Natural Bioactive Compounds from Fruits and ...

Natural Bioactive Compounds from Fruits and Vegetables as Health Promoters 3DUW ,, Edited by Luís Rodrigues da Silva CICS – UBI – Health Sciences Research Centre University of Beira Interior Covilhã Portugal &

Branca Maria Silva CICS – UBI – Health Sciences Research Centre University of Beira Interior Covilhã Portugal

Natural Bioactive Compounds from Fruits and Vegetables as Health Promoters Authors: L. SilvaDQG%UDQFD6LOYD ISBN (eBook): 978-1-68108-243-1 ISBN (Print): 978-1-68108-244-8 © 2016, Bentham eBooks imprint. Published by Bentham Science Publishers – Sharjah, UAE. All Rights Reserved. First published in 2016.

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CONTENTS FOREWORD ................................................................................................................................................................ i PREFACE ................................................................................................................................................................... iii LIST OF CONTRIBUTORS ..................................................................................................................................... iv CHAPTER 1 BIOACTIVE COMPOUNDS OF LEGUMES AS HEALTH PROMOTERS ............................. 3 INTRODUCTION ................................................................................................................................................ 4 Bioactive Peptides (BAPs) ............................................................................................................................. 5 Isoflavones .................................................................................................................................................... 7 Other Phenolic Compounds ........................................................................................................................ 10 Carotenoids, Tocopherols and Fatty Acids .................................................................................................. 11 CONCLUDING REMARKS ............................................................................................................................. 12 CONFLICT OF INTEREST ............................................................................................................................. 12 ACKNOWLEDGEMENTS ............................................................................................................................... 12 REFERENCES ................................................................................................................................................... 13 CHAPTER 2 BIOACTIVE COMPOUNDS FROM %UDVVLFDFHDH AS HEALTH PROMOTERS .................. INTRODUCTION .............................................................................................................................................. PHYTONUTRIENTS IN CRUCIFEROUS PLANTS AND FOODS ........................................................... Glucosinolates and Bioactive Isothiocyanates ............................................................................................. Phenolic Compounds .................................................................................................................................... Flavonoids ............................................................................................................................................ Phenolic Acids and Derivatives ........................................................................................................... NUTRIENTS: MINERALS AND VITAMINS ................................................................................................ Minerals ........................................................................................................................................................ Vitamins and Carotenoids ............................................................................................................................ OTHER NUTRIENTS ....................................................................................................................................... FUTURE PERSPECTIVES .............................................................................................................................. CONFLICT OF INTEREST ............................................................................................................................. ACKNOWLEDGEMENTS ............................................................................................................................... REFERENCES ...................................................................................................................................................

27 28 28 31 33 34 36 36 36 37 39 40 41 41 41

CHAPTER 3 BIOACTIVE COMPOUNDS OF TOMATOES AS HEALTH PROMOTERS ........................ INTRODUCTION .............................................................................................................................................. TOMATO BIOACTIVE COMPOUNDS ......................................................................................................... Carotenoids ................................................................................................................................................... Vitamins ....................................................................................................................................................... Phenolic Compounds .................................................................................................................................... Glycoalkaloids .............................................................................................................................................. BIOAVAILABILITY OF TOMATO COMPOUNDS .................................................................................... Bioavailability of Carotenoids ..................................................................................................................... Bioavailability of Vitamins .......................................................................................................................... Bioavailability of Phenolic Compounds ..................................................................................................... Bioavailability of Glycoalkaloids ................................................................................................................. BIOACTIVITY OF TOMATO COMPOUNDS .............................................................................................. Bioactive Properties of Carotenoids ............................................................................................................. Bioactive Properties of Vitamins .................................................................................................................

48 49 50 51 53 56 57 59 59 60 60 61 61 62 63

Bioactive Properties of Phenolic Compounds .............................................................................................. Bioactive Properties of Glycoalkaloids ........................................................................................................ TOMATO AND HUMAN HEALTH ............................................................................................................... Tomato Consumption Improves the Oxidative Status ................................................................................. Tomato Suppresses the NF-κB Activation and Reduces Inflammation ....................................................... Tomato Reduces Inflammation Linked to Obesity, Diabetes and Cholesterol ............................................ Tomato Prevents Cardiovascular Diseases, Atherosclerosis and Hypertension .......................................... Tomato has Antitumour and Anticarcinogenic Properties ........................................................................... Tomato Protects Liver from Hepatotoxicity and Hepatocarcinogenesis ...................................................... SAFETY PRECAUTIONS ................................................................................................................................ INDUSTRIAL APPLICATIONS ...................................................................................................................... CONCLUDING REMARKS ............................................................................................................................. CONFLICT OF INTEREST ............................................................................................................................. ACKNOWLEDGEMENTS ............................................................................................................................... REFERENCES ...................................................................................................................................................

