METHODS IN PLANT BIOCHEMISTRY plant phenolics

• Main Author: Harborne, J. B (Author)
• Format: Book
• Language: English
• Published: London Academic Press 1989
• Subjects: Botanical chemistry
• Online Access: Click Here to View Status and Holdings.
• Item Description: Library has Vol. 1# Includes bibliographical references and index
• Physical Description: xii, 552 pages illustrations 25cm
• ISBN: 0124610110

In spite of the considerable body of current research on the biochemistry of plant polyphenols and of their importance in the agricultural and food industries, no comprehensive treatment of their methodology has yet appeared. The need to character ise phenolics on a microscale has been highlighted recently by the discoveries of the roles of particular phenols as signal molecules in crown gall infection, in rhizobial nitrogen fixation, in slime mould differentiation and in pollination mechanisms of Arums. Much has been written elsewhere on the chemistry and biochemistry of these substances, and particularly of the flavonoids, but the references to methods of isolation and identification are scattered throughout the literature and the available reviews are limited in their coverage of the many different classes of polyphenol that are now distinguished. In the present volume, therefore, an opening chapter is devoted to the detection of phenolic substances in crude plant extracts, the methods required to determine which classes they belong to and the methods available for the quantitative estimation of total phenol. The remaining fourteen chapters then outline in turn the procedures available for the extraction, isolation, separation and characterisation of each major class, from simple phenols and phenolic acids through the many flavonoids to xanthones and lichen constituents. There are necessary introductions to the chemistry, structural variation. function and distribution of each class and, in a few cases where this is practicable, detailed listings are given of known derivatives. Emphasis is given in most chapters to chromatographic separations, and high performance liquid chromatography, because of its increasing importance in phenolic research, receives particular attention. However, thin layer and paper Rf values are also included with HPLC retention times, since TLC and PC continue to provide very flexible systems for phenolic identification. Ultraviolet spectral techniques for phenolic identification and quantification, which were pioneered during the 1950s, are still widely used and are applicable to all classes of polyphenol. However, NMR spectral techniques of ever increasing sophistication are now available for the structural elucidation of novel molecules and the use of NMR spectroscopy is highlighted in almost every chapter. In spite of all the advances in spectroscopy, chemical rearrangements, degradations and syntheses still have a part to play in the comprehensive and thorough identification of these plant molecules. Biochemical techniques, notably enzymic hydrolyses, also contribute to the characteri of those polyphenols which occur naturally in conjugated form. In preparing this book for publication,