Résumé:
This work belongs to our research program on the phytochemical study of Centaurea genus
(Compositae). The species of this genus, showed their wealth of bioactive secondary metabolites.
Our study, which concerns the isolation and the structural determination of sesquiterpene
lactones and flavonoids from the ethyl acetate soluble part of the aqueous-EtOH extract of the
aerial parts of Centaurea nicaeensis var. walliana M, constitute a contribution in this field and
supplement the results obtained in our laboratory from the chloroform soluble part which led to
the isolation and the structural establishment of two flavonoids.
After maceration of flowers and leaves of this plant, filtration, concentration and successive
extractions with chloroform, ethyl acetate and n-butanol, the ethyl acetate extract was submitted
to separation and purification by column and thin layer chromatography on silica gel 60.
This work led to the isolation in the native state of 5 compounds which were:
• A flavone : apigenin
• Two flavone glycosides : apigenin 7-(6’’-methylglucuronide) and
apigenin 4’-(6’’-methylglucuronide)
• A sesquiterpene lactone of elemanolide type-skeleton : melitensin
• A cyanogenic compound : prunasin
The structures were established by the combination of 1 H NMR, 13 C NMR, 2D NMR
experiments, mass spectrometry and UV-Vis spectroscopy data.
It is important to note, that apigenin 4’-(6’’-methylglucuronide) is new and then, was not
described elsewhere.
