Dietary Polyphenols E-Book
218,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Serie: Institute of Food Technologists Series
- Sprache: Englisch
Presents recent research on metabolism and the health effects of polyphenols Consumer interest in the health benefits of many phenolic compounds found in plant foods and derivatives has grown considerably in recent years, giving rise to an increased demand for functional foods. Although preclinical and observational studies have promoted the protective properties of polyphenols for a range of chronic diseases, evidence has shown that most dietary polyphenols have little bioavailability. Once ingested, most of them are metabolized by either the intestinal enzymes or by the gut microbiota and then undergo extensive phase-II metabolism reaching significant concentrations of conjugated metabolites. They remain in the systemic circulation and target systemic tissues where trigger biological effects. The polyphenol-derived metabolites produced in humans are dependent upon the composition of the gut microbiota and the subject genetics. Thus all the metabolites do not show the same biological activity in different individuals. To fully understand the health effects of polyphenols, further clinical investigations are required. Dietary Polyphenols describes the latest findings on the polyphenol metabolism and reviews the current evidence on their health effects and that of their bioavailable metabolites. Emphasizing the importance of interindividual variability and the critical role of gut microbiota, this authoritative volume features contributions from recognized experts in the field, exploring specific families of extractable and non-extractable phenolic compounds that exhibit potential health effects. Topics include structural diversity of polyphenols and distribution in foods, bioavailability and bioaccessibility of phenolics, metabolism, and gastrointestinal absorption of various metabolites and their health effects. This comprehensive volume: * Discusses the bioavailability, bioaccessibility, pharmacokinetics studies, and microbial metabolism of different groups of phenolic compounds * Examines the interaction between polyphenols and gut microbiota * Describes analytical methods for identifying and quantifying polyphenols in foods and biological samples * Reviews recent epidemiological and clinical intervention studies showing protective effects of polyphenols Dietary Polyphenols: Metabolism and Health Effects is an important resource for scientists working in the area of dietary polyphenols and health effects, microbiota, and their interaction with other nutritional compounds, and for health professionals, nutritionists, dieticians, and clinical researchers with interest in the role of polyphenols in the prevention and treatment of chronic diseases.
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 818
Veröffentlichungsjahr: 2020
Ähnliche
Table of Contents
Cover
Dietary Polyphenols
Copyright
Titles in the IFT Press series
List of Contributors
1 Structural Diversity of Polyphenols and Distribution in Foods
1.1 Introduction
1.2 Classification and Chemistry of Polyphenols
1.3 Dietary Intake and Food Sources of Polyphenols
1.4 Databases Used to Assess Dietary Exposure to Polyphenols
1.5 Bioavailability, Metabolism, and Bioactivity of Dietary Polyphenols
Acknowledgments
References
2 Nonextractable Polyphenols: A Relevant Group with Health Effects
2.1 Introduction: The Concept of Nonextractable Polyphenols (NEPP)
2.2 Contribution of NEPP to Total Polyphenol Content and Intake
2.3 Metabolic Fate of NEPP: A Key Process for Their Health Effects
2.4 How NEPP may Exhibit Health Effects
2.5 Studies on the Health Effects of NEPP
2.6 Perspectives
References
3 Analytical Strategies for Determining Polyphenols in Foods and Biological Samples
3.1 Introduction: Importance of the Determination of Polyphenols
3.2 Most Widely Used Extraction Systems and New Trends
3.3 Determination of the Phenolic Compounds in Foods
3.4 Some Considerations Regarding the Determination of Polyphenols in Biological Samples
3.5 Conclusions and Future Directions
Acknowledgments
References
4 Hydroxycinnamates
4.1 Introduction
4.2 Metabolism of Hydroxycinnamates and Metabolic Pathways
4.3 Bioaccessibility and Bioavailability of Hydroxycinnamates: Influence of Food Matrix, Processing, Dose, and Interindividual Differences
4.4 Biological Activity of Hydroxycinnamates and Their Derivatives
References
5 Flavonols and Flavones
5.1 Introduction
5.2 Uptake and Metabolism of Flavonols and Flavones
5.3 Microbiota Formation of Low Molecular Weight Phenolic, Common Colonic Metabolites
5.4 Health Effects of Flavonol and Flavone Metabolites
5.5 Conclusions and Future Perspectives
Acknowledgments
References
6 Isoflavones
6.1 Uptake and Metabolism of Isoflavones
6.2 Biological Mechanisms of Isoflavones
6.3 Physiological and Health Effects of Isoflavones
6.4 Physiological and Health Effects of Isoflavone Metabolites and Metabotypes
6.5 Summary of Isoflavone Intake and Health
References
7 Dietary Anthocyanins
7.1 Absorption and Metabolism of Anthocyanins
7.2 Pharmacokinetics of Anthocyanins
7.3 Factors Affecting Anthocyanin Bioavailability
7.4 Biological Activity of Anthocyanin Metabolites
7.5 Conclusion
References
8 Flavan‐3‐ols: Catechins and Proanthocyanidins
8.1 Introduction: Chemistry and Main Dietary Sources
8.2 Bioavailability of Flavan‐3‐ols
8.3 Health Benefits of Flavan‐3‐ols and Their Derived Circulating Metabolites
8.4 Conclusions and Future Perspectives
References
9 Ellagitannins and Their Gut Microbiota‐Derived Metabolites: Urolithins
9.1 Chemistry and Sources of Ellagitannins and Ellagic Acid
9.2 Bioavailability of Ellagitannins and Ellagic Acid
9.3 The Microbial Metabolism of Ellagitannins and Ellagic Acid: Urolithins
9.4 Significance of Ellagitannins, Ellagic Acid, and Urolithins for Human Health
9.5 Conclusion
Acknowledgments
References
10 Lignans
10.1 Introduction
10.2 Lignans in Foods
10.3 Metabolism of Lignans
10.4 Blood Levels of Lignans after Dietary Intervention
10.5 Bioactivity of Plant Lignans and Enterolignans
10.6 Conclusions and Future Perspectives
Acknowledgments
References
11 Stilbenes: Beneficial Effects of Resveratrol Metabolites in Obesity, Dyslipidemia, Insulin Resistance, and Inflammation
11.1 Introduction: Occurrence and Intake
11.2 Absorption, Metabolism, and Excretion of Resveratrol
11.3 Biological Effects of Resveratrol Metabolites
11.4 Conclusion
Acknowledgments
References
12 Flavanones
12.1 Introduction
12.2 Flavanones and Their Occurrence
12.3 Absorption of Flavanone Metabolites in the Proximal and Distal Gastrointestinal Tract
12.4 Formation of 3‐(3′‐Hydroxy‐4′‐ Methoxyphenyl)Hydracrylic Acid
12.5 Factors Affecting the Bioavailability of Flavanones
12.6 Analysis of Flavanone Metabolites and Catabolites
12.7 Biomarkers and Metabolomics
12.8 Protective Effects
References
13 Understanding Polyphenols' Health Effects Through the Gut Microbiota
13.1 Microbial Metabolism of Dietary Polyphenols
13.2 Bacteria Responsible for Dietary Polyphenols Transformations and Health Implications
13.3 Modulation of Gut Microbiota by Dietary Polyphenols
Acknowledgments
References
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Main flavonoid groups and distribution in foods
Table 1.2 Nonflavonoid (poly)phenols and main dietary sources
Chapter 2
Table 2.1 Strategies for obtaining extractable and nonextractable polyphenols
Table 2.2 Contribution of EPP and NEPP to total polyphenol intake in the Span...
