ebook img

Flavonoids: Biosynthesis, Biological Effects and Dietary Sources (Nutrition and Diet Research Progress) PDF

388 Pages·2009·8.62 MB·English
Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.

Preview Flavonoids: Biosynthesis, Biological Effects and Dietary Sources (Nutrition and Diet Research Progress)

NUTRITION AND DIET RESEARCH PROGRESS SERIES F : B , LAVONOIDS IOSYNTHESIS B E IOLOGICAL FFECTS AND DIETARY SOURCES No part of this digital document may be reproduced, stored in a retrieval system or transmitted in any form or by any means. The publisher has taken reasonable care in the preparation of this digital document, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained herein. This digital document is sold with the clear understanding that the publisher is not engaged in rendering legal, medical or any other professional services. NUTRITION AND DIET RESEARCH PROGRESS SERIES Diet Quality of Americans Nancy Cole and Mary Kay Fox 2009. ISBN: 978-1-60692-777-9 School Nutrition and Children Thomas J. Baxter 2009. ISBN: 978-1-60692-891-2 Appetite and Nutritional Assessment Shane J. Ellsworth and Reece C. Schuster 2009. ISBN: 978-1-60741-085-0 Flavonoids: Biosynthesis, Biological Effects and Dietary Sources Raymond B. Keller 2009. ISBN: 978-1-60741-622-7 NUTRITION AND DIET RESEARCH PROGRESS SERIES F : B , LAVONOIDS IOSYNTHESIS B E IOLOGICAL FFECTS AND DIETARY SOURCES RAYMOND B. KELLER EDITOR Nova Science Publishers, Inc. New York Copyright © 2009 by Nova Science Publishers, Inc. All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic, tape, mechanical photocopying, recording or otherwise without the written permission of the Publisher. For permission to use material from this book please contact us: Telephone 631-231-7269; Fax 631-231-8175 Web Site: http://www.novapublishers.com NOTICE TO THE READER The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers’ use of, or reliance upon, this material. Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA Flavonoids : biosynthesis, biological effects and dietary sources / [edited by] Raymond B. Keller. p. ; cm. Includes bibliographical references and index. ISBN 978-1-61761-914-4 (Ebook) Published by Nova Science Publishers, Inc. (cid:30)  New York CONTENTS Preface vii Chapter 1 Bioavailability and Metabolism of Dietary Flavonoids – Much Known – Much More to Discover 1 David E. Stevenson, Arjan Scheepens and Roger D. Hurst Chapter 2 Cytoprotective Activity of Flavonoids in Relation to Their Chemical Structures and Physicochemical Properties 53 Jingli Zhang and Margot A. Skinner Chapter 3 Oligomeric Nature, Colloidal State, Rheology, Antioxidant Capacity and Antiviral Activity of Polyflavonoids 97 A.Pizzi Chapter 4 Grapefruit Flavonoids: Naringin and Naringinin 141 Ricky W. K. Wong and A. Bakr M. Rabie Chapter 5 Development of Promising Naturally Derived Molecules to Improve Therapeutic Strategies 181 Dominique Delmas, Frédéric Mazué, Didier Colin, Patrick Dutartre and Norbert Latruffe Chapter 6 Effect of a Diet Rich in Cocoa Flavonoids on Experimental Acute Inflammation 213 M. Castell, A. Franch, S. Ramos-Romero, E. Ramiro-Puig, F. J. Pérez-Cano and C. Castellote Chapter 7 Mechanisms at the Root of Flavonoid Action in Cancer: A Step Toward Solving the Rubik's Cube 231 Maria Marino and Pamela Bulzomi Chapter 8 Antiophidian Mechanisms of Medicinal Plants 249 Rafael da Silva Melo, Nicole Moreira Farrapo, Dimas dos Santos Rocha Junior, Magali Glauzer Silva, José Carlos Cogo, Cháriston André Dal Belo, Léa Rodrigues-Simioni, Francisco Carlos Groppo and Yoko Oshima-Franco vi Contents Chapter 9 Molecular Targets of Flavonoids during Apoptosis in Cancer Cells 263 Kenichi Yoshida Chapter 10 Flavan-3-ol Monomers and Condensed Tannins in Dietary and Medicinal Plants 273 Chao-Mei Ma and Masao Hattori Chapter 11 Chemotaxonomic Applications of Flavonoids 291 Jacqui M. McRae, Qi Yang, Russell J. Crawford and Enzo A. Palombo Chapter 12 Bioanalysis of the Flavonoid Composition of Herbal Extracts and Dietary Supplements 301 Shujing Ding and Ed Dudley Chapter 13 Antibacterial Effects of the Flavonoids of the Leaves of Afrofittonia Silvestris 315 Kola’ K. Ajibesin Chapter 14 Why Is Bioavailability of Anthocyanins So Low? 323 Sabina Passamonti Index 331 PREFACE Flavonoids, also referred to as bioflavonoids, are polyphenol antioxidants found naturally in plants. They are secondary metabolites, meaning they are organic compounds that have no direct involvement with the growth or development of plants. Flavonoids are plant nutrients that when consumed in the form of fruits and vegetables are non-toxic as well as potentially beneficial to the human body. Flavonoids are widely disbursed throughout plants and are what give the flowers and fruits of many plants their vibrant colors. They also play a role in protecting the plants from microbe and insect attacks. More importantly, the consumption of foods containing flavonoids has been linked to numerous health benefits. Though research shows flavonoids alone provide minimal antioxidant benefit due to slow