The Phytochemical Investigation Of The Algerian Medicinal Plant Fraxinus Xanthoxyloides

Résumé: The nature was and still an interesting source of potential chemotherapeutic agents. Whatever the reasons for the presence of these compounds in nature, they provide invaluable resources that have been used to find new drug molecules. In this context, the Algerian medicinal plant Faxinus xanthoxyloides of the Oleaceae family has been selected for phytochemical investigation and anti-oxidant screening. This work allowed the isolation by chromatographic methods (TLC, PTLC, CC and LPLC), and the characterization by spectroscopic analysis (NMR and MS) of 17 secondary metabolites including 2 coumarin-secoiridoid glucosides, 2 secoiridoids, 3 coumarins, 2 flavonoids, 4 phenylethanoids, 2 phenylpropanoids and 2 lignans. 10 compounds have been isolated from the methanolic extract of the stem bark from which one new structure was established as a coumarin-secoiridoid diglucosides. The known secondary metabolites consist of 1 coumarin-secoiridoid, 2 coumarins, 2 phenylethnoids, 2 phenylpropanoids and 2 lignans. From the methanolic extract of the leaves 9 secondary metabolites have been identified. They were devided into 2 secoiridoids with oleoside skeleton, 3 coumarins among them 2 common glucosides with the bark and one coumarin aglucone, two flavonoid diglucosides and two phenylethanoids. The molecular structures of the isolated compounds 1-17 were mainly elucidated by the use of NMR techniques 1D and 2D (1H, 13C, DEPT, HSQC, HMBC and ROESY), high resolution mass spectrometry (HR-ESI-MS), measurement of the optical rotation [α]D20 and by comparison with the literature data. The anti-oxidant activity of leaves and bark extracts was estimated by the DPPH free radicals scavenging and ABTS radical cation decolorization assay and the results showed that bark extracts had an interesting activity. Finally, it is important to indicate that among known compounds reported in the literature, one phenylethanoide and two lignan glucosides have been found for the first time in Fraxinus genus. Furthermore, this study contributes to determine the chemical composition of this genus.

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