Table 2.3 Summary of biological activities reported for phenolic microbial me...
Chapter 3
Table 3.1 UV absorption maxima of the different phenolic categories
Table 3.2 Selected examples of determination of polyphenols in widely studied...
Table 3.3 Some illustrative examples of polyphenol determination in biologica...
Chapter 4
Table 4.1 Brief summary of the metabolism of hydroxycinnamic acids according ...
Chapter 5
Table 5.1 Hydroxylation pattern of kaempferol, quercetin, myricetin, apigenin...
Chapter 6
Table 6.1 Daidzein and
O‐
desmethylangolensin (ODMA) exposure patterns ba...
Chapter 7
Table 7.1 Concentration of major methylated and glucuronidated anthocyanin de...
Table 7.2 Gut microbiota modulation and gut microbiota‐mediated health benefi...
Chapter 8
Table 8.1 Examples of dietary sources of flavan‐3‐ols and content of their ma...
Chapter 9
Table 9.1 Representative ellagitannins present in some food products
Table 9.2 Main spectroscopic characteristics of the available urolithins (Gar...
Chapter 10
Table 10.1 Lignan content (μg/100 g as is basis) of selected foods
Table 10.2 Total and free plant lignans (μg/100 g dry matter) in wheat and ry...
Table 10.3 Influence of intake of plant lignans on plasma, urinary, and feces...
Table 10.4 Influence of diets varying in plant lignans on plasma and urine co...
Chapter 12
Table 12.1 Phenolic catabolites excreted in urine in significantly increased ...
Table 12.2 Intervolunteer variations in the urinary excretion of hesperetin a...
Table 12.3 List of flavanone metabolites and catabolites available from comme...
Chapter 13
Table 13.1 Hydrolysis of conjugated phenolics achieved by the human intestina...
Table 13.2 Enzymatic reactions of polyphenolic aglycones achieved by the huma...
List of Illustrations
Chapter 1
Figure 1.1 The basic structure of flavonoids.
Chapter 2
Figure 2.1 Contribution of nonextractable polyphenols to total polyphenol co...
Figure 2.2 Metabolic fate of nonextractable polyphenols (NEPP). HPP, hydroly...
Figure 2.3 Percentage of daily antioxidant capacity per capita intake in the...
Figure 2.4 Local and systemic effects of NEPP. HPP, hydrolyzable polyphenols...
Chapter 3
Figure 3.1 Schema representing the importance of having fully validated and ...
Figure 3.2 Different steps of a complete analytical procedure to achieve the...
Figure 3.3 Experimental schema for the analysis of phenolic compounds from f...
Chapter 4
Figure 4.1 Metabolic pathways of major hydroxycinnamates in the diet (CQAs, ...
Chapter 5
Figure 5.1 Structure of the 2‐phenyl‐chrome‐4‐one backbone common to all fla...
Figure 5.2 Plausible metabolic fate of quercetin, kaempferol, and myricetin ...
Figure 5.3 Plausible metabolic fate of apigenin and luteolin including bacte...
Figure 5.4 Pleiotropic action of flavonols (quercetin, myricetin, and kaempf...
Chapter 6
Figure 6.1 Chemical structures of daidzein and gut microbiota metabolites eq...
Chapter 7
Figure 7.1 Representation of the general structure of anthocyanins (flavyliu...
Figure 7.2 Anthocyanin equilibrium form at different pH.
Figure 7.3 Proposed mechanism for anthocyanin transport through MKN‐28 cell ...
Figure 7.4 Summary of the breakdown of flavonols, isoflavones, flavan‐3‐ols,...
Figure 7.5 Main phase II metabolites and microbial metabolites of monoglucos...
Chapter 8
Figure 8.1 Stereoisomers of monomeric flavan‐3‐ols with different patterns o...
Figure 8.2 Dimeric type B and type A proanthocyanidins.
Figure 8.3 Primary green and black tea flavan‐3‐ol derivatives.
Figure 8.4 Structures of leading native and colonic flavan‐3‐ol metabolites....
Figure 8.5 Exemplified catabolism of procyanidin B2 and (−)‐epicatechin by g...
Chapter 9
Figure 9.1 Representative dietary ellagitannins: pedunculagin (a), punicalin...
Figure 9.2 Main catabolic pathway from EA to urolithins.
Figure 9.3 Representative HPLC‐UV chromatogram at 305 nm of urolithins (a) a...
Chapter 10
Figure 10.1 Molecular structure of the main plant lignans in cereals.
Figure 10.2 Total free plant lignans (PL‐total), free syringaresinol (Syr) a...
Figure 10.3 Proposed metabolism of plant lignans and enterolignans (
red circ
...
Figure 10.4 Postprandial absorption/elimination curves of (a) Ses, (b) Pin, ...
Figure 10.5 Serum concentrations (mean ± SEM) of secoisolariciresinol, enter...
Figure 10.6 Portal and arterial plant lignan plasma concentrations after con...
Figure 10.7 Plasma concentrations of (A) PL
Total
, (B) Syr, and (C) PL
Other
c...
Figure 10.8 Conversion of plant lignans to enterolignans by human intestinal...
Figure 10.9 Portal (
closed circle
) and arterial (
closed triangle
) blood conc...
Figure 10.10 Fasting portal and arterial enterolignan plasma concentrations ...
Figure 10.11 Schematic presentation of the mechanisms behind the antiinflamm...
Chapter 11
Figure 11.1 Chemical structure of resveratrol and its main metabolites.
Figure 11.2 Summary of the effects of resveratrol metabolites (resveratrol‐3...
Figure 11.3 Summary of the effects of resveratrol metabolites ((resveratrol‐...
Figure 11.4 Antiinflammatory effects of resveratrol metabolites in human mac...
Figure 11.5 Antiinflammatory effects of resveratrol metabolites in human mac...
Figure 11.6 Hepatic bile acid and cholesterol metabolism. ABCG5, ATP‐binding...
Chapter 12
Figure 12.1 Proposed pathways for the metabolism of naringenin and ferulic a...
Figure 12.2 Proposed pathways for the colonic metabolism of hesperetin relea...
Figure 12.3 Potential route for the conversion of hesperetin to 3‐(3′‐hydrox...
Figure 12.4 Correlation between tested concentration of standards of hespere...
Chapter 13
Figure 13.1 Potential heterocyclic
C‐
ring cleavage of flavonoids by th...
Figure 13.2 Gut microbiota metabolites of some dietary flavonoid phenolics....
Figure 13.3 Dietary nonflavonoid phenolics that are metabolized by the gut m...
Figure 13.4 Microbial conversion of ellagic acid and urolithins produced by ...
Figure 13.5 Gut microbiota metabolites of some dietary nonflavonoid phenolic...
Guide
Cover
Table of Contents
Begin Reading
Pages
ii
iii
iv
6
xv
xvi
xvii
xviii
xix
xx
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
533
534
535
536
537
538
539
540
541
The IFT Press series reflects the mission of the Institute of Food Technologists—to advance the science of food contributing to healthier people everywhere. Developed in partnership with Wiley‐Blackwell, IFT Press books serve as leading‐edge handbooks for industrial application and reference and as essential texts for academic programs. Crafted through rigorous peer review and meticulous research, IFT Press publications represent the latest, most significant resources available to food scientists and related agriculture professionals worldwide. Founded in 1939, the Institute of Food Technologists is a nonprofit scientific society with 22 000 individual members working in food science, food technology, and related professions in industry, academia, and government. IFT serves as a conduit for multidisciplinary science thought leadership, championing the use of sound science across the food value chain through knowledge sharing, education, and advocacy.
