Journal of Chemical Ecology

, 32:2235

Tannin Composition Affects the Oxidative Activities of Tree Leaves

  • Raymond V. Barbehenn
  • Christopher P. Jones
  • Maarit Karonen
  • Juha-Pekka Salminen
Article

DOI: 10.1007/s10886-006-9142-8

Cite this article as:
Barbehenn, R.V., Jones, C.P., Karonen, M. et al. J Chem Ecol (2006) 32: 2235. doi:10.1007/s10886-006-9142-8

Abstract

We examined whether tannin composition plays an important role in explaining the oxidative activities of tree leaves of Acer saccharum (sugar maple) and Quercus rubra (red oak). Sugar maple leaves contained substantial amounts of ellagitannins, condensed tannins, and galloyl glucoses, whereas red oak leaves contained almost exclusively condensed tannins. Oxidative activities of the crude phenolics from both species, and the phenolic fractions from sugar maple, were measured with electron paramagnetic resonance (EPR) spectrometry and UV-visible spectrophotometry. The two assays produced similar results: (1) sugar maple phenolics produced larger semiquinone radical concentrations,and higher semiquinone decay rates and browning rates than did red oak phenolics;(2) ellagitannin levels were positively associated with the three measures of oxidative activity; and (3) condensed tannin and galloyl glucose levels were negatively associated with these measures. The negative relationship between condensed tannin levels and oxidative activity resulted from the antioxidant effects of condensed tannins on hydrolyzable tannins; several purified condensed tannins significantly decreased the concentrations of semiquinone radicals and browning rates of pedunculagin (an ellagitannin) and pentagalloyl glucose. As expected, whole-leaf extracts from sugar maple produced elevated levels of semiquinone radicals, but none were observed in red oak extracts when the two species were compared with an EPR time-course assay. We conclude that the oxidative activities of tree leaves may be affected by tannin composition, and that the prooxidant activity of ellagitannins may be decreased by co-occurring condensed tannins.

Keywords

TanninEllagitanninCondensed anninPhenolic compoundsOxidationSemiquinone radicalTreesAcer saccharumQuercus rubraHerbivoreCaterpillar

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Raymond V. Barbehenn
    • 1
  • Christopher P. Jones
    • 1
  • Maarit Karonen
    • 2
  • Juha-Pekka Salminen
    • 2
  1. 1.Departments of Molecular, Cellular and Developmental Biology and Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborUSA
  2. 2.Laboratory of Organic Chemistry and Chemical Biology, Department of ChemistryUniversity of TurkuTurkuFinland