Ann E. Hagerman
Tannins, plant polyphenols, antioxidants
My research is focused on the plant natural products known as tannins, or polyphenols. Humans may consume as much as 1 gram of tannin per day from fruits, chocolate, tea, and wine. Herbivorous animals and insects consume large amounts of leaf tannin, and tannin enters the soil ecosystem from decaying leaves and root exudates. The biochemical consequences of polyphenolics in these diverse biological arenas 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 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 complex matrices like soils; 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 human digestion, in animals, and in soil ecosystems.
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.
Close, D.C.; McArthur, C.; Hagerman, A.E.; Davies, N.W.; Beadle, C.L. Phenolic acclimation to ultraviolet-A irradiation in Eucalyptus nitens seedlings raised across a nutrient environment gradient. Photosynthetica 2007, 45, 36-42.
Ferreira, D.; Gross, G.G.; Hagerman, A.E.; Kolodzieg, H.; Yoshida, T. Tannins and related polyphenols: Perspectives on their chemistry, biology, ecological effects and human health protection. Phytochemistry 2008, 69, 3006-3008.
Molyneux, R.J.; Mahoney, N.; Kim, J.H.; Campbell, B.C.; Hagerman, A.E. Antioxidant constituents in tree nuts: health implications and aflatoxin inhibition. ACS Symp. Ser. 2008, 993, 181-191.
Schweitzer, J.A.; Madritch, M.D.; Bailey, J.K.; LeRoy, C.; Fischer, D.G.; Rehill, B.J.; Lindroth, R.L.; Hagerman, A.E.; Wooley, S.C.; Hart, S.C.; Whitham, T.G. From genes to ecosystems: the genetic basis of condensed tannins and their role in nutrient regulation in a Populus model system. Ecosysytems 2008, 11, 1005-1020.
Wisman, K.N.; Perkins, A.A.; Jeffers, M.D.; Hagerman, A.E. Accurate assessment of the bioactivities of redox-active polyphenolics in cell culture. J. Agric. Food Chem. 2008, 56, 7831-7837.
Alessio, H.M.; Schweitzer, N.B.; Snedden, A.M.; Callahan, P.; Hagerman, A.E. Revisiting influences on tumor development: focusing on laboratory housing. J. Am. Assoc. Lab. Anim. Sci. 2009, 48, 258-262.
Halvorson, J.J.; Gonzalez, J.M.; Hagerman, A.E.; Smith, J.L. Sorption of tannin and related phenolic compounds and effects on soluble-N in soil. Soil Biol. Biochem. 2009, 41, 2002-2010.
Heinaaho, M.; Hagerman, A.; Julkunen-Tiitto, R. Effect of different organic farming methods on the phenolic composition of sea buckthorn berries. J. Agric. Food Chem. 2009, 57, 1940-1947.
Kendrick, E.L.; Shipley, L.A.; Hagerman, A.E.; Kelley, L.M. Fruit and fiber: The nutritional value of figs for a small tropical ruminant, the blue duiker (Cephalophus monticola). African Journal of Ecology 2009, 47, 556-566.
Zhang, J.; Li, L.; Kim, S.; Hagerman, A.E.; Lu, J. Anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucose. Pharm. Res. 2009, 26, 2066-2080.
Kinraide, T.; Hagerman, A. Interactive intoxicating and ameliorating effects of tannic acid, aluminum (Al3+), copper (Cu2+) ad selenate (SeO42-) in wheat roots. A descriptive and mathematical assessment. Physiol. Plantarum 2010, 139, 68-79.
Li, C.; Trombley, J.D.; Schmidt, M.A.; Hagerman, A.E. Preparation of an acid butanol standard from fresh apples. J. Chem. Ecol. 2010, 36, 453-460.
Li, C.; Leverence, R.; Trombley, J.D.; Xu, S.; Yang, J.; Tian, Y.; Reed, J.D.; Hagerman, A.E. High molecular weight persimmon (Diospyros kaki L.) proanthocyanidin: A highly galloylated, A-linked tannin with an unusual flavonol terminal unit, myricetin. J. Agric. Food Chem. 2010, 58, 9033-9042.
Mahoney, N.; Molyneux, R.J.; Kim, J.H.; Campbell, B.C.; Waiss, A.C.; Hagerman, A.E. Aflatoxigenesis induced in Aspergillus flavus by oxidative stress and reduction by phenolic antioxidants from tree nuts. World Mycotoxin J. 2010, 3, 49-57.
Simonsen, M.L.; Alessio, H.M.; White, P.; Newsom, D.L.; Hagerman, A.E. Acute physical activity effects on cardiac gene expression. Exp. Physiol. 2010, 95, 1071-1080.
Scioneaux, A.N.; Schmidt, M.A.; Moore, M.A.; Lindroth, R.L.; Wooley, S.C.; Hagerman, A.E. Qualitative variation in proanthocyanidin composition of Populus species and hybrids: Genetics is the key. J. Chem. Ecol. 2011, 37, 57-70.