64 65 66 67 67 68 70 72 75 77 78 78 79 79 79

CHAPTER 4 BIOACTIVE COMPOUNDS FROM &DSVLFXPDQQXXP AS HEALTH PROMOTERS .... 92 INTRODUCTION .............................................................................................................................................. 93 POLYPHENOLS ................................................................................................................................................ 95 CAPSAICINOIDS .............................................................................................................................................. 96 Pain Relief .................................................................................................................................................... 97 Anti-Obesity ................................................................................................................................................. 98 Anti-Cancer .................................................................................................................................................. 99 Other Effects .............................................................................................................................................. 100 CAPSINOIDS ................................................................................................................................................... 100 Anti-Obesity ............................................................................................................................................... 100 Anti-Cancer ................................................................................................................................................ 101 CAROTENOIDS .............................................................................................................................................. 101 VITAMINS ....................................................................................................................................................... 101 Ascorbic Acid ............................................................................................................................................. 101 PHYTOSTEROLS ........................................................................................................................................... 102 CONCLUDING REMARKS ........................................................................................................................... 103 CONFLICT OF INTEREST .......................................................................................................................... 104 ACKNOWLEDGEMENTS ............................................................................................................................. 104 REFERENCES ................................................................................................................................................. 104 CHAPTER 5 PHYTOCHEMICAL, NUTRITIONAL, ANTIOXIDANT AND ANTICANCER PROPERTIES OF -XJODQVUHJLD (L.) .................................................................................................................................... 110 INTRODUCTION ............................................................................................................................................ 111 CHEMICAL COMPOSITION AND NUTRITIONAL PROPERTIES ..................................................... 112 Major Components ..................................................................................................................................... 112 Macronutrients ................................................................................................................................... 113 Minor Components ............................................................................................................................. 114 ANTIOXIDANT ACTIVITY AND ASSOCIATED HEALTH BENEFITS .............................................. 117 ANTIMUTAGENIC AND ANTICARCIONAGENIC ACTIVITIES ........................................................ 119 CONCLUDING REMARKS ........................................................................................................................... 122 CONFLICT OF INTEREST .......................................................................................................................... 122 ACKNOWLEDGEMENTS ............................................................................................................................. 122 REFERENCES ................................................................................................................................................. 123

CHAPTER 6 BIOACTIVE COMPOUNDS OF CHESTNUTS AS HEALTH PROMOTERS .................... INTRODUCTION ............................................................................................................................................ PHYSICOCHEMICAL PROPERTIES OF CHESTNUT ........................................................................... PRINCIPAL POSTHARVEST TECHNOLOGIES ..................................................................................... Cold Storage ............................................................................................................................................... Drying ......................................................................................................................................................... Osmotic Dehydration ................................................................................................................................. Irradiation ................................................................................................................................................... Industrial Processing and Other Ways to Prepare Chestnuts for Consumption ......................................... CONCLUDING REMARKS ........................................................................................................................... CONFLICT OF INTEREST ........................................................................................................................... ACKNOWLEDGEMENTS ............................................................................................................................. REFERENCES .................................................................................................................................................

132 133 134 142 142 143 143 144 145 146 146 146 147

CHAPTER 7 BIOACTIVE COMPOUNDS OF HAZELNUTS AS HEALTH PROMOTERS .................... INTRODUCTION ............................................................................................................................................ CHEMICAL COMPOSITION ...................................................................................................................... Proximate Composition .............................................................................................................................. Amino Acids .............................................................................................................................................. Water-Soluble Vitamins ............................................................................................................................ Minerals ...................................................................................................................................................... LIPIDIC COMPOUNDS ................................................................................................................................. Fatty Acids ................................................................................................................................................ Phytosterols ................................................................................................................................................ Vitamin E ................................................................................................................................................... PHENOLIC COMPOUNDS ........................................................................................................................... Phenolic Acids ............................................................................................................................................ Flavonoids .................................................................................................................................................. Tannins ....................................................................................................................................................... HEALTH ASPECTS: EPIDEMIOLOGICAL AND CLINICAL STUDIES ............................................. CONCLUDING REMARKS ........................................................................................................................... CONFLICT OF INTEREST .......................................................................................................................... ACKNOWLEDGEMENTS ............................................................................................................................. REFERENCES .................................................................................................................................................

155 156 157 157 158 159 160 161 161 162 163 165 165 167 168 169 171 171 171 171

CHAPTER 8 BIOACTIVE COMPOUNDS IN COFFEE AS HEALTH PROMOTORS ............................. INTRODUCTION ............................................................................................................................................ BIOACTIVE COMPOUNDS IN COFFEE AND THEIR PHYSIOLOGICAL EFFECTS ..................... Chlorogenic Acids ...................................................................................................................................... Caffeine ...................................................................................................................................................... Trigonelline ................................................................................................................................................ Melanoidins ................................................................................................................................................ Diterpenes: Kahweol and Cafestol ............................................................................................................. HEALTH BENEFITS OF COFFEE .............................................................................................................. Antioxidant Effect ...................................................................................................................................... Diabetes ...................................................................................................................................................... Mechanism of Action .......................................................................................................................... Cancer ......................................................................................................................................................... Breast Cancer ..................................................................................................................................... Uterus Cancer ...................................................................................................................................