absorption by the body, there is indication that they biologically trigger the production of natural enzymes that fight disease. Recent research indicates that flavonoids can be nutritionally helpful by triggering enzymes that reduce the risk of certain cancers, heart disease, and age-related degenerative diseases. Some research also indicates flavonoids may help prevent tooth decay and reduce the occurrence of common ailments such as the flu. These potential health benefits, many of which have been proven, have become of particular interest to consumers and food manufacturers. Foods that contain high amounts of flavonoids include blueberries, red beans, cranberries, and blackberries. Many other foods, including red and yellow fruits and vegetables and some nuts, also contain flavonoids. Red wine and certain teas also are rich in flavonoids. Chapter 1 - There have been many epidemiological studies linking flavonoid intake to health benefits and many in vitro studies demonstrating various biological effects of flavonoids that should be reflected by health benefits. It has been widely assumed that these observations are linked and dietary flavonoids are readily absorbed into the circulation and influence many regulatory and signalling pathways in tissues. More recently, it has become apparent that only a small proportion of dietary flavonoid intake is actually absorbed directly and measured relative absorption varies about 2 orders of magnitude between different compounds. It is also apparent that most of the dietary load of flavonoids finds its way to the colon where the numerous and varied microflora metabolise them into simpler but much more bioavailable compounds. Further complications to the bioavailability of flavonoids are added by human Phase II conjugative metabolism, which is thought to convert most absorbed flavonoids into polar conjugates. viii Raymond B. Keller There is no doubt that some unconjugated flavonoids do get into the circulation at low concentrations, but they are quantitatively swamped by the bulk of flavonoid conjugates and colonic metabolites. In contrast with the much-studied metabolism of flavonoids, relatively little is known about the biological activities of their conjugates and metabolites, although what is known comes from a predominance of in vitro studies and suggests that the metabolites do have numerous and significant biological activities. Hence very little is known about the real and mostly indirect benefits and mechanisms of action of dietary flavonoids. In this review, the current state of knowledge in this area is discussed, with the aim of stimulating further research (especially by intervention studies) to aid greater understanding. Chapter 2 - Flavonoids are widely distributed in fruit and vegetables and form part of the human diet. These compounds are thought to be a contributing factor to the health benefits of fruit and vegetables in part because of their antioxidant activities. Despite the extensive use of chemical antioxidant assays to assess the activity of flavonoids and other natural products that are safe to consume, their ability to predict an in vivo health benefit is debateable. Some are carried out at non-physiological pH and temperature, most take no account of partitioning between hydrophilic and lipophilic environments, and none of them takes into account bioavailability, uptake and metabolism of antioxidant compounds and the biological component that is targeted for protection. However, biological systems are far more complex and dietary antioxidants may function via multiple mechanisms. It is critical to consider moving from using ‘the test tube’ to employing cell-based assays for screening foods, phytochemicals and other consumed natural products for their potential biological activity. The question then remains as to which cell models to use. Human immortalized cell lines derived from many different cell types from a wide range of anatomical sites are available and are established well-characterized models. The cytoprotection assay was developed to be a more biologically relevant measurement than the chemically defined antioxidant activity assay because it uses human cells as a substrate and therefore accounts for some aspects of uptake, metabolism and location of flavonoids within cells. Knowledge of structure activity relationships in the cytoprotection assay may be helpful in assessing potential in vivo cellular protective effects of flavonoids. This chapter will discuss the cytoprotective properties of flavonoids and focuses on the relationship between their cytoprotective activity, physicochemical properties such as lipophilicity (log P) and bond dissociation enthalpies (BDE), and their chemical structures. The factors influencing the ability of flavonoids to protect human gut cells are discussed, and these support the contention that the partition coefficients of flavonoids as well as their rate of reaction with the relevant radicals help define the protective abilities in cellular environments. By comparing the geometries