IFT Press Advisory Group
Casimir C. Akoh
Christopher J. Doona
Florence Feeherry
Jung Hoon Han
David McDade
Ruth M. Patrick
Syed S.H. Rizvi
Fereidoon Shahidi
Christopher H. Sommers
Yael Vodovotz
Karen Nachay
IFT Press Editorial Board
Malcolm C. Bourne
Dietrich Knorr
Theodore P. Labuza
Thomas J. Montville
S. Suzanne Nielsen
Martin R. Okos
Michael W. Pariza
Barbara J. Petersen
David S. Reid
Sam Saguy
Herbert Stone
Kenneth R. Swartzel
Dietary Polyphenols
Metabolism and Health Effects
Edited by
Francisco A. Tomás‐BarberánDepartment of Food Science and TechnologyCEBAS‐CSIC, Murcia, Spain
Antonio González‐SarríasDepartment of Food Science and TechnologyCEBAS‐CSIC, Murcia, Spain
Rocío García‐VillalbaDepartment of Food Science and TechnologyCEBAS‐CSIC, Murcia, Spain
This edition first published 2021
© 2021 John Wiley & Sons, Inc.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.
The right of Francisco A. Tomás‐Barberán, Antonio González‐Sarrías, and Rocío García‐Villalba to be identified as the authors of the editorial material in this work has been asserted in accordance with law.
Registered Office
John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA
Editorial Office
The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK
For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.
Wiley also publishes its books in a variety of electronic formats and by print‐on‐demand. Some content that appears in standard print versions of this book may not be available in other formats.
Limit of Liability/Disclaimer of Warranty
While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.
Library of Congress Cataloging‐in‐Publication Data
Names: Tomás‐Barberán, F. A. (Francisco A.), editor. | González‐Sarrías,
Antonio, editor. | García‐Villalba, Rocío, editor.
Title: Dietary polyphenols : metabolism and health effects / edited
by Francisco A. Tomás‐Barberán, Antonio González‐Sarrías, Rocío
García‐Villalba.
Other titles: IFT press series.
Description: Hoboken, NJ : Wiley‐Blackwell, 2021. | Series: IFT press
series | Includes bibliographical references and index.
Identifiers: LCCN 2020019599 (print) | LCCN 2020019600 (ebook) | ISBN
9781119563723 (cloth) | ISBN 9781119563716 (adobe pdf) | ISBN
9781119563747 (epub)
Subjects: MESH: Polyphenols–metabolism | Polyphenols–pharmacology |
Nutritive Value
Classification: LCC QK898.P764 (print) | LCC QK898.P764 (ebook) | NLM QV
223 | DDC 613.2/86–dc23
LC record available at https://lccn.loc.gov/2020019599
LC ebook record available at https://lccn.loc.gov/2020019600
Cover Design: Wiley
Cover Images: Pomegranate © October 22 / Getty Images, Chemical bonding structures courtesy of Francisco A. Tomás‐Barberán, Human figure © Christos Georghiou / Shutterstock
Titles in the IFT Press series
Accelerating New Food Product Design and Development, 2
nd
Edition (Jacqueline H. Beckley, Leslie J. Herzog, M. Michele Foley)
Anti‐Ageing Nutrients: Evidence‐Based Prevention of Age‐Associated Diseases (Deliminda Neves)
Bioactive Compounds from Marine Foods: Plants and Animal Sources (Blanca Hernandez‐Ledesma, and Miguel Herrero)
Biofilms in the Food Environment, 2
nd
Edition (Anthont L. Pometto III, and Ali Demirci)
Bitterness: Perception, Chemistry and Food Processing (Michel Aliani, and Michael N.A. Eskin)
Essential Oils in Food Processing: Chemistry, Safery and Applications (Seyed Mohammed Bagher Hashemi, Amin Mousavi Khaneghah, and Anderson de Souza Sant'Ana)
Flavor, Satiety and Food Intake (Beverly Tepper, and Martin Yeomans)
Food Carotenoids: Chemistry, Biology and Technology (Delia B. Rodriguez‐Amaya)
Food Oligosaccharides: Production, Analysis and Bioactivity (F. Javier Moreno, and Maria Luz Sanz)
Food Safety Design, Technology and Innovation (Helmut Traitler, Birgit Coleman, and Karen Hofmann)
Food Texture Design and Optimization (Yadunandan Lal Dar, Joseph M. Light)
Functional Foods and Beverages: In vitro Assessment of Nutritional, Sensory, and Safety Properties (Nicolas Bordenave, and Mario G. Ferruzzi)
Mathematical and Statistical Methods in Food Science and Technology (Daniel Granato, and Gaston Ares)
Membrane Processing for Dairy Ingredient Separation (Kang Hu, and James Dickson)
Microbial Safety of Fresh Produce (Xuetong Fan, Brendan A. Niemira, Christopher J. Doona, Florence E. Feeherry, and Robert B. Gravani)
Microbiology and Technology of Fermented Foods, 2
nd
Edition (Robert W. Hutkins)
Microbiology in Dairy Processing: Challenges and Opportunities (Palmiro Poltronieri)
Nanotechnology and Functional Foods: Effective Delivery of Bioactive Ingredients (Cristina Sabilov, Hongda Chen, and Rickey Yada)
Natural Food Flavors and Colorants, 2
nd
Edition (Mathew Attokaran)
Packaging for Nonthermal Processing of Food, 2
nd
Edition (Melvin A. Pascall, and Jung H. Han)
Processing and Nutrition of Fats and Oils (Ernesto M. Hernandez, and Afaf Kamal‐Eldin)
Resistant Starch: Sources, Applications and Health Benefits (Yong‐Cheng Shi, Clodualdo C. Maningat)
Spray Drying Techniques for Food Ingredient Encapsulation (C. Anandharamakrishnan, and Padma Ishwarya S.)
Trait‐Modified Oils in Foods (Frank T. Orthoefer, and Gary R. List)
Water Activity in Foods: Fundamentals and Applications, 2
nd
Edition (Gustavo V. Barbosa‐Ćanovas, Anthony J. Fontana Jr., Shelly J. Schmidt, and Theodore P. Labuza)
List of Contributors
Aadil Bajoub
Department of Basic Sciences, National School of Agriculture, km 10, Haj Kaddour Road, B.P. S/40, Meknès, Morocco.
Adrian Cortés‐Martin
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain.
Alan Crozier
Department of Chemistry, King Saud University, Riyadh, Saudi Arabia.
and
School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, UK. Email:
Alba Macià
Departament de Tecnologia dels Aliments‐Àrea Nutrició, Universitat de Lleida, Lleida, Spain.
Alegría Carrasco‐Pancorbo
Department of Analytical Chemistry, Faculty of Science, University of Granada, Ave. Fuentenueva s/n, 18071, Granada, Spain. Email:
Alexandre Foito
The James Hutton Institute, Invergowrie, Dundee, Scotland UK.
