The Science Of Flavonoids

This is the only book of its kind to provide an overview of the science of flavonoids in plants.

"In this book, two of the primary sources of flavonoids, i.e. plants and fruits (oranges to be specific) are comprehensively reviewed, along with their flavonoid content and antioxidant activity (including action against COVID-19) and toxicity. Besides, a general overview of the analytical techniques for flavonoids determination in their natural sources is provided. Finally, a detailed description of flow techniques and their evolution, together with their role in the automation of the sample pretreatment and its combination with separation techniques, is also included"--

Advances in the flavonoid field have been nothing short of spectacular over the last 20 years. While the medical field has noticed flavonoids for their potential antioxidant, anticancer and cardioprotectant characteristics, growers and processors in plant sciences have utilized flavonoid biosynthesis and the genetic manipulation of the flavonoid pa

About 1958, the late Professor R. E. ALSTON and Professor B. L. TURNER, both of the Department ofBotany, The University ofTexas at Austin, initiated a general systematic investigation ofthe legurne genus Baptisia. They found that flavonoid patterns, as revealed by two-dimensional paper chromatography, were valid criteria for the recognition of the Baptisia species and for the documentation of their numerous natural hybrids. Later, they showed that the flavonoid chemistry could be used for the analysis of gene flow among populations. At that time no attempt was made to even partially identify the flavonoids which were detected chromatographically. Neverthe1ess, it soon became apparent that the full value of the chemical data for systematic purposes required knowledge of the structures of the flavonoids. In 1962, one of us (T.J.M.) in collaboration with Drs. ALSTON and TURNER beg an the chemical analysis of the more than 60 flavonoids which had been chromatographi cally detected in the 16 Baptisia species. In the intervening years, a number of chemists and botanists, inc1uding Drs. K. BAETCKE, B. BREHM, M. CRANMER, D. HORNE, J. KAGAN, B. KROSCHEWSKY, J. MCCLURE, H. RÖSLER, and J. WALLACE, participated in the devel opment of techniques and procedures for the rapid identification of known flavonoids and in the structure determination of new flavonoids. In addition, the flavonoid chem istry of many plants other than Baptisia was investigated.

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

The flavonoids, one of the most numerous and widespread groups of natural constituents, are important to man not only because they contribute to plant colour but also because many members (e.g. coumestrol, phloridzin, rotenone) are physiologically active. Nearly two thousand substances have been described and as a group they are universally distributed among vascular plants. Although the anthocyanins have an undisputed function as plant pigments, the raison d'etre for the more widely distributed colourless flavones and flavonols still remains a mystery. It is perhaps the challenge of discovering these yet undisc10sed functions which has caused the considerable resurgence of interest in flavonoids during the last decade. This book attempts to summarize progress that has been made in the study of these constituents since the first comprehensive monograph on the chemistry of the flavonoid compounds was published, under the editorship of T. A. Geissman, in 1962. The present volume is divided into three parts. The first section (Chapters 1-4) deals with advances in chemistry, the main emphasis being on spectral techniques to take into account the re cent successful applications of NMR and mass spectral measurements to structural identifications. Recent developments in isolation techniques and in synthesis are also covered in this section. Advances in chemical knowledge of individual c1asses of flavonoid are mentioned inter aha in later chapters of the book.

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 presence of contaminant flavonoids in vitamin C preparations from citrus fruits initially led Szent-Gyorgyi and his collaborators to suggest that a flavonoid compound, with biological activity for the prevention of capillary fragility, was vitamin P. Later re search, although not disproving biological activity, discontinued the use of the vitamin classification for these compounds. However, the ubiquitous distribution of flavonoids in living organisms, and the continued discovery of various activity in biological systems makes these compounds targets of wide ranging investigation. This volume is primarily based on a Symposium on Flavonoids and related com pounds held during the 212th National Meeting of the American Chemical Society held in Orlando, Florida on August 28-29, 1996 under the sponsorship of the Division of Agricul tural and Food Chemistry. While the book is not intended to be a comprehensive volume on flavonoid research, the papers provide various approaches to exploring the biological functions of flavonoids in plants and animals, their chemical modifications for enhanced activity, some analytical techniques, as well as their use in food classification. A signifi cant portion is devoted to medicinal implications of these compounds. The organizers would like to express their appreciation to Tropicana Products, Inc., Bradenton, Florida, Coca-Cola Foods Division, Plymouth, Florida and the American Chemical Society's Division of Agricultural and Food Chemistry for financial support. Of course, the book could not be produced without the authors, whose cooperation and pa tience is greatly appreciated.