Ann E. Hagerman, Professor Ph.D. (1980) Purdue University 513-529-2827 HAGERMAE@MUOHIO.EDU http://www.users.muohio.edu/~hagermae

Tannins, plant polyphenolics, antioxidants

My research is focused on the plant natural products known as tannins, or polyphenolic compounds. Humans may consume as much as 1 gram of tannin per day via plant-based foods and beverages. The biochemical consequences of polyphenolic consumption are not well understood, although both positive (antioxidants) and negative (antinutrient) activities have been ascribed to various tannins.

The strategies employed in my research include isolation and characterization of tannins from food plants in sufficient quantities for in vivo and in vitro experimentation; development of new analytical techniques for quantifying tannins in feeds, foods and beverages; and elucidation of mechanisms of action of tannins in biochemical systems.

The antioxidant activities of phenolic compounds have led to claims that consumption of foods and beverages rich in polyphenolics is beneficial. This recommendation contrasts starkly with earlier claims that dietary tannins were potent antinutrients, interfering with both protein and iron absorption. The detailed mechanistic studies of well-characterized tannins that we conduct are devised to establish desirable levels and types of dietary tannins to balance beneficial and detrimental activities.

In addition to laboratory analysis, we conduct in vivo studies to explore the role of tannins in minimizing oxidative damage. We have measured a range of biomarkers of oxidative stress, and have identified some key tissues that may be protected by dietary tannins.

References

N. B. Schweitzer, H. M. Alessio, S. D. Berry, K. Roeske, and A. E. Hagerman, “Exercise-Induced Changes in Cardiac Gene Expression and its Relation to Spatial Maze Performance”, Neurochemistry International, 48, 9-16 (2006).

P. G. Peters, H. M. Alessio, A. E. Hagerman, T. Ashton, S. Nagy, and R. L. Wiley, “Short-term Isometric Exercise Reduces Systolic Blood Pressure in Hypertensive Adults:  Possible Role of Reactive Oxygen Species”, International Journal of Cardiology, 110, 199-205 (2006).

K. Cai, A. E. Hagerman, R. E. Minto, and A. Bennick, “Decreased Polyphenol Transport Across Cultured Intestinal Cells by a Salivary Proline-Rich Protein”, Biochemical Pharmacology, 71, 1570-1580 (2006).

R. A. Hagerman, N. J. Waring, R. A. Willis, and A. E. Hagerman, “Ubiquinone Accumulates in the Mitochondria of Saccharomyces Cerevisiae Strains Mutated in the Ubiquinone Binding Protein, Qcr8p”, Biochemical and Biophysical Research Communications, 344, 241-245 (2006).

R. V. Barbehenn, C. P. Jones, A. E. Hagerman, M. Karonen, and J.-P. Salminen, “Ellagitannins Have Greater Oxidative Activities than Condensed Tannins and Galloyl Glucoses at High pH:  Potential Impact on Caterpillars”, Journal of Chemical Ecology, 32, 2253-2267 (2006).

Close, D.C.; McArthur, C; Hagerman, A.E.; Fitzgerald, H. Differential stratification of leaf chemistry in eucalypt seedlings due to variation in whole-plant nutrient availability.  Phytochemistry.  2005 66, 215-221.

Chen, Y; Hagerman, A. E.  Reaction pH and protein affect the oxidation products of β-pentagalloyl glucose.  Free Radical Research.  2005 39, 117-124.

Schweitzer , N.B.; Alessio, H.M.; Hagerman, A.E.; Roy, S.; Sen, C.K.; Nagy, S.; Byrnes, R.; Woodward, J.L.; Wiley, R.L.  Access to exercise and its relation to cardiovascular health and gene expression in laboratory animals.  Life Sciences 2005 77, 2246-2261.

  This page was last modified on February 08, 2008. on