Alfredo Fernández‐Quintela
Nutrition and Obesity group, Department of Nutrition and Food Sciences, Faculty of Pharmacy, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Centre, Vitoria, Spain.
and
CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Institute of Health Carlos III, Spain.
Ana Faria
Nutrition and Metabolism, Faculdade de Ciências Médicas|NOVA Medical Schoo|, Universidade NOVA de Lisboa, Lisboa, Portugal.
and
CINTESIS, Center for Health Technology Services Research, Porto, Portugal.
and
Comprehensive Health Research Centre, Universidade NOVA de Lisboa, Lisboa, Portugal.
Anne K. Bolvig
Aarhus University, Department of Animal Science, DK‐8830 Tjele, Denmark
Antonio González‐Sarrías
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain. Email: [email protected]
Cara L. Frankenfeld
Department of Global and Community Health, George Mason University, Fairfax, VA, USA. Email:
Claudia Favari
Human Nutrition Unit, Department of Food & Drug, University of Parma, Parma, Italy.
Cláudia Marques
Nutrition and Metabolism, Faculdade de Ciências Médicas|NOVA Medical Schoo|, Universidade NOVA de Lisboa, Lisboa, Portugal.
and
CINTESIS, Center for Health Technology Services Research, Porto, Portugal.
Claudia Nunes dos Santos
CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal. Email:
Claudio Curti
Department of Food & Drug, University of Parma, Parma, Italy.
Colin D. Kay
Food Bioprocessing and Nutritional Sciences, Plants for Human Health Institute, North Carolina State University, Kannapolis, North Carolina, USA.
Conceição Calhau
Nutrição e Metabolismo, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.
and
CINTESIS ‐ Center for Research in Health Technologies and Information Systems, Porto, Portugal.
Daniele Del Rio
Human Nutrition Unit, Department of Veterinary Science, University of Parma, Parma, Italy.
Derek Stewart
The James Hutton Institute, Invergowrie, Dundee, Scotland UK.
and
School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, Scotland.
Diogo Carregosa
CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal.
Donato Angelino
Human Nutrition Unit, Department of Veterinary Science, University of Parma, Parma, Italy.
Francisco A. Tomás‐Barberán
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain. Email: [email protected]
Gema Pereira‐Caro
Department of Food Science and Health, Andalusian Institute of Agricultural and Fishery Research and Training, Alameda del Obispo, Córdoba, Spain.
Gordon McDougall
The James Hutton Institute, Invergowrie, Dundee, Scotland UK.
Hélder Oliveira
REQUIMTE/LAQV, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.
Helle Nygaard Lærke
Aarhus University, Department of Animal Science, DK‐8830 Tjele, Denmark
Iñaki Milton‐Laskibar
Nutrition and Obesity group, Department of Nutrition and Food Sciences, Faculty of Pharmacy, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Centre, Vitoria, Spain.
and
CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Institute of Health Carlos III, Spain.
Itziar Eseberri
Nutrition and Obesity group, Department of Nutrition and Food Sciences, Faculty of Pharmacy, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Centre, Vitoria, Spain.
and
CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Institute of Health Carlos III, Spain.
Iva Fernandes
REQUIMTE/LAQV, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.
Iziar A. Ludwig
Departament de Tecnologia dels Aliments‐Àrea Nutrició, Universitat de Lleida, Lleida, Spain. Email:
Jara Pérez‐jiménez
Department of Metabolism and Nutrition, Institute of Food Science, Technology and Nutrition (ICTAN‐CSIC), José Antonio Novais 10, 28040, Madrid, Spain. Email:
Juan A. Giménez‐Bastida
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain.
Juan C. Espín
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain.
Katerina Valentova
Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic.
Knud E. Bach Knudsen
Aarhus University, Department of Animal Science, DK‐8830 Tjele, Denmark. Email:
Laura Rubió
Departament de Tecnologia dels Aliments‐Àrea Nutrició, Universitat de Lleida, Lleida, Spain.
Lucía Olmo‐García
Department of Analytical Chemistry, Faculty of Science, University of Granada, Ave. Fuentenueva s/n, 18071, Granada, Spain.
María A. Ávila‐Gálvez
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain.
Maria P. Portillo
Nutrition and Obesity group, Department of Nutrition and Food Sciences, Faculty of Pharmacy, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Centre, Vitoria, Spain.
CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Institute of Health Carlos III, Spain. Email:
Maria P. Romero
Departament de Tecnologia dels Aliments‐Àrea Nutrició, Universitat de Lleida, Lleida, Spain.
Maria Romo‐Vaquero
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain.
Maria V. Selma
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain. Email:
Mette Skou Hedemann
Aarhus University, Department of Animal Science, DK‐8830 Tjele, Denmark
Michael N. Clifford
School of Biosciences and Medicine, University of Surrey, Guildford, UK.
Natalja Nørskov
Aarhus University, Department of Animal Science, DK‐8830 Tjele, Denmark
Nuno Mateus
REQUIMTE/LAQV, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.
Pedro Mena
Human Nutrition Unit, Department of Food & Drug, University of Parma, Parma, Italy. Email:
Regina Menezes
CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal.
Rocío García‐Villalba
Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Dept. Food Science and Technology, CEBAS‐CSIC, Murcia, Spain. Email:
Romina P. Monasterio
Instituto de Biología Agrícola de Mendoza (IBAM), UNCuyo, CONICET. Alt. Brown 500, Chacras de Coria, Mendoza, Argentina.
Rosalía Reynoso‐Camacho
Research and Graduate Studies in Food Science, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las campanas s/n, 76010 Querétaro, Qro., México.
Saioa Gómez‐Zorita
Nutrition and Obesity group, Department of Nutrition and Food Sciences, Faculty of Pharmacy, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Centre, Vitoria, Spain.
and
CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Institute of Health Carlos III, Spain.
Victor de Freitas
REQUIMTE/LAQV, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal. Email:
Yuridia Martínez‐Meza
Research and Graduat Studies in Food Science, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las campanas s/n, 76010 Querétaro, Qro., México.
1Structural Diversity of Polyphenols and Distribution in Foods
Antonio González‐Sarrías*, Francisco A. Tomás‐Barberán, and Rocío García‐Villalba
Laboratory of Food and Health, Research Group on Quality, Safety, and Bioactivity of Plant Foods, Department Food Science and Technology, CEBAS‐CSIC, Murcia, Spain
1.1 Introduction
(Poly)Phenolic compounds or polyphenols are the most common and ubiquitous groups of secondary metabolites widely distributed in the Plant Kingdom. These metabolites are involved in important roles in plants, such as pigmentation, growth and reproduction functions, protection against ultraviolet (UV) radiation, resistance to pathogens and herbivores, and many other functions. They also contribute substantially to the organoleptic characteristics of flowers, leaves, fruits, and vegetables such as bitterness, astringency, color, and flavor (Bravo, 1998; Lattanzio et al., 2008; Pandey and Rizvi, 2009; Tomás‐Barberán and Espín, 2001). Apart from beneficial effects on plants, many of these nonnutrient metabolites have been attributed as the molecules potentially responsible for the health effects in humans. Vegetable‐ and fruit‐rich diets exhibit a wide spectrum of potential biological activities related to the prevention of many of the major chronic diseases such as cardiovascular, neurodegenerative, and cancer diseases (D'Archivio et al., 2007; Espín et al., 2017; Rothwell et al., 2017). In this book, the most recent studies about metabolism and the current evidence on the health effects of the different group of polyphenols, as well as their bioavailable metabolites, will be reviewed and discussed.
