Recent Advances in Polyphenol Research, Volume 3

Plant polyphenols are secondary metabolites that constitute one of the most common and widespread groups of natural products. They express a large and diverse panel of biological activities including beneficial effects on both plants and humans. Many polyphenols, from their structurally simplest representatives to their oligo/polymeric versions (also referred to as vegetable tannins) are notably known as phytoestrogens, plant pigments, potent antioxidants, and protein interacting agents. Sponsored by Groupe Polyphénols, this publication, which is the third volume in this highly regarded Recent Advances in Polyphenol Research series, is edited by Véronique Cheynier, Pascale Sarni-Manchado, and Stéphane Quideau (the current President of Groupe Polyphénols). Like their predecessors, they have once again put together an impressive collection of cutting-edge chapters written by expert scientists internationally respected in their respective field of polyphenol sciences. This Volume 3 provides the latest information and opinion on the following major research topics about polyphenols: Organic chemistry and physical chemistry Biosynthesis, genetics and metabolic engineering The role of polyphenols in plants and ecosystems Health and nutrition Analysis and metabolomics Chemists, biochemists, plant scientists, pharmacognosists and pharmacologists, biologists, ecologists, food scientists and nutritionists will all find this book an invaluable resource. Libraries in all universities and research institutions where these disciplines are studied and taught should have copies on their bookshelves.

Contributors xv Preface xix 1 Plant Phenolics: A Biochemical and Physiological Perspective 1 Vincenzo Lattanzio, Angela Cardinali and Vito Linsalata 1.1 The general phenolic metabolism in plants 1 1.2 Effect of non-freezing low temperature stress on phenolic metabolism in crop plants 6 1.3 Plant phenolics as defence compounds 11 1.3.1 Phenolic-mediated induced resistance of apples against fungal pathogens 12 1.3.2 Contribution of vigna phenolics to plant protection against insects 16 1.4 Diversion of carbon skeletons from primary to phenolic-related secondary metabolism 19 1.4.1 Metabolic costs of adaptive responses to adverse environmental conditions 21 1.4.2 Transduction pathway between nutrient depletion and enhanced polyphenol content 24 References 26 2 Polyphenols: From Plant Adaptation to Useful Chemical Resources 41 Alain-Michel Boudet 2.1 The emergence of phenolic metabolism and the adaptation of plants to a terrestrial environment 41 2.2 The shikimate pathway: a complex and subtle interface between primary metabolism and phenolic metabolism 47 2.2.1 Quinic acid, a specific component of higher plants 49 2.2.2 The postchorismate branch of the shikimate pathway leading to phenylalanine: one or two metabolic routes in plants? 53 2.2.2.1 Intracellular location of enzymes 54 2.2.2.2 Complex and new regulatory mechanisms in the shikimate pathway 55 2.3 Plant (poly)phenols: a diversified reservoir of useful chemicals 56 2.3.1 The health-promoting properties of polyphenols 57 2.3.2 A new time for lignocellulosics utilization through biotechnology 58 2.3.2.1 Biomass pretreatment and enzymatic conversion of polysaccharides 59 2.3.2.2 Lignins: degradation, bioconversion 60 2.3.2.3 The fermentation step towards the production of bioalcohols 61 2.3.2.4 Biorefinery pilot plants 61 2.3.2.5 Quality and availability of the upstream resource 61 2.3.2.6 Future prospects 62 2.3.3 Chemical and catalytic valorization of polyphenols 63 2.4 Concluding remarks 63 Acknowledgments 64 References 64 3 Fifty Years of Polyphenol–Protein Complexes 71 Ann E. Hagerman 3.1 Introduction 