PHYTOCHEMICAL PROPERTIES AND ANTIBACTERIAL ACTIVITIES OF METHANOLIC STEM BARK EXTRACT OF NAUCLEA LATIFOLIA ON SELECTED CLINICAL BACTERIAL ISOLATES

The increasing prevalence of antibiotic resistance has intensified the search for alternative therapeutic agents from medicinal plants. This study investigated the phytochemical composition and antibacterial activities of the methanolic stem bark extract of Nauclea latifolia against selected clinical bacterial isolates (Escherichia coli and Staphylococcus aureus). The stem bark was collected, dried, powdered, and extracted using cold maceration with methanol. Qualitative phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, saponins, steroids, and glycosides, while anthraquinones were absent. Antibacterial activity was assessed using the agar disk diffusion method at concentrations of 50 mg/ml, 100 mg/ml, and 200 mg/ml, with ciprofloxacin and dimethyl sulfoxide (DMSO) as positive and negative controls, respectively. Results showed that the extract exhibited concentration-dependent antibacterial activity, producing inhibition zones ranging from 9.20 ± 0.45 mm to 19.80 ± 0.56 mm, with S. aureus being more sensitive than E. coli. The minimum inhibitory concentration (MIC) values were 12.5 mg/ml for S. aureus and 25.0 mg/ml for E. coli, while the minimum bactericidal concentration (MBC) values were 25.0 mg/ml and 50.0 mg/ml, respectively. Although the antibacterial activity of the extract was lower compared to ciprofloxacin, the findings validate the ethnomedicinal use of N. latifolia in treating bacterial infections. The presence of bioactive compounds suggests synergistic effects contributing to its antimicrobial efficacy. This study highlights the therapeutic potential of N. latifolia as a complementary and affordable source of antibacterial agents, particularly in regions with limited access to conventional antibiotics. Further studies on bioassay-guided fractionation and toxicity evaluation are recommended to isolate active constituents and ensure safety for clinical application.