacterial potential and can be recommended for treating UTIs.