1.2 Classification and Chemistry of Polyphenols
The structure of phenolic compounds varies extensively but presents as a common feature the presence of one (simple phenolics) or more (polyphenols) hydroxyl substituents attached directly to one or more aromatic or benzene rings. Therefore, they have been classified into different groups or classes according to the pattern of their basic skeleton, from relatively simple, such as phenolic acids, to polymerized molecules of relatively high molecular mass, such as hydrolyzable and condensed tannins (Manach et al., 2004; Pereira et al., 2010). In general, the phenolic compounds are found in plants in the conjugated form rather than as free compounds, with one or more sugar residues linked by β‐glycosidic bonds to a hydroxyl group (O‐glycosides) or a carbon atom of the aromatic ring (C‐glycosides). The associated sugars can be monosaccharides, disaccharides or even oligosaccharides, glucose being the most common followed by others such as galactose, rhamnose, xylose, arabinose, etc. (Manach et al., 2004).
Moreover, the wide structural diversity in phenolic compounds encompasses over 8000 compounds described in nature that traditionally are divided into two main groups based on their basic structure, flavonoids and nonflavonoids, that are subdivided into different subgroups according to the number of aromatic or phenol rings and the structural elements that bind these rings to one another (Bravo, 1998; D'Archivio et al., 2007; Del Rio et al., 2013; Waterhouse, 2002).
1.2.1 Flavonoids
Flavonoids are the largest group of phenolic compounds, accounting for more than 5000 different compounds present in dietary plant foods, although they usually occur as glycosides rather than aglycones, mostly linked to glucose, rhamnose, xylose or galactose (Harbone and Williams, 2000; Tsao, 2010). The basic flavonoid structure is composed of two phenol rings (A and B) linked through a linear three‐carbon chain that forms a heterocyclic pyran ring (C) containing one oxygen atom (Figure 1.1).
Figure 1.1 The basic structure of flavonoids.
Based on the degree of oxidation, saturation, and hydroxylation of the central pyran ring, flavonoids can be divided into different subgroups as flavan‐3‐ols (catechins and proanthocyanidins), flavones, flavonols, flavanones, isoflavones, and anthocyanidins (Table 1.1) (Bravo, 1998). The diversity of each group of flavonoids depends on the different patterns of substitution of the hydroxyl groups in the basic flavonoid skeleton, mainly the conjugation with various mono‐ and disaccharides creating highly complex structures (Bravo, 1998). In addition to these major flavonoid groups, there are other minor ones such as chalcones, dihydrochalcones, dihydroflavonols, and flavan‐3,4‐diols. In Table 1.1, the most common examples of different flavonoid subgroups found in plant foods are listed.
Table 1.1 Main flavonoid groups and distribution in foods
Structure
Main compounds
Food sources
Catechin Epicatechin Epicatechin gallate Gallocatechin
Apple, apricot, peach, grape, berries, cereals, chocolate, red wine, nuts, black and green tea
Procyanidin B1 Procyanidin B2
Red wine, beer, cider, apple, pear, grape, chocolate
Apigenin Luteolin Chrysin
Parsley, celery, lettuce, artichoke, herbs (rosemary, thyme, oregano, etc.), citrus fruits, cereal grains, sweet peppers
Quercetin Kaempferol Myricetin Isorhamnetin
Yellow and red onion, caper, lettuce, parsley, berries, green and black tea, mango, carrot, pumpkin, kale, cabbage, broccoli, garlic
Naringenin Hesperetin
Orange, grapefruit, lemon, lime
Daidzein Genistein Glycitein
Soybean, tofu, green bean, lentil, chickpea, pea, mung bean, broad bean, medicinal herbs
Cyanidin Delphinidin Pelargonidin Peonidin
Berries, currant, grape, aronia, cherries, plum, pomegranate, red wine, red cabbage, eggplant, red onion, radish, hazelnut, pistachio nut, black and red bean, medicinal herbs
Flavan‐3‐ols or flavanols are structurally characterized by the presence of a hydroxyl group in the heterocyclic ring C. Unlike other flavonoid subgroups, they cannot occur as glycosides in food sources, but exist as simple monomers such as catechin and epicatechin, to the oligomeric and polymeric condensed tannins, which are also known as proanthocyanidins. Proanthocyanidins are highly complex chemical structures formed by oligomerization or polymerization of up to 50 subunits of monomeric flavanols joined by one (type B proanthocyanidins) or two (type A proanthocyanidins) oxidative couplings between two monomers. Proanthocyanidins containing only catechin/epicatechin units are known as procyanidins, which are the most common in nature, while those formed by gallocatechin/epigallocatechin units are called prodelphinidins, and those with afzelechin/epiafzelechin units are known as propelargonidins (Smeriglio et al., 2017; Spranger et al., 2008).
Flavones are structurally characterized by a double bond and an oxygen atom in the heterocyclic ring C of the flavonoid skeleton. Flavones, such as apigenin and luteolin, can be found in plants showing a wide range of substitutions, including methylations, hydroxylations, acylations, and glycosylations leading mainly to O‐ or C‐glycosides (Hostetler et al., 2017).
Flavonols contain a similar structure to flavones but with the presence of a hydroxyl group at carbon 3 of the flavone nucleus (3‐hydroxyflavones). Flavonols are one of the most abundant flavonoid subgroups widely found in plants; they are commonly found as glycosides and the most common one is quercetin (Leo and Woodman, 2015).
Flavanones and dihydroflavonols contain a similar structure to that of flavones and flavonols in which the double bond in the heterocyclic ring C has been reduced (hydrogenated). Flavanones are one of the main flavonoid subgroups and are mostly found in the form of glycosylated derivatives through the formation of an O‐glycosidic linkage usually with a rutinosyl (rhamnosyl 1‐6 glucosyl‐) or a neohesperidosyl (rhamnosyl 1‐2 glucosyl‐) moiety to the aglycone hydroxyl groups, the most common being glycosylation of the hydroxyl at C‐7 of ring A (Barreca et al., 2017).
Isoflavones or isoflavonoids differ from the other flavonoid subgroups because the ring B is bound to the heterocyclic ring C at C‐3 position instead of C‐2. Unlike other flavonoid subgroups, the occurrence of isoflavones in plants is limited, almost exclusively, to leguminous plants, mainly found in the form of β‐glucosides and their acetyl‐ or malonyl‐derivatives. However, there is a large structural variation of isoflavones according to the oxidation level of their skeleton. Isoflavones, like lignans, and stilbenes are also classified as phytoestrogens due to their structural similarities to estrogens and, therefore, their capacity to bind to estrogen receptors (Heinonen et al., 2002). The dietary glucosylated isoflavones, such as daidzin or genistin, are poorly absorbed after consumption. However, they are cleaved to their aglycones, daidzein and genistein, which are readily absorbed into the circulatory system and/or further metabolized in the colon by the action of the intestinal microbiota to other bioactive metabolites such as equol, O‐desmethylangolensin (ODMA), and dihydrogenistein (Frankenfeld et al., 2014; Heinonen et al., 2002; Zaheer and Humayoun Akhtar, 2017). Thus, it is well established that interindividual differences in the conversion of the isoflavone daidzein to equol and ODMA are associated with the heterogeneity of individual biological responsiveness to the consumption of isoflavones‐containing products (Frankenfeld et al., 2014; Heinonen et al., 2002).