71 3.2 Precipitable complexes 74 3.3 Soluble complexes 76 3.4 Proline-rich proteins 78 3.5 Mechanisms of binding 79 3.6 Stoichiometry of binding 80 3.7 Protein conformation 82 3.8 Covalent tannin–protein complexes 83 3.9 Conclusions 90 Acknowledgments 91 References 91 4 Chemistry of Flavonoids in Color Development 99 Kumi Yoshida, Kin-ichi Oyama and Tadao Kondo 4.1 Introduction 99 4.2 Synthetic studies on anthocyanins toward polyacylated pigments 103 4.2.1 Previously reported syntheses of anthocyanins 103 4.2.2 Synthesis of anthocyanin using biomimetic oxidation 105 4.2.3 Transformation of flavonol derivatives to anthocyanins via a flavenol glycoside 107 4.3 Synthesis of copigments for studying blue color development 109 4.3.1 Copigmentation in metalloanthocyanins 110 4.3.2 Synthesis of glycosylated flavones 112 4.3.3 Chiral recognition in metalloanthocyanin formation 114 4.3.4 Synthesis of acylquinic acid derivatives for studies on hydrangea coloration 118 4.4 Conclusion 122 Abbreviations 123 Acknowledgments 124 References 124 5 Colouring up Plant Biotechnology 131 Cathie Martin, Yang Zhang, Laurence Tomlinson, Kalyani Kallam, Jie Luo, Jonathan D.G. Jones, Antonio Granell, Diego Orzaez and Eugenio Butelli 5.1 Introduction 131 5.2 Plant production of anthocyanins 132 5.2.1 Synthesis of anthocyanins 132 5.2.2 Transport of anthocyanins 132 5.2.3 Decoration of anthocyanins 132 5.2.4 Factors affecting the colour of anthocyanins 134 5.2.5 Copigmentation 135 5.2.6 Transcriptional regulation of anthocyanin biosynthesis 135 5.3 Engineering anthocyanin production in plants 137 5.3.1 An in vivo reporter of promoter activity 137 5.3.2 Biofortified crops 138 5.3.3 Visually traceable system for VIGS analysis of gene function 138 5.4 Conclusions 139 Acknowledgements 139 References 139 6 Anthocyanin Biosynthesis, Regulation, and Transport: New Insights from Model Species 143 Lucille Pourcel, Andrés Bohórquez-Restrepo, Niloufer G. Irani and Erich Grotewold 6.1 Anthocyanins and related pigments in model plant species 143 6.1.1 General characteristics of anthocyanins 143 6.1.2 Anthocyanin biosynthetic enzymes 145 6.1.3 Anthocyanins in Arabidopsis 146 6.2 Transcriptional regulation of anthocyanin biosynthetic genes 147 6.2.1 Maize 147 6.2.2 Arabidopsis 149 6.2.3 Petunia 150 6.2.4 Snapdragon 150 6.3 Anthocyanin transport and subvacuolar localization 151 6.4 Concluding remarks 154 References 154 7 Shedding Light on the Black Boxes of the Proanthocyanidin Pathway with Grapevine 161 Yung-Fen Huang, Véronique Cheynier and Nancy Terrier 7.1 Tools available on grape to study PA biosynthesis 161 7.1.1 Grape PAs 162 7.1.1.1 Grape PA structure 162 7.1.1.2 Grape PA variations according to genotype, tissue and development 164 7.1.2 Grape genetic and genomic tools 166 7.2 Biosynthesis 167 7.2.1 Enzymes of the pathway 167 7.2.2 Transport and storage of PAs 169 7.2.3 PA polymerisation 174 7.2.3.1 Nature of the extension units 174 7.2.3.2 Enzymatic or chemical polymerisation 175 7.2.3.3 Subcellular localisation of polymerisation 176 7.3 Regulation of the pathway 176 References 182 8 Phenolic Compounds in Plant Defense and Pathogen Counter-defense Mechanisms 191 Fouad Daayf, Abdelbasset El Hadrami, Ahmed F. El-Bebany, Maria A. Henriquez, Zhen Yao, Holly Derksen, Ismaïl El-Hadrami and Lorne R. Adam 8.1 Introduction 191 8.2 Plant defenses and pathogen counter-defenses 192 8.3 Phenolic-related plant responses to pathogens 194 8.3.1 Cotton–Verticillium dahliae 194 8.3.2 Cucumber—Sphaerotheca fuliginea 195 8.3.3 Chickpea—Fusarium oxysporum f. sp. ciceris 196 8.3.4 Potato–Verticillium dahliae 196 8.3.5 Potato–Phytophthora infestans 197 8.3.6 Sunflower–Verticillium dahliae 198 8.3.7 Date palm–Fusarium oxysporum f. sp. albedinis 199 