180 181 183 183 185 187 188 190 191 191 192 192 193 193 193

Prostate Cancer .................................................................................................................................. Liver Cancer ....................................................................................................................................... Colorectal Cancer .............................................................................................................................. Mechanisms of Action ........................................................................................................................ Parkinson’s Disease .................................................................................................................................... Mechanism of Action .......................................................................................................................... Age-Related Cognitive Decline and Alzheimer’s Disease ......................................................................... Age-related Cognitive Decline ........................................................................................................... Alzheimer’s Disease and Dementia .................................................................................................... Mechanism of Action .......................................................................................................................... ANALYTICAL METHODS FOR THE DETERMINATION OF BIOACTIVE COMPOUNDS COFFEE .................................................................................................................................................. Determination of Chlorogenic Acids /Phenolic Compounds ..................................................................... Determination of Caffeine .......................................................................................................................... Determination of Diterpenes ..................................................................................................................... Determination of Trigonelline and Nicotinic Acid .................................................................................... Recovery of Bioactive Compounds from Spent Coffee ............................................................................. CONCLUDING REMARKS ........................................................................................................................... CONFLICT OF INTEREST .......................................................................................................................... ACKNOWLEDGEMENTS ............................................................................................................................. REFERENCES .................................................................................................................................................

194 194 194 195 196 196 196 196 197 197 IN 197 199 201 203 204 204 205 206 206 206

CHAPTER 9 BIOACTIVE COMPOUNDS OF RICE AS HEALTH PROMOTERS ................................... INTRODUCTION ............................................................................................................................................ Traditional Therapeutic Uses of Rice ......................................................................................................... Composition and Antioxidant Effects of the Bioactive Compounds in Rice ............................................. Health Promoting Properties of Rice ......................................................................................................... Effect of Processing on the Bioactive Compounds in Rice ....................................................................... CONCLUDING REMARKS ........................................................................................................................... CONFLICT OF INTEREST .......................................................................................................................... ACKNOWLEDGEMENTS ............................................................................................................................. REFERENCES .................................................................................................................................................

221 222 222 223 224 227 228 228 229 229

SUBJECT INDEX .................................................................................................................................................... 235

i

FOREWORD For centuries, humans have considered food only as an “energy” source for survival. Clarification of nutritional relevant components, as protein, fat, carbohydrates, minerals and vitamins, was determinant to understand metabolic needs, and to adjust consumption patterns. However, this oversimplified definition of food resulted in processed foods composed by mixtures of ingredients rich in these components, while diet is increasingly claimed as being responsible for the most common diseases of modern society: cardiovascular diseases, obesity, and cancer. When we look upon food from this simplified perspective, it is as if we are regarding food without its “soul”. Indeed, although being difficult to demonstrate causality between food and health, there is now appreciable epidemiologic evidence for the protective role of diets rich in fruits and vegetables, being the Mediterranean diet an interesting example. These foods have thousands of components without nutritional essentiality that have been neglected. The interest on these components has increased tremendously in the last two decades, seeking to identify the dietary bioactive components (i.e., those that have a measurable impact on human health), their amounts, and availability. Simultaneously, it is also becoming clear that each one of these components has different effects and potencies when ingested alone or when taking its part in the complex network of molecules present in whole foods. These are amazing days for food scientists because we are closer to understand these bioactive compounds, while the consumer is following closely scientific advances, being increasingly interested in the health properties of foods. The editors took an enormous and successful effort to assemble a huge variety of knowledge on different natural bioactive components in foods, bringing together experts working of different fields of food composition and health. Following a first volume on fruits, this second volume was written to provide readers with a comprehensive review of bioactive constituents in several legumes, nuts, seeds and cereals, from the most traditional ones, as rice or tomatoes, to emerging potentials in modern nutrition, as quinoa or coffee residues. This assembled knowledge allows the reader to get acquainted with the most promising bioactive compounds in different foods, understand the care needed to preserve their bioactivity during storage or processing, while revealing also the hidden bioactive potential of commonly rejected parts, as shells or seeds.

ii

Therefore, this book is designed for food scientists, nutritionists, pharmaceuticals, physicians, food industrials, as well as for health-conscious consumers.

José Alberto Pereira Mountain Research Centre (CIMO) School of Agriculture Polytechnic Institute of Bragança Portugal Susana Casal REQUIMTE / Bromatology Service Faculty of Pharmacy University of Porto Portugal

