European Journal of Biomedical and Pharmaceutical Sciences

ANTIBACTERIAL ACTIVITY OF THE 70% HYDRO-ETHANOLIC EXTRACT OF *TERMINALIA MACROPTERA* (COMBRETACEAE) BARK AGAINST RESISTANT CLINICAL STRAINS OF *ESCHERICHIA COLI* FROM THE INSTITUT PASTEUR OF CÔTE D’IVOIRE, AND ANTIOXIDANT POTENTIAL

Traore Youssouf Zanga*, Ouattara Mohamed Baguy, Yao N’guessan Alain Roland,
Kouadio Guesssend Nathalie, Ouattara Abou

ABSTRACT

Background: This study is part of the ongoing effort to combat antibiotic resistance and diseases associated with oxidative stress. The aim of this work is to determine the antibacterial activity and antioxidant capacity of the hydroethanolic extract of *Terminalia macroptera* against clinical strains of *Escherichia coli*. Methods: The hydroethanolic extract was prepared using the technique described by Zihiri (2003). Tube-based staining techniques were used to identify phytochemical constituents, while the method of Blois (1958) involving the dissolution of the DPPH radical in absolute ethanol to achieve a concentration of 0.3 mg/mL was used to determine the antioxidant capacity of the 70% hydroethanolic extract. Results: The hydroethanolic extract yielded an acceptable 11.75 mg/mL. Several phytochemicals were identified, including polyphenols, saponins, tannins, flavonoids, steroids, and terpenoids. Inhibition zone diameters ranged from 19 to 25 mm, indicating good extract activity, while an MBC/MIC ratio of less than 2 demonstrated the extract's bactericidal effect against the clinical *Escherichia coli* strains tested. Antioxidant activity was assessed via DPPH radical inhibition, showing 80.19% inhibition for the extract compared to 71.53% for the reference compound, vitamin C. The concentration required for 50% inhibition (IC50) confirmed the extract's antioxidant potency, with an IC50 of 0.0022 mg/mL lower than that of vitamin C (0.0035 mg/mL). Conclusion: This study demonstrates that the 70% hydroethanolic extract possesses antibacterial properties against clinical strains of *Escherichia coli* and strong antioxidant activity for combating oxidative stress-related diseases.

Keywords: Phytochemical screening, 70% hydro-ethanolic extract, *Terminalia macroptera* bark, clinical strains, *Escherichia coli*