Sesquiterpene lactones and phenolic compounds from Centaurea maroccana

2 pages.-- Published in Khimiya Prirodnykh Soedinenii, No. 6, p. 621, November–December, 2007.Plants of the genus Centaurea (Asteraceae) are interesting for the variety of their chemical composition and for their biological activity. The genus Centaurea, which contains more than 700 species, is represented by 45 species in Algeria. Centaurea maroccana L., which was not phytochemically investigated, is an endemic species of Algeria and Morocco, flowering from April to June. It was collected from the area of Biskra in the South of Algeria in April 2002 and authenticated by Prof. M. Kaabeche (Biology department, University of Setif, Algeria)

A flavonoid with high antioxidant effect from Centaurea acaulis L.

The flavonoid glycosides: patuletin 7-O-β-glucopyranoside 3, hispidulin 7-O-β-glucopyranoside 2 together with hispidulin 1, were isolated from the n-butanol soluble part of the aqueous-MeOH extract of the flowering aerial parts of C. acaulis L. (Asteraceae), an endemic species of Algeria and Tunisia. The structures were established by chemical and spectral analysis, mainly HR-ESIMS, UV and NMR experiments (COSY, NOESY, HSQC and HMBC). Patuletin 7-O-β-glucopyranoside showed a high antioxidant effect, especially scavenging of DPPH (IC50 = 4.83 µg/ml) anions and inhibition of lipid peroxidation (51.93%.). Those various antioxidant activities were compared to vitamin C (standard antioxidant)

Maroccanin: A new γ-lactone and other constituents from Centaurea maroccana ball. (Asteraceae)

A new γ-lactone named maroccanin (1) together with 5 known compounds : scopoletin (2); 8α-[2’- hydroxymethyl-2’-butenoyloxy]-dehydromelitensin (3); 11,13-dehydromelitensin (4); 8α-[2’-hydroxymethyl-2’- butenoyloxy]-sonchucarpolide (5) and 5Hα,6Hβ,7Hα,-15-hydroxy-8α-(1’,2’-dihydroxyethyl-acryloxy)-elema1(2),3(4),11(13)-trien-6,12-olide (6), were isolated from the chloroform soluble part of the aqueous-MeOH extract of the flowering aerial parts of C. maroccana Ball. (Asteraceae), an endemic species of the North of the Sahara. The structures were established by chemical and spectral analysis, mainly HR-ESIMS, HREIMS,UV and NMR experiments (COSY, NOESY, HSQC and HMBC). The compounds 3 and 5 are new for the genus Centaurea.This work was supported by Algerian FNR program (PNR 8u250/4211, ATRST contract 26/70) and by the NATO Science project (Valorisation of Phytochemical Natural Resources in Algeria)