iii

PREFACE Plants have been widely used as food and medicines, since they provide, not only essential nutrients required for human life, but also other bioactive compounds which play important roles in health promotion and disease prevention, commonly known as phytochemicals. Moreover, in the recent years, the impact of lifestyle and dietary choices for human health has increased the interest in fruits and vegetables, as well as in foods enriched with bioactive compounds and nutraceuticals. In fact, epidemiological studies have consistently shown that the Mediterranean diet, characterized by the daily consumption of fruits and vegetables, is strongly associated with reduced risk of developing a wide range of chronic diseases, such as cancer, diabetes, neurodegenerative and cardiovascular diseases. Phytochemicals are secondary metabolites present in fruits and vegetables in low concentrations that have been hypothesized to reduce the risk of several pathological conditions. There are thousands of dietary phytochemicals, namely flavonoids, phenolic acids, glucosinolates, terpenes, alkaloids, between many other classes of compounds, which present different bioactivities, such as antioxidant, antimutagenic, anticarcinogenic, antimicrobial, anti-inflammatory, hypocholesterolemic, hypoglicemic and other clinically relevant activities. The evidence suggests that the health benefits of fruits and vegetables consumption are attributed to the additive and synergistic interactions between these phytocomponents. Therefore, nutrients and bioactive compounds present in fruits and vegetables should be preferred instead of unnatural and expensive dietary supplements. In this ebook, we provide an overview about the different classes of phytochemicals commonly found in fruits and vegetables, highlighting their chemical structures, occurrence in fruits and vegetables, biological importance and mechanisms of action. Volume 2 is dedicated to the study of several legumes, nuts, seeds and cereals.

Luís Rodrigues da Silva CICS – UBI – Health Sciences Research Centre University of Beira Interior Portugal

iv

List of Contributors Adriana M. S. Sousa

CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal

Ana R. Nunes


Álvaro Peix

Instituto de Recursos Naturales y Agrobiología, IRNASA-CSIC, Salamanca, Spain; Unidad Asociada Universidad de Salamanca- CSIC ‘Interacción PlantaMicroorganismo’, Salamanca, Spain

Branca M. Silva


Carlos Albuquerque

IPV - ESSV – Polytechnic Institute of Viseu, Higher Health School of Viseu, 3500-843, Viseu, Portugal

Charu Lata Mahanta

Department of Food Engineering and Technology, Tezpur University, Assam, India

Cristina GarcíaViguera

Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS (CSIC), P.O. Box 164, 30100 Campus University Espinardo, Murcia, Spain; Phytochemistry Lab, Food Sci. & Technology Dept., CEBAS-CSIC, Murcia, Spain

Diego A. Moreno

Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS (CSIC), P.O. Box 164, 30100 Campus University Espinardo, Murcia, Spain; Phytochemistry Lab, Food Sci. & Technology Dept., CEBAS-CSIC, Murcia, Spain

Elsa Ramalhosa

Mountain Research Centre (CIMO), School of Agriculture, Polytechnic Institute of Bragança, Campus de Sta Apolónia, Apartado 1172, 5301-855 Bragança, Portugal

Encarna Velázquez

Departamento de Microbiología y Genética. Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain; Unidad Asociada Universidad de Salamanca- CSIC ‘Interacción PlantaMicroorganismo’, Salamanca, Spain

Gonçalo D. Tomás

1CICS – UBI – Health Sciences Research Centre, University of Beira Interior , 6201-506 Covilhã, Portugal

Isabel C.F.R. Ferreira

Mountain Research Centre (CIMO), ESA, Polytechnic Institute of Bragança, Campus de Santa Apolónia, Ap. 1172, 5301-855 Bragança, Portugal

v

Joana S. Amaral

REQUIMTE-LAQV, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Portugal; ESTiG, Instituto Politécnico de Bragança, Bragança, Portugal

João A. Lopes

iMed. ULisboa, Departamento de Farmácia Galénica e Tecnologia Farmacêutica, Faculdade de Farmácia, Universidade de Lisboa, Lisbon, Portugal

Jorge M.G. Sarraguça

LAQV/REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal

José A. Pereira

Mountain Research Centre (CIMO), School of Agriculture, Polytechnic Institute of Bragança, Campus de Sta Apolónia, Apartado 1172, 5301-855 Bragança, Portugal

José Pinela

Mountain Research Centre (CIMO), ESA, Polytechnic Institute of Bragança, Campus de Santa Apolónia, Ap. 1172, 5301-855 Bragança, Portugal; REQUIMTE/LAQV, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, n° 228, 4050-313 Porto, Portugal

Lorena Carro

Departamento de Microbiología y Genética. Facultad de Farmacia, Universidad de Salamanca, Salamanca , Spain

Luís R. Silva

CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal; IPCB – ESALD – Polytechnic Institute of Castelo Branco, Higher Health School Dr. Lopes Dias, 6000-767, Castelo Branco, Portugal; LEPABE – Department of Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal

Mafalda C. Sarraguça


Marco G. Alves


M. Beatriz P.P. Oliveira

REQUIMTE/LAQV, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, n° 228, 4050-313 Porto, Portugal; REQUIMTE-LAQV, Departamento de Ciências Químicas, Faculdade de Farmácia,, Universidade do Porto, Portugal

María Elena Cartea

Group of Genetics, Breeding and Biochemistry of Brassicas, MBG-CSIC, Pontevedra, Spain

Marta Francisco


Miguel Lopo


Nieves Baenas

Phytochemistry Lab, Food Sci. & Technology Dept, CEBAS-CSIC, Murcia, Spain

vi Pablo Velasco


Pedro F. Oliveira

CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal; Department of Microscopy, Laboratory of Cell Biology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, 4050-313 Porto, Portugal

