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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Cell Wall Biology and Utilization Research » Research » Publications at this Location » Publication #347179

Research Project: Removing Limitations to the Efficient Utilization of Alfalfa and Other Forages in Dairy Production, New Bio-Products, and Bioenergy to...

Location: Cell Wall Biology and Utilization Research

Title: Coupling of wet chemistry methods and spectroscopic data for elucidating composition and structure of purified condensed tannins

item Zeller, Wayne
item Mueller-harvey, Irene - University Of Reading
item Hagerman, Ann - Miami University - Ohio

Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/17/2018
Publication Date: 3/22/2018
Citation: Zeller, W.E., Mueller-Harvey, I., Hagerman, A.E. 2018. Coupling of wet chemistry methods and spectroscopic data for elucidating composition and structure of purified condensed tannins. American Chemical Society Abstracts. AGFD 219.

Interpretive Summary:

Technical Abstract: Condensed tannins (CTs) consist of oligomers and polymers of flavan-3-ol subunits varying in hydroxylation patterns, cis- and trans-configuration of C-ring substituents, interflavan bond connections, mean degree of polymerization (mDP), and extent of esterification. Robust analytical methods to determine CT composition and structure are paramount to understanding the biological activity exerted by these secondary plant metabolites in human health, agriculture, and environmental systems. Using a combination of wet-chemistry data from thiolytic degradation, mass spectrometry, and two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy, progress in the structural elucidation of purified CTs has been made. We have previously shown that integration of the 2D-NMR cross-peaks signals for procyanidin/prodelphinidin (PC/PD) and cis/trans flavan-3-ol subunit provides relative ratios that corroborate thiolytic data. Recent progress of CT structure elucidation using these methods in concert allows the identification and content estimations of the terminal flavan-3-ol subunits, the extent of galloylation, ratios of A-type to B-type interflavan linkages, and mDP of purified CT samples. In addition, a second set of 2D-NMR cross-peaks signals (H/C-2) can provide reliable determination of flavan-3-ol cis/trans ratios. These advances will aid in the formulation of CT structure-biological activity relationships.