Physico-chemical composition and evaluation of the cytotoxicity and antibacterial activity of extracts of Euphorbia hirta, Citrus aurantifolia and Heterotis rotundifolia on enteropathogenic strains

[Speaker] Phénix E. C. ASSOGBA:1
[Co-author] Dougnon T. Victorien:1,2, Roko Gautier:1, Honoré BANKOLE S.:1, Baba-Moussa Lamine:3
1:Unité de recherche en microbiologie apliquée et pharmacologie des substances naturelles, 1, Benin, 2:Dougnon victorien, Benin, 3:Baba-moussa lamine, Benin

Infectious diseases such as diarrhea are generally very dangerous in human pathology especially when they are spread by ingestion of water or food contaminated with stool or by direct contact with infected stool. Bacterial resistance to antibiotics is increasing and becoming a major public health problem. This study aims to evaluate the antibacterial, antioxidant and cytotoxic properties of the aqueous and ethanolic extracts of the plants of Euphorbia hirta, Citrus aurantifolia and Heterotis rotundifolia; used in Benin in the traditional treatment of many diseases including infectious diseases and diarrhea.
To do this, the phytochemical screening was carried out by differential reactions of precipitation and staining. The antibacterial activity was carried out through sensitivity tests by the diffusion method in agar medium coupled to the joint determination of Minimal Inhibitory Concentrations and Bactericidal by the method of dilution in liquid and solid media. The antioxidant activity was studied by the methods of reduction of the radical DPPH. Toxicity of all extracts was evaluated on Artemia salina shrimp larvae.
Thus, the results of the phytochemical screening reveal that the aqueous extracts have a high polyphenol content compared to the ethanolic extracts with the exception of the ethanolic extract of Heterotis rotundifolia which has a higher polyphenol content than that of its aqueous extract. From the evaluation of the antibacterial activity, it is noted that six different strains showed a sensitivity towards the extracts (aqueous and ethanolic extract) of Euphorbia hirta; three different strains for Citrus aurantifolia and in the case of extracts of Heterotis rotundifolia, only two strains (Salmonella cholereasius and Klebsielle oxytoca) are not sensitive to any extract. All extracts are nontoxic to shrimp larvae cells. Larval mortality shows the dose-response relationship.
These results justify the therapeutic use of these plants in traditional medium, with interesting antimicrobial and antioxidant properties.

Key - words: Medecinal plant, Phytochemical screening, antibacterial activity, Benin.

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