Ricardo N.M.J. Páscoa


Sangeeta Saikia

Department of Food Engineering and Technology, Tezpur University, Assam, India

Susana Casal

LAQV-REQUIMTE, Chemistry Department, Faculty of Pharmacy, Oporto University, Porto, Portugal

Teresa Delgado

Mountain Research Centre (CIMO) - School of Agriculture, Polytechnic Institute of Bragança, Bragança, Portugal LAQV-REQUIMTE, Chemistry Department, Faculty of Pharmacy, Oporto University, Porto, Portugal

Natural Bioactive Compounds from Fruits and Vegetables, 2016, 27-47

27

CHAPTER 2

Bioactive Compounds from Brassicaceae as Health Promoters Nieves Baenas1,†, Marta Francisco2,†, Pablo Velasco2, María Elena Cartea2, Cristina García-Viguera1, Diego A. Moreno1,* 1

Phytochemistry Lab, Food Sci. & Technology Dept., CEBAS-CSIC, Murcia, Spain

2


†

These authors contributed equally to this work

Abstract: This work provides an up to date review of the information available about bioactive compounds present in the Brassicaceaefamily (glucosinolates, phenolics and vitamins) in relation to human health. The Brassicaceaeplant family includes a large variety of species and cultivars, some of the most known are Brassica oleracea (e.g. broccoli, cabbage, Brussels sprouts), Brassica rapa (e.g. turnips), Brassica napus (e.g. rapeseed), Raphanus sativus (radishes), and Sinapis alba (mustards). In the recent years, these crops are increasingly consumed for possible health benefits as a good source of bioactive compounds. The sulphur containing compounds glucosinolates are almost exclusively found in this family, being their beneficial health effect supposed to be induced by their hydrolysis products, the isothiocyanates. In in vitro (human cell lines) and in vivo studies (animal models and human intervention assays) isothiocyanates have demonstrated their protective effects in carcinogenesis, chronic inflammation and neurodegeneration. The phenolic compounds mainly studied are flavonols, anthocyanins and hydroxycinnamic acids, which principal bioactivity is their antioxidant capacity. The carotenoids β-carotene, lutein and zeaxanthin, as well as, vitamins C, E and K have also been considered as nutrients with biological activity. The phytochemical wealth of Brassica foods is gathering attention from the scientific community for being potentially protective for the cardiovascular system and against certain types of cancer, and neurological disorders, mainly because of their antiinflammatory and antioxidant properties. *

Corresponding author Diego A. Moreno: C.E.B.A.S.-C.S.I.C. – FOOD SCI. & TECHNOL. DEPT., Campus de Espinardo – Edificio 25, P.O. BOX 164, E-30100 Espinardo, Murcia (SPAIN); Tel: +34 968 39 6369; Fax: +34 968 39 6213; Email: [email protected]. Luís Rodrigues da Silva and Branca Maria Silva (Eds.) All rights reserved-© 2016 Bentham Science Publishers

28 Natural Bioactive Compounds from Fruits and Vegetables

Baenas et al.

Even it is not yet possible to recommend a particular “daily dose” for human consumption of cruciferous foods for disease prevention, there is growing evidence regarding the protective effects of Brassica bioactive compounds for health via regulation of signaling pathways and cellular metabolism

Keywords: Antiinflammatory, Antioxidant, Brassicaceae, Cardiovascular disease, Carotenoids, Chemoprevention, Cruciferous, Glucosinolates, Isothiocyanates, Minerals, Neurodegeneration, Phenolic compounds, Vitamins. INTRODUCTION Brassicaceae family, commonly termed the mustard family or Cruciferae, represents a monophyletic group including approximately 350 genera and 3,700 species, which has been the subject of much scientific interest, with many crops of socioeconomical relevance (food and spices, condiments, oils), forage or ornamental. This family includes common species of food staples such as: broccoli, cauliflower, Brussels sprouts, cabbages, belonging to Brassica oleracea; turnips and Chinese cabbages of Brassica rapa; oilseeds of Brassica napus (rapeseed, leaf rape); mustards (Sinapis alba); and radishes (Raphanus sativus), among others. Brassicaceae crops are dated in Europe and northern Asia for at least 600 years and in the earlier part of the 20th century they have grown in North America, with productions in Europe around the 70 million tons/annum [1]. Brassicaceae crops are widely distributed in the World: Southwestern and Central Asia, Mediterranean Europe, and North and South America. Brassica production and consumption has increased worldwide in the last years, but only from a few cultivated genera [2]. There are numerous further species with great potential for exploitation in 21st century agricultural and food commodities, particularly as sources of bioactive phytonutrients. PHYTONUTRIENTS IN CRUCIFEROUS PLANTS AND FOODS The Brassicaceae vegetables have been widely studied for their beneficial effects on human health through epidemiological studies [3], being nutritive foods rich in essential nutrients and phytochemicals that may act synergistically in the food matrix to modulate the cell metabolism and help in the prevention and treatment

