Planta Med 2006; 72 - P_308
DOI: 10.1055/s-2006-950108

Antioxidant oligomeric proanthocyanidins from Cistus salvifolius

F Qa'dan 1, F Petereit 2, K Mansour 3, A Nahrstedt 2
  • 1Faculty of Pharmacy, The University of Petra, P.O.Box: 961343 Amman-Jordan
  • 2Institut fuer Pharmazeutische Biologie und Phytochemie, Hittorfstrasse 56, 48149 Muenster, Germany
  • 3School of Pharmacy and Pharmaceutical Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK

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 [1]. To elucidate the structure of the oligomer, it was depolymerized by acid catalysis in the presence of phloroglucinol [2]. 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 [3]. These observations resulting from the degradation with phloroglucinol were confirmed by 13C-NMR spectroscopy of the oligomer (4). The mean molecular weight of the higher oligomeric fraction was estimated to be 5–6 flavan-3-ol-units.

Acknowledgments: F Qa'dan would like to acknowedge gratefully the DAAD and the Deanship of Research at the University of Petra for funds and grants (Grant No.1/5/2002). We wish to acknowlege also the help of Dr.H.Lahl, Ms.M.Heim (Inst.f. Pharmazeutische Chemie, Münster) and Dr. Brian Lockwood (School of Pharmacy, Manchester) for the NMR-spectra.

References: 1. Al-Khalil, S. (1995), Int. J. Pharmacognosy 33(4): 317–323. 2. Kennedy, J.A., Graham, P.J. (2001), J. Agric. Food Chem. 49:1740–1746. 3. Balas, L., Vercauteren, J. (1994), Magn. Reson. Chem. 32: 386–393. 4. Eberhardt, T., Young, R.A. (1994), J. Agric. Food Chem. 42: 1704–1708.