Isolation and identification of new anthraquinones from Rhamnus alaternus L and evaluation of their free radical scavenging activity |
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Authors: | Rebai Ben Ammar Tomofumi Miyamoto Leila Chekir-Ghedira Kamel Ghedira Marie-Aleth Lacaille-Dubois |
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Institution: | 1. Department of Biological Sciences, College of Sciences, King Faisal University, Al Hufuf, Saudi Arabia;2. Laboratoire des Plantes Aromatiques et Médicinales, Centre de Biotechnologie de Borj Cédria, Hammam-lif, Tunisia;3. Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan;4. Unité de Substances Naturelles Bioactives et Biotechnologie (UR12ES12), Faculté de pharmacie de Monastir, Université de Monastir, Monastir, Tunisia;5. Laboratory of Cellular and Molecular Biology, Faculty of Dental Medicine, University of Monastir, Monastir, Tunisia;6. Laboratoire de Pharmacognosie, UMIB, UFR des Sciences de Santé, Université de Bourgogne Franche-Comté, Dijon Cedex, France |
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Abstract: | From the butanolic and the ethyl acetate extracts of Rhamnus alaternus L root bark and leaves, three new anthraquinone glycosides, alaternosides A-C (1,4,6,8 tetrahydroxy-3 methyl anthraquinone 1-O-ß-D-glucopyranosyl-4,6-di-O-α-L-rhamnopyranoside (1); 1,2,6,8 tetrahydroxy-3 methyl anthraquinone 8-O-ß-D-glucopyranoside (2) and 1, 6 dihydroxy-3 methyl 6 2′-Me (heptoxy)] anthraquinone (3)) were isolated and elucidated together with the two known anthraquinone glycosides, Physcion-8-O-rutinoside (4) and emodin-6-O-α-L-rhamnoside (5) as well as with the known kaempferol-7-methylether (6), β-sitosterol (7) and β-sitosterol-3-O-glycoside (8). Their chemical structures were elucidated using spectroscopic methods (1D-, 2D-NMR and FAB-MS). Free radical scavenging activity of the isolated compounds was evaluated by their ability to scavenge DPPH. free radicals. Compounds (3), (4) and (6) showed the highest activity with IC50 values of 9.46, 27.68 and 2.35 μg/mL, respectively. |
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Keywords: | Rhamnus alaternus L rhamnaceae anthraquinone glycosides alaternosides A-C NMR FAB-MS DPPH scavenging activity |
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