Phytochemical Investigation and Antimicrobial Activity of Six Plants Used in Children’s Ailments Treatment in Niger

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Résumé

Resistance phenomena of infectious agents to synthesis drugs and the high cost of these drugs led to medicinal plants as an alternative against infectious disease. The objective of this study is to characterize different classes of secondary metabolites and to test the antibacterial activity of six plants: Bauhinia rufescens Lam, Blepharis linariifolia PERS, Chrozophora brocchiana Vis, Gardenia ternifolia Schum and Thonn, Indigofera astragalina DC, Phyllanthus pentandrus Schumach &Thonn, used in traditional medicine for children treatment. The extracts are obtained by aqueous decoction with the 1/10 model (50 g of each sample in 500 ml of solvent). Phytochemical screening of these six plants was carried out by standards tests, which are reactions of colorations, precipitation and complexation. The agr medium diffusion was used for the sensitivity test of the aqueous extracts of these plants against two strains of bacteria (two isolates of Salmonella typhimurium lettuce and clinical). Phytochemical screening showed the presence of polyphenols, tannins, flavonoids, coumarins, alkaloids, sterols/triterpenes in all tested extracts. All extracts contain saponins except Phyllanthus pentandrus. For free quinones, only Phyllanthus pentandrus and Indigofera astragalina showed a negative test. Among these six plants, five (5) showed an activity on Salmonella typhimurium at 200 mg/mL. C. brocchiana and P. pentandrus showed the best activity on S. typhimurium (lettuce) with 19.5±0.70 mm and 17.5±0.70 mm, respectively. At the concentration of 50 mg/mL, only these two plants are also showed antibacterial activity on S. typhimurium (lettuce). The results obtained indicate that these plants contain some secondary metabolites, some have antimiocrobial activity and constitute a scientific database for the research in the field of phytomedicines. These results will justify the use of these plants in the treatment of some infections.

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