Recent Advances in Polyphenol Research

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 the scholarly society Groupe Polyphénols, this publication, which is the fourth volume in this highly regarded Recent Advances in Polyphenol Research series, is edited by Annalisa Romani, Vincenzo Lattanzio, and Stéphane Quideau. They have once again, like their predecessors, put together an impressive collection of cutting-edge chapters written by expert scientists, internationally respected in their respective field of polyphenol sciences. This Volume 4 highlights some of the latest information and opinion on the following major research topics about polyphenols:

• Biosynthesis and genetic manipulation

• Ecological role of polyphenols in plant defense

• Actions of polyphenols in human health protection

• Physical organic chemistry and organic synthesis

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.

Autorentext

Annalisa Romani, board member of the " Groupe
Polyphénols " (2008-2014), is Professor of Food Sciences
and Technologies at the University of Florence, Italy. Her research
laboratory is specialized in analytical, structural determination
and biological activities of plant polyphenols, with a recent focus
on food supplement and innovative extraction green technologies for
the recovery of purified molecules as bio-phenols.

Vincenzo Lattanzio, former President of the " Groupe
Polyphénols " (2004-2008), is full Professor of Plant
Biochemistry and Physiology at the University of Foggia (Italy).
His research interest concerns studies of the role of phenolic
compounds in resistance mechanisms of plant tissues against biotic
and abiotic stresses, with a recent focus on trade-off mechanism
between growth rate and adaptive response of plant tissues under
nutritional stress.

Stéphane Quideau, former President of the Groupe
Polyphénols (2008-2012), is full Professor of Organic and
Bioorganic Chemistry at the University of Bordeaux, France. His
research laboratory is specialized in plant polyphenol chemistry
and chemical biology, with a focus on the studies of ellagitannin
chemical reactivity and synthesis, and interactions of bioactive
polyphenols with their protein targets.

Inhalt

Acknowledgments vii

Contributors xvii

Preface xix

**1 Monolignol Biosynthesis and its Genetic Manipulation: The Good, the Bad, and the Ugly 1
**Richard A. Dixon, M.S. Srinivasa Reddy, and Lina Gallego-Giraldo

1.1 Introduction 2

1.2 Function and distribution of lignin in plants 2

1.3 Targets for modification of lignin biosynthesis 5

1.3.1 Gene targets 1. Biosynthetic enzymes 5

1.3.1.1 L-phenylalanine ammonia-lyase (PAL) 6

1.3.1.2 Cinnamate 4-hydroxylase (C4H) 6

1.3.1.3 4-coumarate: coenzyme-A ligase (4CL) 6

1.3.1.4 Enzymes of the coumaroyl shikimate shunt 7

1.3.1.5 Caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) 7

1.3.1.6 Ferulate 5-hydroxylase (F5H) 8

1.3.1.7 Caffeic acid 3-O-methyltransferase (COMT) 8

1.3.1.8 Cinnamoyl-CoA reductase 8

1.3.1.9 Cinnamyl alcohol dehydrogenase (CAD) 9

1.3.2 Gene targets 2. Transcription factors 9

1.4 Impacts of lignin modification through targeting of the monolignol biosynthetic pathway 9

1.4.1 L-phenylalanine ammonia-lyase (PAL) 10

1.4.2 Cinnamate 4-hydroxylase (C4H) 10

1.4.3 4-coumarate: coenzyme-A ligase (4CL) 11

1.4.4 Hydroxycinnamoyl-CoA: shikimate hydroxycinnamoyl transferase (HCT) 13

1.4.5 4-coumaroyl shikimate 3-hydroxylase (C3H) 14

1.4.6 Caffeoyl CoA 3-O-methyltransferase (CCoAOMT) 15

1.4.7 Ferulate 5-hydroxylase (F5H) 17

1.4.8 Caffeic acid O-methyltransferase (COMT) 18

1.4.9 Cinnamoyl-CoA reductase (CCR) 20

1.4.10 Cinnamyl alcohol dehydrogenase (CAD) 22

1.5 Impacts of lignin modification through targeting of TFs 23

1.5.1 NAC master switches 24

1.5.2 MYB repressors of monolignol biosynthesis 24

1.5.3 WRKY repressors of lignification in pith 24

1.6 Monolignol pathway modification and plant growth 25

1.7 Conclusions: it isn't all that bad! 26

References 27

**2 Perturbing Lignin Biosynthesis: Metabolic Changes in Response to Manipulation of the Phenylpropanoid Pathway 39
**Nickolas A. Anderson and Clint Chapple

2.1 Introduction 40

2.1.1 Cell wall-bound phenylpropanoids 40

2.1.2 Soluble phenylpropanoids 43

2.2 Changes in metabolism associated with phenylpropanoid-pathway disruptions 44

2.2.1 Phenylalanine ammonia-lyase (PAL) 44

2.2.2 Cinnamate 4-hydroxylase (C4H) 45

2.2.3 4-coumarate: CoA ligase (4CL) 46

2.2.4 Hydroxycinnamoyl-coenzyme A: shikimate/quinate hydroxycinnamoyltransferase (HCT)/p-coumaroyl shikimate 3-hydroxylase (C3H) 46

2.2.5 Cinnamoyl CoA reductase (CCR) 47

2.2.6 Ferulate 5-hydroxylase (F5H) 48

2.2.7 Caffeic acid/5-hydroxyferulic acid O-methyltransferase (COMT)/caffeoyl CoA 3-O-methyltransferase (CCoAOMT) 49

2.2.8 Cinnamyl alcohol dehydrogenases (CAD) 50

2.3 Atypical lignins 50

2.4 Dwarfism 51

2.5 Conclusions 52

References 52

**3 Function, Structure, and Evolution of Flavonoid Glycosyltransferases in Plants 61
**Keiko Yonekura-Sakakibara and Kazuki Saito

3.1 Introduction 61

3.2 UDP-dependent glycosyltransferases 63

3.2.1 Functional identification of flavonoid UGTs 63

3.2.1.1 Flavonoid 3-O-glycosyltransferases 63

3.2.1.2 Flavonoid 7-O-glycosyltransferases 63

3.2.1.3 Flavonoid glycosyltransferases that glycosylate the sugar moiety attached to a flavonoid aglycone 67

3.2.1.4 Flavonoid 3-O-glycosyltransferase 69

3.2.1.5 Flavonoid C-glycosyltransferase 69

3.2.2 3D structures of flavonoid UGTs 70

3.2.3 Functional evolution in UGTs 72

3.2.3.1 Functional evolution in flavonoid UGTs 74

3.3 Glycoside hydrolase-type glycosyltransferases 75

3.3.1 Functional identification of flavonoid GH1-type glycosyltransferases 75

3.3.1.1 Anthocyanin 5/7-O-glycosyltransferases 75

3.3.1.2 Anthocyanin 3-O-6-O-coumaroylglucoside: glucosyltransferase 76 <p&gt...