PHENOLIC COMPOUND BIOCHEMISTRY ppt

[...]... Gainesville, FL R L Nicholson Professor of Botany and Plant Pathology, Purdue University, West Lafayette, IN FAMILIES OF PHENOLIC COMPOUNDS AND MEANS OF CLASSIFICATION 1 Chapter 1 FAMILIES OF PHENOLIC COMPOUNDS AND MEANS OF CLASSIFICATION 1 DEFINITIONS What are phenolic compounds? They are compounds that have one or more hydroxyl groups attached directly to an aromatic ring Phenol (1.1) is the structure... molecules Of course such polymers exist Phenolic compounds are characteristic of plants and as a group they are usually found as esters or glycosides rather than as free compounds It is important to realize this if you want to extract phenols from plant tissues 2 CLASSIFICATION The term phenolics covers a very large and diverse group of chemical compounds These compounds can be classified in a number... Simmonds (1964) classified these compounds into groups based on the number of carbons in the molecule (Table 1.1) Table 1-1 Classification of phenolic compounds Structure Class C6 C6 - C1 C6 - C2 C6 - C3 C6 - C3 C15 C15 C15 C15 C15 C15 C15 C30 C6-C1-C6, C6-C2-C6 C6, C10, C14 C18 Lignans, neolignans Lignin Tannins Phlobaphenes simple phenolics phenolic acids and related compounds acetophenones and phenylacetic... of phenolic compounds and means of classification 3 1 Widely distributed phenols – ubiquitous to all plants, or of importance in a specific plant 2 Phenols that are less widely distributed – limited number of compounds known 3 Phenolic constituents present as polymers In this chapter each of the classes will be discussed, and structures of commonly found or important compounds will be presented The compounds... commonly found or important compounds will be presented The compounds will be presented in the order listed in Table 1-1 The main focus will be on phenolic compounds that are widely distributed 3 CLASSES OF PHENOLIC COMPOUNDS 3.1 Simple phenolics Simple phenolics are substituted phenols The ortho, meta and para nomenclature refers to a 1,2-, 1,3- and 1,4-substitution pattern of the benzene ring, respectively,... the role of phenolic compounds in plant defense We have included a number of examples, including phytoanticipins, phytoalexins and lignin synthesized in response to pathogen attack, to complement the more chemical nature of the other chapters, and to illustrate the important role phenolic compounds play in plant survival The final chapter is an overview of some of the positive effects phenolics can... vic-tri Figure 1-1 Nomenclature for substitution patterns of phenolic compounds R, R1 and R2 are generic substituents Examples include resorcinol (1,3-dihydroxybenzene; 1.2), a metadihydroxylated simple phenolic, and phloroglucinol (1,3,5-trihydroxybenzene; 1.3), a meta-trihydroxylated simple phenolic 4 Chapter 1 OH HO OH HO (1.2) 3.2 OH (1.3) Phenolic acids and aldehydes Hydroxy-benzoic acids are characterized... three compounds are esterified to the γ-carbon of the monolignols These compounds are found in higher quantities in certain mutants or genetically engineered plants in which the expression of specific lignin biosynthetic genes has been altered (Sederoff et al., 1999; Boerjan Families of phenolic compounds and means of classification 21 et al., 2003; Ralph et al., 2004) The presence of these compounds...xii Contents Preface advances in the identification of phenolic compounds have been made possible through the development of mass spectrometry, we have dedicated an entire chapter to the use of mass spectrometry in the identification of phenolic compounds (Chapter 5) This chapter was written by Dr Karl V Wood of the Mass Spectrometry Facility in the... is attached to a chain of carbons The phenolic hydroxyl group, however, is influenced by the presence of the aromatic ring Because of the aromatic ring, the hydrogen of the phenolic hydroxyl is labile, which makes phenols weak acids We will deal with their chemical properties separately in Chapter 2 1 2 Chapter 1 Polyphenols are compounds that have more than one phenolic hydroxyl group attached to one . h0" alt="" Chapter title i PHENOLIC COMPOUND BIOCHEMISTRY Contents iii PHENOLIC COMPOUND BIOCHEMISTRY By WILFRED VERMERRIS University. Families of Phenolic Compounds and Means of Classification 1. Definitions 1 2. Classification 2 3. Classes of phenolic compounds 3 3.1 Simple phenolics