Anthocyanidins are water‐soluble pigments responsible for the red, blue, and purple‐colored plant organs, mainly flowers, fruits, and leaves, depending on the light, pH, and temperature (Khoo et al., 2017; Laleh et al., 2006). They differ from other flavonoid subgroups because they have a positive charge at the oxygen atom of the heterocyclic ring C of the basic flavonoid structure, also called the flavylium (2‐phenylchromenylium) cation. They lead to a wide variety of pigments in plants and are commonly found as glycosides, called anthocyanins, which are bonded to various sugar residues mainly attached to the hydroxyl at C‐3 on the heterocyclic ring C or attached to the hydroxyl groups of the ring A at C‐5 and C‐7 position. Among monosaccharides, such as glucose, xylose or galactose, and disaccharides, such as rutinose or neohesperidose, glucose is the most common glycosyl unit found in anthocyanins. These sugar moieties can also be acylated with different aromatic (p‐coumaric, ferulic, caffeic, sinapic) or aliphatic acids (malonic, acetic) (D'Archivio et al., 2007; Khoo et al., 2017; Krga and Milenkovic, 2019; Wallace and Giusti, 2015).
1.2.2 Nonflavonoids
Nonflavonoids are the other principal group of phenolic compounds with dietary importance which generally have both a simpler chemical structure than that of the flavonoids as well as large and complex polyphenols. The main nonflavonoid phenolics include the simple phenolic acids (hydroxycinnamic and hydroxybenzoic acids), the hydrolyzable tannins (ellagitannins and gallotannins), stilbenes, coumarins, and lignans (Bravo, 1998). Table 1.2 shows the most common examples of nonflavonoid phenolics found in plant foods.
Table 1.2 Nonflavonoid (poly)phenols and main dietary sources
Structure
Main compounds
Food sources
p
‐Coumaric acid Caffeic acid Ferulic acid Sinapic acid
Coffee, potato, broccoli, spinach, lettuce, cabbage, apple, pear, cherries, apricot, peach, blackcurrant, blueberry, asparagus, wine, rye bread
Gallic acid Protocatechuic acid Syringic acid Vanillic acid
Cloudberry, raspberry, red cabbage, chestnut, tea
Sanguiin H6 Punicalagin Pedunculagin
Strawberry, raspberry, blackberry, pomegranate, walnut, chestnut, hazelnut, mango, green and black tea, oak‐aged beverages
Galloyl‐hexoside Digalloyl‐hexoside
Mango, chestnut, red sword bean
Resveratrol
Red wine, grape
Umbelliferona Esculetina Scoparone
Citrus, parsley, celery, medicinal herbs
Secoisolariciresinol Matairesinol Pinoresinol Lariciresinol
Flaxseed, sesame seeds
Phenolic acids are simple phenols that contain a carboxyl group and occur mainly as hydroxybenzoic (C6‐C1 skeleton) and hydroxycinnamic acids (C6‐C3 skeleton) which derive from benzoic or cinnamic acid, respectively. They can occur in plant foods either in their free or conjugated form attached to different functional groups or esterified to organic acids (Razzaghi‐Asl et al., 2013; Robbins, 2003).
The hydrolyzable tannins have a high molecular weight and are formed by a carbohydrate moiety, usually glucose, partially or totally esterified with phenolic residues such as gallic acid in the case of gallotannins or hexahydroxydiphenic acid (precursor of ellagic acid after hydrolysis) for ellagitannins. Unlike the flavonoid‐derived condensed tannins, they are readily hydrolyzed under acid hydrolysis (Okuda et al., 1995; Smeriglio et al., 2017; Tomás‐Barberán et al., 2008). It is well documented that ellagitannins and ellagic acid have limited bioavailability. Indeed, when ellagic acid, either released from ellagitannins or free ellagic acid occurring naturally in foods, reaches the distal part of the gastrointestinal tract, it is further hydrolyzed and/or metabolized by the colonizing microbiota into a family of dibenzo[b,d]pyran‐6‐one derivatives known as urolithins that can reach systemic tissues (Cerdá et al., 2004; Tomás‐Barberán et al., 2017). Urolithins are bioavailable microbial metabolites characterized by a nucleus of a dibenzo [b,d]pyran6‐one with different hydroxylation patterns. In recent years, three different ellagitannin‐metabolizing metabotypes have been described in humans associated with interindividual variability in urolithin production, which depends on gut microbiota composition (Tomás‐Barberán et al., 2014).
Stilbenes are structurally characterized by the presence of two phenyl moieties connected by a two‐carbon methylene bridge (C6‐C2‐C6). They can be found as both monomeric and oligomeric forms that are produced by oxidative coupling between monomeric stilbenes such as trans‐resveratrol (Rivière et al., 2012; Shen et al., 2009). Since there are more than 400 natural stilbenes in the plant kingdon, low quantities of stilbenes are present in the human diet, resveratrol being the most representative which occurs in both cis and trans isomers as well as in glycosylated forms such as its glucoside, piceid (D'Archivio et al., 2007; Del Rio et al., 2013; Shen et al., 2009).
Coumarins are a family of benzopyrones derived from hydroxycinnamic acids (C6‐C3) by lactonization. The most common are coumarins, isocoumarins, furanocoumarins, and benzocoumarins. They are highly bioactive, and even toxic, compounds that are seldom found in foods (Matos et al., 2015).
Finally, lignans are nonflavonoid phytoestrogens whose structure derives from oxidative dimerization of two phenylpropanoid units (C6‐C3) linked at the central carbon (C8‐C8′). Lignans are generally found in free forms, although to a lesser extent they can be coupled to sugars as glycosidic derivatives. It is well established that dietary lignans are metabolized by intestinal microbiota to the bioactive mammalian lignans or enterolignans, enterodiol and enterolactone, that contain a structure with only two phenolic hydroxyl groups, at the metaposition of each aromatic ring (D'Archivio et al., 2007; Raffaelli et al., 2002; Saleem et al., 2005).
1.3 Dietary Intake and Food Sources of Polyphenols
As indicated above, phenolic compounds or polyphenols are nonnutrient secondary metabolites widely spread throughout the plant kingdom as constituents of almost all vegetables, fruits, cereals, beverages such as tea, coffee, and red wine, and other plant‐derived foods, and therefore, they represent an important source of bioactive compounds in the human diet (Pérez‐Jiménez et al., 2010a; Scalbert and Williamson, 2000). Moreover, polyphenols are involved, both positively and negatively, in the sensory and organoleptic properties of fruits and vegetables such as color, flavor, and astringency (Ignat et al., 2011; Tomás‐Barberán and Espín, 2001).
According to several observational studies conducted in different cohorts, the estimated mean total daily intake of polyphenols can reach over 1 g, becoming the most abundant micronutrients present in a regular diet (Manach et al., 2004; Miranda et al., 2016; Ovaskainen et al., 2008; Pérez‐Jiménez et al., 2011; Pinto and Santos, 2017; Tresserra‐Rimbau et al., 2013; Zamora‐Ros et al., 2016). Over 500 different polyphenols are found in low or high amounts in most of the over 400 plant species regularly consumed in the human diet. One‐third of dietary polyphenols is dominated by phenolic acids and the remaining two‐thirds by the largest subgroup of flavonoids (Gupta et al., 2013; Pérez‐Jiménez et al., 2010b). It is well known that fruit and beverages such as tea, coffee, and red wine are the most relevant from their content in the diet, but vegetables, cereals, and leguminous plants are also important sources. However, their polyphenol content may significantly differ among different varieties of a specific plant food based on genotype and ecophysiological factors as well as environmental and agronomic conditions (high or low temperature, UV exposure, insect attack, postharvest handling, water supply) and food processing‐related factors (type of storage, culinary preparation, type of processing) (D'Archivio et al., 2007; Manach et al., 2004; Schreiner, 2005).
