Résumé:
From the photochemical study of 3 Algerian plants Euphorbia clementei (Euphorbiaceae), Eryngium tricuspidatum (Apiaceae), Cladanthus mixtus (Asteraceae),
42 compounds from which 3 are new, have been isolated and identified by the use of chromatographic techniques of separation and purification (CC, TLC, HPLC and EPC) and by spectral techniques e.g UV, NMR 1D and 2D, MS HRESI. The latex and CHCL3 extracts of E. clementei led to the isolation of 7 compounds, one new diterpenoid, 2 monoterpenes and 4 triterpenes. 8 Compounds (3 phenols glycosyls from which two are new, 2 monoterpenes, 1 coumarin and 2 flavonoids) have been isolated from the methanol extract of E. tricuspidatum. The phytochemical investigation of ethyl the acetate and n_butanol extracts of C. mixtus allowed the isolation and identification of 27 compounds from which 15 flavonoids, 5 phenolic acids, 5 quinic acids, 1 phenol glycoside and 1 monoterpene glycoside.
