This comprehensive review discusses the biosynthesis and catabolism of flavonoids and their regulation in plants. This interesting work approaches the subject matter from both a historical and methodological point of view. It places emphasis on key regulatory enzymic steps in the two pathways leading to the flavonoid basic units as well as the overall pathway within the flavonoid group. This special volume focuses on the known cell-free enzymology at the C15 level, as well as isotopic tracer studies involving the still unknown enzymic steps. This up-to-date text is an excellent resource for all plant physiologists, biological chemists, phytochemists and chemical ecologists.
Revised and expanded throughout, this blue-ribbon reference emphasizes the latest developments in the identification, utilization, and analysis of flavonoids for the prevention of disease and maintenance of good health-examining the processes involved in the absorption, metabolism, distribution, and excretion of these compounds and the impact of biotransformation on flavonoid function.
Flavonoids are ubiquitously present in plant-based foods and natural health products. The molecule of flavonoids is characterized by a 15-carbon skeleton of C6–C3–C6, with the different structural configuration of subclasses. The major subclasses of flavonoids with health-promotional properties are the flavanols or catechins (e.g., epigallocatechin 3-gallate from green tea), the flavones (e.g., apigenin from celery), the flavonols (e.g., quercetin glycosides from apples, berries, and onion), the flavanones (e.g., naringenin from citrus), the anthocyanins (e.g., cyanidin-3-O-glucoside from berries), and the isoflavones (e.g., genistein from soya beans). Scientific evidence has strongly shown that regular intake of dietary flavonoids in efficacious amounts reduces the risk of oxidative stress- and chronic inflammation-mediated pathogenesis of human diseases such as cardiovascular disease, certain cancers, and neurological disorders. The physiological benefits of dietary flavonoids have been demonstrated to be due to multiple mechanisms of action, including regulating redox homeostasis, epigenetic regulations, activation of survival genes and signaling pathways, regulation of mitochondrial function and bioenergetics, and modulation of inflammation response. The role of flavonoids on gut microbiota and the impact of microbial metabolites of flavonoids on optimal health has begun to unravel. The complex physiological modulations of flavonoid molecules are due to their structural diversity. However, some flavonoids are not absorbed well, and their bioavailability could be enhanced through structural modifications and applications of nanotechnology, such as encapsulation. This Special Issue consists of four review articles on flavonoids and 15 original research articles, which cover the latest findings on the role of dietary flavonoids and their derivatives in disease prevention and treatment.
Flavonoids are abundant secondary metabolites found in plants and fungi that have various roles in these organisms, including pigmentation, cell signalling, plant defence and inter-organism communication. Due to their abundance in nature, flavonoids are also important components of the human diet, and the last four decades have seen an intense study focused on the structure characterization of flavonoids and on their roles in mammal metabolism. This book reviews most of the well-established activities of flavonoids, and we also present more recent research studies on the area of flavonoids, including the chemical aspects of structure characterization of flavonoids, the biosynthesis of flavonoids in model plants as well as their role in abiotic stress situations and in agriculture, the role of flavonoids in metabolism and health and their importance in foods, from consumption to their use as bioactive components.
The use of antioxidants in sports is controversial due to existing evidence that they both support and hinder athletic performance. Antioxidants in Sport Nutrition covers antioxidant use in the athlete ́s basic nutrition and discusses the controversies surrounding the usefulness of antioxidant supplementation. The book also stresses how antioxidants may affect immunity, health, and exercise performance. The book contains scientifically based chapters explaining the basic mechanisms of exercise-induced oxidative damage. Also covered are methodological approaches to assess the effectiveness of antioxidant treatment. Biomarkers are discussed as a method to estimate the bioefficacy of dietary/supplemental antioxidants in sports. This book is useful for sport nutrition scientists, physicians, exercise physiologists, product developers, sport practitioners, coaches, top athletes, and recreational athletes. In it, they will find objective information and practical guidance.
Offering a wide ranging view of this important class of plant pigments, after a brief examination of the history & literature of flavonoids, this book explores structural variation of all subclasses of flavonoids, techniques for isolation, purification, & determination of structures, chemical syntheses, biosynthesis & genetics, patterns of distribution in the plant kingdom, & uses. Lastly, the functions of flavonoids in nature are investigated, as well as ways in which these compounds may have a more direct impact upon the human race. Contents: Introduction & Historical Perspective * Structural Variation * Occurrence & Distribution of Flavonoids * Extraction, Purification, & Identification of Flavonoids * Synthesis & Interconversions of Flavonoids * Biosynthesis & Genetics * Flavonoid Functions in Nature * Human Uses of Flavonoids
Recent years have seen tremendous progress in unraveling the molecular basis of different plant-microbe interactions. Knowledge has accumulated on the mecha nisms of the microbial infection of plants, which can lead to either disease or resistance. The mechanisms developed by plants to interact with microbes, whether viruses, bacteria, or fungi, involve events that can lead to symbiotic association or to disease or tumor formation. Cell death caused by pathogen infection has been of great interest for many years because of its association with plant resistance. There appear to be two types of plant cell death associated with pathogen infection, a rapid hypersensitive cell death localized at the site of infection during an incompatible interaction between a resistant plant and an avirulent pathogen, and a slow, normosensitive plant cell death that spreads beyond the site of infection during some compatible interactions involving a susceptible plant and a virulent, necrogenic pathogen. Plants possess a number of defense mechanisms against infection, such as (i) production of phytoalexin, (ii) formation of hydrolases, (iii) accumulation of hydroxyproline-rich glycoprotein and lignin deposition, (iv) production of pathogen-related proteins, (v) produc tion of oligosaccharides, jasmonic acid, and various other phenolic substances, and (vi) production of toxin-metabolizing enzymes. Based on these observations, insertion of a single suitable gene in a particular plant has yielded promising results in imparting resistance against specific infection or disease. It appears that a signal received after microbe infection triggers different signal transduction pathways.
Fruit and Vegetable Phytochemicals: Chemistry, Nutritional Value and Stability provides scientists in the areas of food technology and nutrition with accessible and up-to-date information about the chemical nature, classification and analysis of the main phytochemicals present in fruits and vegetables – polyphenols and carotenoids. Special care is taken to analyze the health benefits of these compounds, their interaction with fiber, antioxidant and other biological activities, as well as the degradation processes that occur after harvest and minimal processing.
The critically acclaimed laboratory standard for more than forty years, Methods in Enzymology is one of the most highly respected publications in the field of biochemistry. Since 1955, each volume has been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. Now with more than 300 volumes (all of them still in print), the series contains much material still relevant today-truly an essential publication for researchers in all fields of life sciences.This volume presents an extensive collection of new methodologies to aid progress in solving unanswered questions concerning the bioavailability and metabolism of flavonoids and polyphenols, their biochemical and molecular biological effects on cell regulation, and their effects on health. Major topics in this volume include sources, characterization, analytical methods, bioavailability, antioxidant action, and biological activity.
