个人简介

Ph.D., Purdue University (1980)

研究领域

Polyphenolic biochemistry, antioxidant activity

Tannins are plant natural products that have molecular weights of at least 500 g/mol, that have more than one phenolic moiety, and that form stable complexes with proteins. Tannins are constituents of the larger class of plant products known as polyphenolics, but tannins are unique in their ability to precipitate proteins. They are also potent antioxidants and chelate metals such as iron or copper. We are interested in the bioactivities of tannins found in the human diet (tea, wine, chocolate, fruits) and in the ecological significance of tannins found in natural systems (soils, herbivory). In particular, we use purified tannins to establish structure-activity relationships with the long term goal of understanding of tannins as individual bioactive compounds. In the diagram above, the precipitation data shows that green tea polyphenol epigallocatechin gallate (EGCg) does not precipitate protein efficiently compared to condensed tannin procyanidin (PC) or gallotannin pentagalloyl glucose (PGG). However, EGCg binds selectively to the hydrophobic pocket of serum albumin (right). Binding to serum albumin stabilizes EGCg for transit through the blood and modulates albumin-related properties such as tendency to form glycated adducts under conditions of high blood sugar (diabetes). Our tools to probe selective interaction range from fluorescence spectroscopy to MALDI-TOF mass spectrometry.

近期论文

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Fluorescence as a probe of (-)-epigallocatechin gallate-serum albumin interactions (2014) Comparison of gene and protein expressions in rats residing in standard cages with those having access to an exercise wheel (2014) Molecular weight and protein-precipitating ability of condensed tannins from warm-season perennial legumes (2014) Retention of tannin-C is associated with decreased soluble nitrogen and increased cation exchange capacity in a broad range of soils (2013) The interaction of a polymeric persimmon proanthocyanidin fraction with Chinese cobra PLA2 and BSA (2013) Interactions between plasma proteins and naturally occuring polyphenols (2013) Soil microbial communities respond different to three chemically defined polyphenols (2013) Metal mobilization in soil by two structurally defined polyphenols (2012) Stability of polyphenols epigallocatechin gallate and pentagalloyl glucose in a simulated digestion system (2012) Changes in soluble-N in forest and pasture soil after repeated applications of tannins and related phenolic compounds (2012) Fifty years of polyphenol-protein complexes (2012) Kinetics and binding capacity of six soils for structurally defined hydrolyzable and condensed tannins and related phenols (2012) Sorption of tannin and related phenolic compounds and effects on extraction of soluble-N in soil amended with several carbon sources (2012) High molecular weight persimmon tannin is a potent antioxidant both ex vivo and in vivo (2012) Caution against determining tannins in soil using the protein precipitable phenolics assay (2011) Polyphenols, ethnomedicine, and benefit sharing (2011) Capillary electrophoresis methods for the determination of covalent polyphenol-protein complexes (2011) Repeated applications of tannins and related phenolic compounds are retained by soil and affect cation exchange capacity (2011) Probing the interaction of polyphenols with lipid bilayers by solid-state NMR spectroscopy (2011) Qualitative variation in proanthocyanidin composition of Populus species and hybrids: Genetics is the key (2011)