Most plant foods contain complex mixtures of polyphenols. Some of them, however, are mainly present in particular foods such as flavanones in citrus fruit, isoflavones in legumes (soybean and derived foods), dihydrochalcones (phloridzin) in apples, or flavones in celery and parsley. Other polyphenols, such as quercetin or catechin, are, however, found in many food products (fruit, vegetables, cereals, tea, wine). In Tables 1.1 and 1.2, the most common sources of each phenolic subgroup are presented.
1.3.1 Flavonoids
Flavonoids (see Table 1.1) are extensively found in most foodstuffs of plant origin but mainly in fruits such as apples, berries, and citrus fruits, vegetables such as onions and parsley, together with red wine, green and black tea, cocoa, nuts and certain spices (Beecher, 2003; Crozier et al., 2009; Manach et al., 2004; Marzocchella et al., 2011).
Regarding flavanols, mainly catechin and epicatechin, the main representative sources are fruits such as apples, apricots, peaches, grapes, and some berries, cereals, chocolate, red wine, and nuts, whereas flavanols such as epigallocatechin gallate, gallocatechin or epigallocatechin are found especially in Camellia sinensis teas (black, green, etc.) (Arts et al., 2000a,b; Manach et al., 2004). On the other hand, the most abundant type of proanthocyanidins found in plant foods is the dimeric procyanidins B1, B2, B3, and B4, that consist exclusively of epicatechin/catechin units. These procyanidins have been reported to be responsible for the astringent character of beverages (red wine, beer, and cider) and fruits (apples, pears, grapes, etc.) and the bitterness of chocolate (D'Archivio et al., 2007; Crozier et al., 2009; Gu et al., 2004; Rasmussen et al., 2005).
Flavones are the least common flavonoids in food. They occur in relatively high amounts in parsley and celery (apigenin and luteolin). They are also present as O‐glycosides and C‐glycosides in many different food products of the family Asteraceae (lettuce and artichoke) and Lamiaceae (herbs such as rosemary, thyme, oregano, mint, sage, etc.). They also occur in citrus fruits (vicenin‐2, orientin), and cereal grains, (tricetin, tricin, luteolin, and apigenin C‐ and di‐C‐glycosides) as well as in sweet peppers (D'Archivio et al., 2007; Del Rio et al., 2013; Hostetler et al., 2017). In addition, low amounts of methylated flavones such as diosmetin‐, acacetin‐, and chrysoeriol‐C‐glycosides are also found in citrus juices, mainly in mandarin orange, orange, citron, and bergamot juices, as well as low quantities of luteolin and apigenin in red and white wine (Del Rio et al., 2013; Hostetler et al., 2017). Finally, lesser amounts are found in other food sources such as blue fruits, pumpkin, chicory, kumquat, olive oil, honey, etc. as well as in some cereals and legumes such as wheat grain, black rice, fava bean, chickpea, etc. (Hostetler et al., 2017).
Flavonols constitute the most ubiquitous flavonoid subgroup in our diet, with quercetin as the most consumed type of flavonols, typically found as glycosides. The main food sources of quercetin are yellow and red onions, capers, lettuce, parsley, and some types of berries, and in lesser amounts also found in apples, figs, Brussels sprouts, and buckwheat (Bhagwat et al., 2011; D'Archivio et al., 2007; Del Rio et al., 2013). Other dietary flavonols also commonly found as O‐glycosides are kaempferol and myricetin, found in green and black tea as well as in fruits and vegetables such as mango, carrot or pumpkin, and Brassicaceae such as kale, cabbage, and broccoli or Alliaceae such as garlic (Crozier et al., 2009; Miean and Mohamed, 2001).
Flavanones are found in high concentrations mainly in citrus fruits and their juices (orange, grapefruit, lemon, lime, kumquat, etc.) where they account for approximately 95% of the flavonoids in the Citrus genus (Bhagwat et al., 2011; Peterson et al., 2006). They are also found in artichokes, tomatoes, and certain aromatic plants such as oregano (Bhagwat et al., 2011; Crozier et al., 2009; Ignat et al., 2011). The main flavanone glycosides (rhamnosyl‐glucosides) are hesperidin (hesperetin‐7‐O‐rutinoside) found in oranges, naringin (naringenin‐7‐O‐neohesperidoside) found in grapefruit, neohesperidin (hesperetin‐7‐O‐neohesperidoside) found in bitter oranges, and eriocitrin (eriodictyol‐7‐O‐rutinoside) found in lemons (D'Archivio et al., 2007; Peterson et al., 2006).
Isoflavones occur almost exclusively in legumes (Leguminosae), with the highest amount found in the cultivated soybean (Glycine max (L.)). Thus, soybean, also referred to as soy or soya, and its processed products including soy flour, soy flakes, miso, tempeh, natto, tofu, and soy milk, represent the main source of isoflavones (Danciu et al., 2018; D'Archivio et al., 2007; Zaheer and Humayoun Akhtar, 2017). The main isoflavones, referred to as phytoestrogens to indicate their estrogenic properties, are genistein, daidzein, and glycitein that occur as aglycones, mainly in processed soy products, or more often as glycosidic forms, mainly in grains, that are less well absorbed (Danciu et al., 2018; Mazur et al., 1998; Zaheer and Humayoun Akhtar, 2017). In addition to soybean, other legumes also contain significant amount of isoflavones such as green beans, lentils, chickpeas, peas, mung beans, and broad beans, as well as several medicinal plants including red clover, lucerne, and sohphlang flax (Danciu et al., 2018; Ko, 2014; Zaheer and Humayoun Akhtar, 2017).
Finally, anthocyanins represent one of the most important components of flavonoids in the human diet. Anthocyanins are widely distributed in vegetables and fruits and are responsible for the blue, purple, and red pigments found in flowers, fruits, leaves, and roots. They are also increasing being used as colorants for the food industry (D'Archivio et al., 2007; Khoo et al., 2017; Krga and Milenkovic, 2019). The most common types of anthocyanidins widespread in fruits and vegetables are cyanidin (responsible for reddish‐purple pigment), delphinidin (responsible for blue‐reddish or purple pigment), pelargonidin (responsible for red and orange pigment), peonidin (responsible for reddish‐purple pigment), malvidin (responsible for purple‐blue and red pigment), and petunidin (responsible for dark red or purple pigment) (Bąkowska‐Barczak, 2005; Katsumoto et al., 2007; Khoo et al., 2017). Among colored fruits, the main dietary sources are berries (elderberries, bilberries, blueberries, blackberries, strawberries, raspberries), currants, grapes, aronia, cherries, plums, pomegranates, some tropical fruits, and fruit‐derived products (red wine, fruit juices, and jams). Among dark‐colored vegetables and cereals, anthocyanins are found in red cabbage, eggplant, red onions, radishes, hazelnuts, pistachio nut, and black and red beans, as well as certain varieties of herbal medicinal plants including red clover, red hibiscus, and purple passion flower (Bhagwat et al., 2011; D'Archivio et al., 2007; Khoo et al., 2017).
