Caractérisation Structurale De Quelques Métabolites Secondaires Issus De Quelques Plantes De La Famille ‘amarantaceaes ’ Du Sahara Septentrional.

Résumé: In addition to their use as preservatives in food, by replacing the synthetic antioxidants, the antioxidant compounds are involved in the treatment of many diseases. That’s why these compounds are the aim of numerous research works. The work presented in this thesis, contribute to the development of two Saharian medicinal plants of the family amarantaceae (Atriplex Halimus L and Haloxylon scoparium pomel). The preliminary assessment of the phytochemical, parts processed, permit to highlight the presence of some chemical groups. This was confirmed by a quantitative analysis based on the determination of total polyphenols, flavonoids, and condensed tannins. Thus, in order to get a snippet in metabolites of interest, we opted for a liquid-liquid extraction using different solvents by increasing polarity. Chromatographic identification of the butanolic extract of the species Atriplex Halimus L., has allowed to characterize the main phenolic compounds. Two large families of compounds have been highlighted, it is the phenolic acids and flavonoids. Column diaion chromatography and preparative HPLC were primarily two methods for the isolation of vanillic acid. The assessment, in vitro, of the antioxidant activity of the different extracts and fractions, was conducted by six methods, namely: the reduction of the phosphomolybdate, trapping the radical DPPH., the cation-radical ABTS.+, the hydoxy radical OH., the ORAC test and the test of cellular antioxidant. The results showed that extracts of the haloxylon scoparium pomel species present very interesting antioxidant activities. The cytotoxic activity of the extracts on carcinoma cell lines from lung (A-549) and colon (DLD-1) was evaluated, based on their toxicity on healthy cells (WS-1). Evaluation of anti-inflammatory activity shows that the dichloromethane extract of Atriplex halimus L., has a very high activity compared to the Haloxylon scoparium pomel extract. The results of the analysis of the alpha-amylase inhibitors show that the inhibitory activity of the fraction of the Atriplex Halimus L in dichloromethane, has a remarkable inhibition rate.

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