Compounds from Brassicaceae

Natural Bioactive Compounds from Fruits and Vegetables

29

of certain types of cancer, cardiovascular health problems, and neurodegenerative conditions of the aging human being (Table 1) [4]. Although vegetable cruciferous plants are sources of fiber, folate, vitamins (A, E, C, and K) and minerals (Ca, Fe, K, Cu, Zn, P, Mn, and Mg, among others), the major body of evidence in the scientific literature is concentrated in the contents of secondary metabolites, such as flavonoids and carotenoids, and specially glucosinolates (GLSs). These compounds are mainly present in this family and are hydrolyzed to isothiocyanates (ITCs), which may be responsible of the chemoprotective activity and the reduction in the risk of suffering a number of cancers associated with the intake of cruciferous foods. Also the health-promoting effects of crucifers have been attributed at least in part to their bioactive composition rich in natural antioxidants, such as vitamins (C, A, E, K, etc.), carotenoids and phenolic compounds [5]. Table 1. Nutrients and phytochemicals presents in cruciferous plants and their physiological functions. Compounds and chemical structures

Physiological functions

References

GLSs and ITCs

Induction of detoxification enzymes Apoptosis and arrest of tumor cell growth Decrease adipogenesis and inflammation Reduce oxidative stresses

[4, 6 - 8]

Flavonols

Prevent the oxidation of LDL Capillary protective effect Reduce serum levels of glucose Tumor inhibitory effect Anti-inflammatory, antimicrobial and anti-allergic

[5, 9, 10]


Baenas et al.

7DEOH FRQWG

Compounds and chemical structures Anthocyanins

Physiological functions Antioxidant power and antigenotoxic

References [11]

Hydroxycinnamic acids

Cellular defense of peroxynitrite-mediated disorders

[12, 13]

Vitamins and β-carotene

Protection against free radicals Cytoprotective functions Preserve protein integrity

[14 - 17]

Minerals Fundamentally the elements or Mainly the elements K, Ca, Na, Mg, Fe, Zn, Se and Mn.

Participation in metabolic activities Biochemical and nutritional functions

[3, 18]



31

Glucosinolates and Bioactive Isothiocyanates The GLSs are secondary metabolites, sulphur and nitrogen-containing compounds with a common structure which comprises a β-D-thioglucose group, a sulphonated oxime moiety, and a variable aglycone side-chain derived from natural amino acids, that determine the final structure, being mainly derived from methionine, tryptophan or phenylalanine. Therefore, GLSs can be classified by their precursor amino acids as aliphatic (derived from alanine, leucine, methionine or valine), aromatic (from phenylalanine or tyrosine) and indolic (from tryptophan). The studies of the profile of GLSs indicate significant differences among species, according to the type and intensity of environmental stress, growth conditions and storage, processing and cooking methods [3, 19 - 21]. The GLSs load in plant tissues is highly variable, being seeds the plant part with the highest contents, followed by the germinating seeds and sprouts –that may present a 10-fold increase compared to commercial inflorescences or heads from adult plants– and generally followed by leaves and roots. This amount of GLSs may range from 1% to 10% (on a dry weight basis) in the seeds of some species [2]. GLSs are hydrolyzed to ITCs, their biologically active hydrolysis metabolites, both by the action of the enzyme myrosinase (thioglucoside glycohydrolase EC EC:3.2.1.147), which comes into contact with GLSs when there is a tissue disrupted by crushing or herbivory/chewing or by the action of the gut microflora upon human ingestion. Intact GLSs have no known biological activity; thus, the bioavailability of bioactive hydrolysis products is dependent not only on ingestion of GLSs, but also on their conversion prior to passage across the gut wall [6]. Inactivation of the plant myrosinase also decreases bioavailability of ITCs because the enzyme is heat sensitive, as occurs when Brassica vegetables are ingested cooked, thus boiling or steaming for more than 3-5 min and blanching previous frozen production will lead to loss of its activity [22]. The bioavailability of GLSs is measured by analyzing the mercapturic acid pathway products (mercapturates) which acts as a bioindicator or marker of intake and also are useful to study the bioaccesibility and bioavailability of the GLSs breakdown products, the ITCs, which gives rise to N-acetyl-cysteine conjugates. In vitro and in vivo studies mainly focused in the use of sulforaphane from