1.3.2 Nonflavonoids
The nonflavonoid polyphenols group (see Table 1.2) is rich and diverse. It includes the phenolic acids, commonly found in many foods such as coffee and many types of fruits, the hydrolyzable tannins found in pomegranate, berries, nuts, tropical fruits, the stilbenes such as resveratrol found mostly in red wine, and the lignans found in flaxseed, sesame, and many grains and fruits (D'Archivio et al., 2007; Del Rio et al., 2013; Manach et al., 2004; Robbins, 2003).
Phenolic acids are abundant in the human diet, being present in all plant food groups. Phenolic acids can be distinguished in two main classes: cinnamic acid derivatives (hydroxycinnamic acids) and benzoic acid derivatives (hydroxybenzoic acids). Hydroxycinnamic acids such as p‐coumaric, caffeic, ferulic, and sinapic acids are more abundant in plant foods and are commonly found as glycosides, esters of glucose, and esters of quinic acid. They are rich in coffee and some vegetables, fruits, and cereals, particularly in potatoes, broccoli, spinach, lettuce, cabbage, apples, pears, cherries, apricots, peaches, blackcurrants, blueberries, asparagus, wine, and rye bread (Bravo, 1998; D'Archivio et al., 2007; Del Rio et al., 2013; El Gharras, 2009; Manach et al., 2004). Regarding hydroxybenzoic acids, in particular, gallic, protocatechuic, syringic and vanillic acids, they are found in very few edible plant foods, mainly in some berries such as cloudberry or raspberry, red cabbage, chestnut, and tea (D'Archivio et al., 2007; El Gharras, 2009; Manach et al., 2004). Hydroxybenzoic acids, such as gallic or hexahydroxydiphenic acids, are constituents of hydrolyzable tannins such as the gallotannins found in mango and the ellagitannins of various types of fruit, such as strawberries, raspberries, blackberries and pomegranate, and in nuts (Manach et al., 2004).
The hydrolyzable tannins are divided into two classes: those composed of ellagic and gallic acid esters of glucose or related sugars (ellagitannins and galotannins, respectively) (Okuda et al., 1995; Tomás‐Barberán et al., 2008). Ellagitannins such as sanguiin H6, punicalagin or pedunculagin are found in significant amounts in many berries, in particular strawberries and raspberries, as well as in other fruits and nuts such as pomegranate, muscadine grapes, walnuts, chestnuts, hazelnuts, mango, green and black tea, and are also present in oak‐aged beverages (wine, whiskey, etc.) (Crozier et al., 2009; Tomás‐Barberán et al., 2008, 2016). Gallotannins, unlike ellagitannins, are rarely found in plant foods, and occur almost exclusively in mango, chestnuts, and red sword bean (Gan et al., 2018; Luo et al., 2014; Smeriglio et al., 2017).
Stilbenes are present in low quantities in the human diet, resveratrol being the most characteristic, mainly found in grapes and red wine, mostly in glycosylated forms rather than its cis/trans isomers, as well as oligomers containing different resveratrol units such as δ‐viniferin and ε‐viniferin (Burns et al., 2002; D'Archivio et al., 2007; Vitrac et al., 2005). Other dietary sources with lesser amounts of stilbenes, mainly resveratrol, are peanuts, pistachios, some berries, red cabbage, and spinach (Crozier et al., 2009; D'Archivio et al., 2007; Rivière et al., 2012), as well as certain medicinal remedies such as Polygonum cuspidatum that contains very high levels of resveratrol and its glucoside piceid (Vastano et al., 2000).
Coumarins and derivatives are common in members of the Rutaceae (citrus), and Apiaceae (parsley, celery, etc.) families. They are also found in several species belonging to different botanical families used as herbal medicinal remedies such as Aesculus hippocastanum (horse chestnut), Passiflora incarnata (passion flower), and Hypericum perforatum (St John's wort) (Matos et al., 2015).
Lignans have been found in many plant foods, commonly as glycosides. They are receiving growing attention as precursors of the enterolignans (enterolactone and enterodiol), microbial metabolites that exert potential biological effects (Aehle et al., 2011; Raffaelli et al., 2002). The richest dietary source of lignans, mainly of secoisolariciresinol diglucoside and matairesinol, in lesser amount, is flaxseed (also called linseed). Relatively high amounts of other lignans, such as pinoresinol and lariciresinol, are found in sesame seeds (Milder et al., 2005). Other minor sources include several cereals (triticale and wheat), legumes (soybeans and lentils), vegetables (garlic, asparagus, broccoli, carrots), and fruits (pears, prunes, strawberries, lingonberries, blackcurrants) (Aehle et al., 2011; Gerstenmeyer et al., 2013; Mazur et al., 2000; Raffaelli et al., 2002; Smeds et al., 2007).
1.4 Databases Used to Assess Dietary Exposure to Polyphenols
One of the main tasks in nutritional studies with plant food products is determination of the dietary intake of specific food phytochemicals, and particularly polyphenols, due to the large structural diversity and variability among food products, and the changes occurring with processing, storage, and culinary practices. To help with this task, there are several free access internet‐based databases, two of which are described here.
Phenol Explorer
(
http://phenol-explorer.eu/
). This database is freely accessible and describes the polyphenol content of food, with more than 500 polyphenols and their occurrence in 400 foods. The database also contains a comprehensive description of polyphenol metabolism, including pharmacokinetics data, as well as a description of the effect of food processing and cooking on these metabolites.
Phytohub
(
http://phytohub.eu/
). Phytohub is a comprehensive database of food phytochemicals. It is linked with FooDB (
http://foodb.ca/
) and ITIS (Integrated Taxonomic Information System) (
www.itis.gov/
/) which provides interesting and relevant information regarding the origin of plant foods and food sources. It is the first inventory of all phytochemicals present in foods (>350) commonly ingested in human diets and also includes >560 human and animal metabolites. Phytohub includes a connection with a mass search and structure application, as well as a food search link, which is very useful for metabolomic studies, and identification of discriminant metabolites in nutri‐metabolomic studies.
1.5 Bioavailability, Metabolism, and Bioactivity of Dietary Polyphenols
Over recent decades, spectacular advances have been made through in our understanding of the possible role of dietary polyphenols in preventive nutrition. In fact, for decades, epidemiological and observational studies have been pointing out that dietary polyphenols present in a fruit‐ and vegetable‐rich diet exert protective effects against several chronic degenerative diseases including cardiovascular diseases, diabetes, cancer, and neurodegenerative conditions such as Alzheimer's and Parkinson's diseases, mainly in the context of regular or long‐term intake (Bravo, 1998; Cory et al., 2018; Espín and Tomás‐Barberán, 2005; Fraga et al., 2019; Tresserra‐Rimbau et al., 2014). Moreover, in parallel, extensive preclinical research in animal and cell models has described a wide spectrum of biological activities for many dietary polyphenols beyond the antioxidant properties classically attributed to plants, including antimicrobial, antiinflammatory, and anticarcinogenic properties, displayed in both the digestive tract and systemic tissues (Bravo, 1998; Espín and Tomás‐Barberán, 2005; Del Rio et al., 2013; Fraga
