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Start date: 2024Subject: search.filters.subject.NMR

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    Chemical constituents of Centaurea dissecta Ten. and sesquiterpenes chemotaxonomic significance
    (PERGAMON-ELSEVIER SCIENCE LTD, 2024-03-06) Badaoui, Mohamed Ibrahim; Chabani, Sonia; Alabdul Magid, Abdulmagid; Voutquenne-Nazabadioko, Laurence; Sayagh, Charlotte; Harakat, Dominique; Haba, Hamada
    The phytochemical investigation of Centaurea dissecta Ten. led to the isolation of thirty-two compounds of diverse chemical classes including two sesquiterpene lactones (1, 2), two sesquiterpenes (3, 4), twelve flavonoids (5–16), one lignan (17), twelve phenols (18–29), one triterpene (30) and two phytosterols (31, 32) from the EtOAc and n-BuOH soluble fractions of the 70% aqueous ethanol extract. Furthermore, the phenolic and flavonoid contents were measured for the petroleum ether, EtOAc and n-BuOH soluble fractions. The chemical structures of these compounds were determined by using a combination of NMR spectroscopic and mass spectrometry (ESI-MS) analyses, as well as by comparison with literature values. Only apigenin (15) was isolated previously from Centaurea affinis, and all other compounds were isolated for the first time from this species. Noticeably, ethyl ferulate (20), ethyl caffeate (21), synapyl aldehyde (22), coniferyl aldehyde (23), 2,3-dihydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (24), and C-veratroylglycol (25), have not been reported from the genus Centaurea. All compounds have been previously isolated in various plants belonging to the Asteraceae family. Meanwhile, the chemotaxonomic significance of the isolated compounds was summarized.
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    A new 7,9′-monoepoxylignan glucoside and other phytochemicals from Centaurea granatensis and their chemotaxonomic significance
    (PERGAMON-ELSEVIER SCIENCE LTD, 2024-07-30) Belaid, Meriem; Mouffouk, Soumia; Chabani, Sonia; Mouffouk, Chaima; Benkhaled, Mohammed; Haba, Hamada
    The chemical study of Centaurea granatensis Boiss. ex DC. allowed the isolation and structural elucidation of eighteen secondary metabolites (1-18) from ethyl acetate (EtOAc) and n-butanol (n-BuOH) extracts. These compounds are divided into one new epoxylignan glucoside (1) and seventeen known phytochemicals including seven flavonoids (2-8), four triterpenes (9-12), and six phytosterols (13-18). Structures of the isolates were identified using various spectroscopic methods, namely 1D NMR (1H and 13C), 2D NMR (HSQC, 1H-1H COSY, HMBC, and NOESY), and mass spectrometry (HR-ESIMS), as well as by comparison with literature data. The obtained results showed the abundance of triterpenoids and flavonoids particularly flavones in C. granatensis. Apigenin (3) could be used as a chemotaxonomic marker of this genus due to its presence in approximately forty plant species. Furthermore, tiliroside (2) and stigmasteryl-3-O-β-D-glucoside-6′-palmitate (18) were first detected in Centaurea genus, but had previously been found in species of the Asteraceae family. Additionally, the chemotaxonomic significance of all isolated molecules was fully discussed.