title: Antioxidant oligomeric proanthocyanidins from Cistus salvifolius.
abstract: The purified proanthocyanidin oligomers of Cistus salvifolius herb extract accounted for 78% of the total proanthocyanidins and 73% of the total antioxidant activity of this extract. To elucidate the structure of the oligomer, it was depolymerized by acid catalysis in the presence of phloroglucinol. The structures of the resulting flavan-3-ols and phloroglucinol adducts were determined on the basis of 1D- and reverse 2D-NMR (HSQC, HMBC) experiments of their peracetylated derivatives, MALDI-TOF-MS and CD spectroscopy. These observations resulting from the degradation with phloroglucinol were confirmed by 13C NMR spectroscopy of the oligomer. The mean molecular weight of the higher oligomeric fraction was estimated to be 5-6 flavan-3-ol-units.
authors.affiliation: Faculty of Pharmacy, The University of Petra, PO Box 961343, Amman, Jordan. f_qadan@yahoo.com
authors.forename: Fadi
authors.initials: F
authors.lastname: Qa'Dan
authors.forename: Frank
authors.initials: F
authors.lastname: Petereit
authors.forename: Kenza
authors.initials: K
authors.lastname: Mansoor
authors.forename: Adolf
authors.initials: A
authors.lastname: Nahrstedt
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D029758:Cistus / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D044948:Flavonols / Q000737:chemistry; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009904:Optical Rotation; D010696:Phloroglucinol / Q000737:chemistry; D044945:Proanthocyanidins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000975:Antioxidants; D044948:Flavonols; D044945:Proanthocyanidins; D010696:Phloroglucinol