8.3.8 Canola–Leptosphaeria maculans 199 8.3.9 Saskatoons–Entomosporium mespili 200 8.4 Pathogens counter-defense against plants’ phenolic-related defenses 200 8.4.1 Phytophthora infestans 201 8.4.2 Verticillium dahliae 201 8.5 Concluding remarks 202 Acknowledgments 203 References 203 9 Absorption and Metabolism of Dietary Chlorogenic Acids and Procyanidins 209 Gary Williamson and Angelique Stalmach 9.1 Introduction 209 9.2 Procyanidins 210 9.2.1 Gut lumen stability of procyanidins 211 9.2.2 Absorption of intact procyanidins from the small intestine 211 9.2.3 Mechanism of absorption across small intestine 212 9.2.4 Absorption from the colon after microbial metabolism 212 9.3 Chlorogenic acids and hydroxycinnamates 214 9.3.1 Transport of chlorogenic acids 214 9.3.2 Chlorogenic acid absorption in humans 215 9.3.3 Chlorogenic acid metabolism 217 References 218 10 Extra-Virgin Olive Oil—Healthful Properties of Its Phenolic Constituents 223 Francesco Visioli and Elena Bernardini 10.1 Introduction 223 10.2 Epidemiological studies 225 10.3 In vitro studies on olive oil’s phenolics 225 10.4 In vivo studies 228 10.5 Olive oil and cancer 231 10.6 Potential mechanisms of action of olive phenols—to be elucidated 232 10.7 Focus on hydroxytyrosol 233 10.8 Olive mill waste water as a source of olive phenols 236 10.9 Conclusions 240 Acknowledgments 244 References 244 11 Analysis and Characterisation of Flavonoid Phase II Metabolites 249 Celestino Santos-Buelga, Susana González-Manzano, Montserrat Dueñas and Ana M. González-Paramás 11.1 Introduction 249 11.2 Flavonoid metabolism 251 11.3 Preparation of metabolites 253 11.3.1 Isolation from plant sources 254 11.3.2 Enzymatic synthesis of metabolites 254 11.3.3 Chemical synthesis 255 11.3.4 Purification of metabolites 257 11.4 Characterisation of flavonoid metabolites 258 11.4.1 UV spectra 258 11.4.2 Nuclear magnetic resonance 260 11.4.3 Mass spectrometry 261 11.5 Extraction and preparation 263 11.5.1 Sample preparation and storage 264 11.5.2 Hydrolysis 265 11.5.3 Solvent extraction 266 11.5.4 Solid phase extraction 267 11.6 Analysis of metabolites in biological samples 268 11.6.1 Quantification of total polyphenol metabolites 269 11.6.2 Analysis of individual metabolites 270 11.6.3 High performance liquid chromatography 270 11.6.4 Detection systems 272 11.6.5 Trends in the chromatographic analysis of flavonoid metabolites 276 Acknowledgments 277 References 277 12 High-speed Countercurrent Chromatography in the Separation of Polyphenols 287 Andrew Marston 12.1 Foreword 287 12.2 High-speed countercurrent chromatography 288 12.3 Separations of polyphenols 291 12.3.1 Preparative applications 291 12.3.1.1 Stilbene glycosides 291 12.3.1.2 Flavonolignans 293 12.3.1.3 Flavonoids 295 12.3.1.4 Anthocyanins 296 12.3.1.5 Proanthocyanidins and tannins 297 12.3.2 Analytical applications 301 12.4 Extensions of the basic countercurrent chromatography method 302 12.4.1 Reversed-phase operation 302 12.4.2 Multiple dual-mode operation 303 12.4.3 Elution–extrusion 303 12.4.4 Gradient elution 304 12.4.5 Hsccc/ms 305 12.4.6 Complexation HSCCC 306 12.4.7 High-performance ccc 307 References 307 13 Strategies for the Controlled Synthesis of Oligomeric Polyphenols 311 Scott A. Snyder 13.1 Introduction 311 13.2 Serial oligomer families 313 13.2.1 Overview 313 13.2.2 Catechin-derived oligomers 313 13.2.3 Ellagitannin-derived oligomers 316 13.3 Oligomer families with diverse bond connections 319 13.3.1 Overview 319 13.3.2 The resveratrol family of oligomeric natural products 320 13.3.2.1 Introduction 320 13.3.2.2 Biomimetic approaches 321 13.3.2.3 Stepwise synthesis approaches 330 13.3.3 Rosmarinic-acid-derived oligomers 337 13.4 Conclusion 345 Acknowledgments 345 References 346 Index 353