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broccoli (SFN), has shown the influence of this bioactive compound on the cellular cytoprotective mechanisms involved in all the stages of development of cancer, through the selective induction of detoxification Phase II enzymes, to detoxify the products (electrophilic metabolites) of the activity of phase I enzymes to avoid the damage on the DNA (glutathione S-transferases, UDP-glucuronosyl transferases, and quinone reductase) [23] and through the limitation of the activity of Phase I enzymes [24]. A diet of 3-5 servings per week is sufficient to cause a 30% or 40% decrease in risk for a number of cancers [25]. Glucoraphanin (GRA) is the GLS precursor of the bioactive ITC SFN, which is being widely studied as a potent protector of carcinogenesis. Histone deacetylases (HDAC), which remove acetyl groups from proteins, has been studied recently and SFN metabolites were reported as inhibitors altering their gene expression and protein function [26]. One major step to determine the absorption of SFN is the hydrolysis of GRA by the action of the enzyme myrosinase. When comparing the intake of supplements rich in GRA with inactivated myrosinase, against the intake of fresh broccoli sprouts with the active enzyme, Clarke et al., observed a much limited SFN absorption in healthy adults (7-fold lower) [27]. Also Vermeulen et al., observed higher excretion of SFN metabolites after consumption of raw versus cooked broccoli – by 11% [28]. Other interesting work showed in plasma and urine higher levels of total SFN metabolites (3-5 times) in fresh broccoli sprouts consumers compared to myrosinase-treated broccoli sprouts extract containing SFN but not GRA; therefore, GRA hydrolysis to produce SFN is not the only one factor affecting the absorption of SFN, other compounds present in the broccoli sprout food matrix, such as minerals, vitamins, other nutrients and phytochemicals and fiber may facilitate the transport of SFN across cell membranes [29]. In SFN bioavailability, also the total amount of SFN estimated could derive from the interconversion of erucin, from the GLS glucoerucin, to SFN in vivo [8]. Not only the ITC SFN, but also erucin, from the precursor GLS glucoerucin, iberin from glucoiberin, sulforaphene from glucoraphenin (which differs from GRA by a double bond), phenethyl ITC from gluconasturtiin, and indole--carbinol (I3C) from indole GLSs (4-Hydroxi-, 4-Methoxy-, Neo- and glucobrassicin), have been studied because their bioactivity, triggering the



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transcription factor Nrf2 into de nucleus, where the antioxidant response element (ARE) promoter region activate multiple genes, including both phase II detoxification enzymes and several antioxidant enzymes, among others, and induce cell cycle arrest and apoptosis [30]. Recent studies have shown that the I3C plays important roles in apoptosis and arrest of cell growth in breast and prostate cancer cells [31], and may potential benefits in preventing obesity and its comorbidities through different mechanisms including the reduction of adipogenesis and inflammation, and the increased thermogenesis [32]. Further in vitro and in vivo assays to understand GLSs bioavailability, would encourage the use of cruciferous vegetables as preventive and health food within the confines of animal studies or human trial for any form of cancer. Phenolic Compounds Phenolic compounds are ubiquitous phytochemicals in plants and plant foods (more than 8,000 described, characterized by having at least one aromatic ring with one or more hydroxyl groups attached). The structure of phenolic compounds may be very simple and with low molecular-weight, with single aromatic-ringed compounds or very complex (i.e., tannins and other (poly)phenolics) [33, 34]. These compounds perform a variety of functions in the plant, generally centered on responses to pathogen attacks, UV protection, colour and sensory characteristics [35]. The phenolic compounds may be classified according to their number and arrangements of their carbon atoms in flavonoids (flavonols, flavones, flavan-3-ols, anthocyanidins, flavanones, isoflavones and others) and non-flavonoids (phenolic acids, hydroxycinnamates, stilbenes and others) [36]. Diets rich in plant-derived foods rich in phenolic compounds, such as those from the cruciferous family, have been reported to exert health-promoting benefits at different levels: anti-inflammatory, enzyme inhibition, antimicrobial, antiallergic, vascular and cytotoxic antitumor activity, and the most widely cited action of phenolics, their antioxidant activity [37, 38]. Phenolic compounds can play important roles in scavenging free radicals and up-regulation of certain metalchelation reactions. The reactive oxygen species (ROS, singlet oxygen,


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peroxynitrite, hydrogen peroxide), must be eliminated from cells to maintain healthy metabolic functions, and such reductions are positively associated with the ion transport systems and may affect the redox signaling in the cells [34]. Despite the beneficial effects of phenolic compounds it must be taken into account that only a small percentage of the dietary phenolics get inside the cells and are absorbed and metabolized. The plasma concentrations after intake of polyphenolrich foods depend on the food source, and the polyphenol chemistry, and for example, it may vary from 0.3–0.75 μmol/L after consumption of 80–100 mg quercetin equivalents [39]. Moreover, (poly)phenolics are modified during their metabolism in the gastrointestinal tract and these modifications involve conjugation to produce glucuronides or sulphate conjugates by intestinal and/or hepatic detoxification enzymes. However, the major part of these molecules is metabolized by the colonic microflora rendering the so called microbial metabolites. Those microbial metabolites can be analysed in blood (plasma) and urine extractions, after ingestion, but only very small fraction of non-conjugated phenols in their original form can be found. This implies that these microbial metabolites rather than the native phenolics are responsible for the beneficial biological effects in the body [33]. Brassica vegetables are generally rich in polyphenols, although the profile and content of those compounds in the plant may vary depending e.g. on climatic conditions and harvest season [14, 40 - 42]. Moreover, differences in phenolic content can be expected between different cultivars as well as within plant organs [43]. Food processing may also affect phenolic content [44 - 47]. Phenolic contents may vary from 15.3 mg·100g-1 in white cabbage (on a fresh weight basis), to 337 mg·100g-1 in broccoli. Cartea and co-workers [48] extensively reviewed the phenolic profiles in many different species of Brassicaceae and the most widespread and diverse group of polyphenols in these species are the flavonoids (mainly flavonols, but also anthocyanins) and the phenolic acids. Flavonoids Flavonoids are low molecular weight plant-secondary metabolites, consisting of 15 carbon atoms with two aromatic rings (A and B), connected by a three-carbon bridge (C6–C3–C6) configuration that usually in the form of a C-heterocyclic



