Phytochemical Study and Evaluation of the Antimicrobial Activity of Terminalia avicennioides (Guill and Perr) Leaf Extracts on the Bacteria Involved in Common Infections in Niger

Background and Objective: The leaves of Terminalia avicennioides are used in Western Niger against gastric disorders and skin infections.The objective of the study is to perform phytochemical screening of the leaves of Terminalia avicennioides extracts and test their antimicrobial activity with special interest in the bacteria most involved in diarrheal infections Escherichia coli, Shigella flexneri, Salmonella typhi and Staphylococcus aureus and reference.Materials and Methods: The methanol and aqueous extracts of this plant were prepared with the leaf powder.Aqueous extract was prepared by decoction and the methanolic extract was prepared by maceration.The major families of secondary metabolites were searched in the crude extracts following standard characterization methods.The extract was evaluated for the presence of alkaloids, flavonoids, tannins, saponins, steroids and glycosides.The evaluation of the antibacterial activity of the extracts was carried out using the disk diffusion method.The MICs and MBCs were used to investigate the antimicrobial activity.Results: Phytochemical research revealed the presence of phenols, tannins, flavonoids and steroids.Leaves extract showed high levels of phenolic compounds which are derivatives of gallic acid and a significant level of flavonoid and tannins: Moderate antibacterial activity against clinical strains Salmonella typhi, Staphylococcus aureus and Shigella flexneri and showed no effects on Escherichia coli.Better antimicrobial activity was observed with an ethyl acetate fraction of the methanolic extract.Conclusion: Phytochemical studies on Terminalia avicennioides's leaves revealed a variety of phenolic compounds which have many biological activities.Thus, it can explain the traditional basis for using this plant in the treatment of various diseases such as anti-inflammatory, hemostatic, cicatrizing and antidiarrheal.