Isolation and structure elucidation of highly antioxidative 3,8″-linked biflavanones and flavanone-C-glycosides from garcinia buchananii bark

Timo D. Stark, Toshiaki Matsutomo, Sofie Lösch, Paul A. Boakye, Onesmo B. Balemba, Sofie P. Pasilis, Thomas Hofmann

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

The aim of this study was to identify antioxidants from Garcinia buchananii bark extract using hydrogen peroxide scavenging and oxygen radical absorbance capacity (ORAC) assays. LC-MS/MS analysis, 1D- and 2D-NMR, and circular dichroism (CD) spectroscopy led to the unequivocal identification of the major antioxidative molecules as a series of three 3,8″-linked biflavanones and two flavanone-C-glycosides. Besides the previously reported (2R,3R,2″R, 3″R)-naringenin-C-3/C-8″ dihydroquercetin linked biflavanone (GB-2; 4) and (2R,3S,2″R,3″R)-manniflavanone (3), whose stereochemistry has been revised, the antioxidants identified for the first time in Garcinia buchananii were (2R,3R)-taxifolin-6-C-β-D-glucopyranoside (1), (2R,3R)-aromadendrin-6-C-β-D-glucopyranoside (2), and the new compound (2R,3S,2″S)-buchananiflavanone (5). The H 2O 2 scavenging and the ORAC assays demonstrated that these natural products have an extraordinarily high antioxidative power, especially (2R,3S,2″R,3″R) -manniflavanone (3) and GB-2 (4), with EC 50 values of 2.8 and 2.2 μM, respectively, and 13.73 and 12.10 μmol TE/ μmol. These findings demonstrate that G. buchananii bark extract is a rich natural source of antioxidants.

Original languageEnglish
Pages (from-to)2053-2062
Number of pages10
JournalJournal of agricultural and food chemistry
Volume60
Issue number8
DOIs
StatePublished - 29 Feb 2012

Keywords

  • (2R,3S,2″R)-3″ R)-manniflavanone
  • (2R,3S,2″S)- buchananiflavanone
  • 3,8″-linked biflavanones
  • Antioxidants
  • Flavanone-6-C-glycosides
  • GARCINIA buchananii

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