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ring. The flavonoids described in Brassica spp. are O-glycosides of quercetin, kaempferol and isorhamnetin. Besides, they may be conjugated with different organic acids, most frequently at the 3-position of the C-ring, but substitutions may be also placed in the 5, 7, 4´, 3´ and 5´ positions [33]. To date, more than 20 flavonols have been described in Brassica vegetables such as kale, white cabbage, cauliflower, and broccoli as well as in B. napus and B. rapa leaves. Among them, the main flavonols were identified as kaempferol and quercetin 3-O-sophoroside7-O-glucosides and combinations with hydroxycinnamic acids (i.e., kaempferol and quercetin 3-O-(caffeoyl/sinapoyl)-sophoroside-7-O-glucoside). In the B. rapa group, in addition to quercetin and kaempferol derivates, it can be found derivatives of the flavonol isorhamnetin. In cruciferous varieties for fresh-cut and baby leaf supply including Diplotaxis erucoides L., D. tenuifolia L., Eruca sativa L., Bunias orientalis L., and Nasturtium officinale, quercetin and kaempferol glycosylated derivatives are the major flavonols [38, 48]. The glycosylated flavonols (3-sophoroside-7-glucosides of kaempferol) are receiving more attention in terms of beneficial health effects such as reduction in the risk of suffering certain age-related chronic health problems [38]. Accordingly, quercetin glycosides found at high concentrations in broccoli displayed the ability to prevent the oxidation of LDL by scavenging free radicals and chelating transition metal ions [9]. As a result, quercetin glycosides may help against certain conditions relevant to adult health: cancer, atherosclerosis and chronic inflammation [9]. On the other hand, isorhamnetin glycosides in mustard leaves were named responsible for the hypoglycemic effect using an antioxidant capacity test [49]. Anthocyanins are also present in Brassica vegetables conferring red pigmentation in red cabbages, red radishes, purple cauliflowers and broccolis. The major anthocyanins identified in these crops are cyanidin derivatives. In red cabbage and broccoli sprouts the major anthocyanins identified were the cyanidin 3-O-(sinapoyl)(feruloyl) diglucoside-5-O-glucoside and the cyanidin 3-O-(sinapoyl)(sinapoyl) diglucoside-5-O-glucoside [50]. The biological activity of the anthocyanins have been related also with the antioxidant capacity and the antigenotoxic properties, also repairing the cytological injuries caused by Cu2+ stress on lymphocytes [11].


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Phenolic Acids and Derivatives The compounds present in the phenolic acids class are consisting in two groups, the hydroxybenzoic and the hydroxycinnamic acids. The hydroxybenzoates include gallic, p-hydroxybenzoic, protocatechuic, vanillic and syringic acids, which have the C6–C1 structure in common. In the hydroxycinnamic acids, the compounds are aromatic with a three-carbon side chain (C6–C3), being caffeic, ferulic, p-coumaric and sinapic acids the most common in Brassicas. It is common to find the phenolic acids conjugated also with sugars or with other hydroxycinnamic acids [48]. This phenolic class is abundant in B. oleracea crops, such as kale, cabbage, broccoli, and cauliflower. In these crops, hydroxycinnamoyl gentiobiosides (1-O-caffeoylgentiobiose and 1,2,6-tri-Osinapoylgentiobiose) and hydroxycinnamoylquinic (5-caffeoyl quinic acid) acids are the major representatives [51]. The antioxidant scavenger properties of Brassicaextracts rich in phenolic acids have also been proved in vivo. As a result, the intervention in human subjects with a diet rich in Brussels sprouts showed a reduction on DNA damage in terms of a decreased excretion 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in urine [52]. It has been also reported that even with a short intervention, with broccoli sprouts in rats, a strong protection in the heart against oxidative stress and cell death caused by ischemia-reperfusion or diabetes, can be measured [12]. The sinapic acids, also present in high amounts in cruciferous foods, may also contribute to the cellular defense mechanisms avoiding peroxynitrite-mediated disorders [13]. NUTRIENTS: MINERALS AND VITAMINS Minerals The essential minerals (Na, K, Ca, Mg, Cl and P) are required in high amounts in diet (>50 mg/day), while the metals and trace elements (Fe, Zn, Cu, Mn, I, F, Se, Cr, Mo, Co, Ni) are needed in much lower concentrations (