Phytochemical screening and evaluation of the antimicrobial properties of the hydroethanolic extracts of Ziziphus spina-christi L., Cassia obovata L., and Euphorbia hirta L. on the pathogenic bacteria of N'Djamena-Chad urinary tract infections

Background: The emergence of bacteria resistant to certain classes of antibiotics poses a global public health problem, particularly in developing countries. Traditional medicine plays a crucial role in the treatment of infectious diseases, particularly urinary tract infections, in Chad. It is in this context that this research was conducted in Chad to encourage the search for new antibacterial molecules derived from three medicinal plants used in traditional Chadian medicine. Objectives: This research aims to study the groups of chemical compounds present in the hydroethanolic extracts of Z. spina-christ L., C. obovata L., and E. hirta L., and to evaluate their in vitro antibacterial activity against uropathogenic bacterial strains acquired and isolated at the bacteriology laboratory of the National University Hospital Center in N'Djamena, Chad. Methods: The plant samples were macerated in a hydroethanolic solvent (ethanol/water, 70/30). A phytochemical screening of the hydroethanolic extracts of Z. spina-christ L., C. obovata L., and E. hirta L. was performed to identify alkaloids, saponins, flavonoids, and tannins as secondary metabolites. Antibacterial activity was evaluated using the liquid microdilution method combined with the agar plate technique to determine the MIC and MBC. Results: Phytochemical analysis revealed the presence of secondary metabolites such as alkaloids, flavonoids, saponins, and tannins in all hydroethanolic extracts of Z. spina-christi L., C. obovata L., and E. hirta L. All hydroethanolic extracts completely inhibited the growth of Gram-positive cocci and Gram-negative bacilli at a concentration of 50 mg/mL. The hydroethanolic extracts of Z. spin-christi L. and C. obovata L. exhibited a bacteriostatic effect against E. coli (MIC = 12.5 mg/mL), whereas E. hirta exhibited a bactericidal effect. The hydroethanolic extracts of the three plants exhibited a bactericidal effect against K. pneumoniae, with significant inhibition (P < 0.05). Conclusion: In summary, these three medicinal plants possess significant in vitro antibacterial activity against uropathogenic bacterial strains. The results of this study scientifically confirm their use in traditional medicine, which should be the subject of further studies aimed at identifying the toxic effects of these plants. The isolation of active compounds and an in vivo evaluation are necessary prior to any therapeutic application.