of several flavonoids, its possible to explain the structural dependency of the antioxidant action of these flavonoids. Chapter 3 - The determination by Matrix-Assisted Laser Desorption/Ionization time–of- flight (MALDI-TOF) mass spectroscopy of the oligomeric nature of the two major industrial polyflvonoid tannins which exist, namely mimosa and quebracho tannins, and some of their modified derivatives indicates that: (i) mimosa tannin is predominantly composed of prorobinetinidins while quebracho is predominantly composed of profisetinidins, that (ii) mimosa tannin is heavily branched due to the presence of considerable proportions of "angular" units in its structure while quebracho tannin is almost completely linear. These structural differences also contribute to the considerable differences in viscoity of water Preface ix solutions of the two tannins. (iii) the interflavonoid link is more easily hydrolysable, and does appear to sometime hydrolyse in quebracho tannin and profisetinidins, partly due to the linear structure of this tannin, and confirming NMR findings that this tannin is subject to polymerisation/depolymerisation equilibria. This tannin hydrolysis does not appear to occur in mimosa tannin in which the interflavonoid link is completely stable to hydrolysis. (iv) Sulphitation has been shown to influence the detachment of catechol B-rings much more than pyrogallol-type B-rings. (vi) The distribution of tannin oligomers, and the tannins number average degree of polymerisation obtained by MALDI-TOF, up to nonamers and decamers, appear to compare well with the results obtained by other techniques. As regards procyanidin tannins, it has been possible to determine for mangrove polyflavonoid tannins that: (i) procyanidins oligomers formed by catechin/epicatechin, epigallocatechin and epicatechin gallate monomers are present in great proportions. (ii) oligomers, up to nonamers, in which the repeating unit at 528-529 Da is a catechin gallate dimer that has lost both the gallic acid residues and an hydroxy group are the predominant species. (iii) oligomers of the two types covalently linked to each other also occur. Water solution of non-purified polyflavonoid extracts appear to be incolloidal state, this being due mainly to the hydrocolloid gums extracted with the tannin as well as to the tannin itself. Commercial, industrially produced mimosa, quebracho, pine and pecan polyflavonoid tannin extracts water solutions of different concentrations behave mainly as viscous liquids at the concentrations which are generally used for their main industrial applications. Clear indications of viscoelastic response are also noticeable, among these the cross-over of the elastic and viscous moduli curves at the lower concentrations of the range investigated, with some differences being noticeable between each tannin and the others, pine and quebracho tannin extracts showing the more marked viscoelastic behaviour. Other than pH dependence (and related structural considerations), the parameters which were found to be of interest as regards the noticeable viscoelastic behaviour of the tannin extracts were the existence in the solutions of labile microstructures which can be broken by applied shear. This is supported by the well known thixotropic behaviour of concentrated, commercial polyflavonoid tannin extracts water solutions. Such microstructures appear to be due or (i) to the known colloidal interactions of these materials, or (ii) to other types of secondary interactions between tannin oligomers and particularly between tannin and carbohydrate oligomers. The latter is supported by the dependence of this effect from both the average molecular masses of the tannin and of the carbohydrate oligomers. The behaviour of polyflavonoid tannins as regards their antioxydant capacity and radical scavenging ability has been examined. Radical formation and radical decay reactions of some polyflavonoid and hydrolysable tannins has been followed, and comparative kinetics determined, for both light induced radicals and by radical transfer from a less stable chemical species to the tannin as part of an investigation of the role of tannin as antioxidants. The five parameters which appear to have a bearing on the very complex pattern of the rates of tannin radical formation and radical decay were found to be (i) the extent of the colloidal state of the tannin in solution (ii) the stereochemical structure at the interflavonoid units linkage (iii) the ease of heterocyclic pyran ring opening, (iv) the relative numbers of A- and B-rings hydroxy groups and (v) solvation effects when the tannin is in solution. It is the

Description:
Flavonoids, also referred to as bioflavonoids, are polyphenol antioxidants found naturally in plants. They are secondary metabolites, meaning they are organic compounds that have no direct involvement with the growth or development of plants. Flavonoids are plant nutrients that when consumed in the
See more

The list of books you might like

Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.