Phytochemicals classification

See also Anemia Iron-Deficiency Anemia. Phytochemicals Classification and Occurrence Epidemiological Factors. Supplementation Dietary Supplements. 

Phytochemicals are biologically-active, non-nutritive secondary metabolites which provide plants with colour, flavour and natural toxicity to pests. The classification of this huge range of compounds is still a matter of debate, but they fall into three main groups ... 

The discovery that, in industrialised societies, diets deficient in fruits and vegetables can effectively double the risk of developing many different types of cancer has focused renewed attention on the beneficial properties of these foods (Block e/a/., 1992 Patterson ef a/., 1990 Southon and Faulks, 2002). As we have seen, plant foods are rich in micronutrients, but they also contain an immense variety of biologically active secondary metabolites providing colour, flavour and natural toxicity to pests and sometimes humans (Johnson et ah, 1994). The chemistry and classification of such substances is still a matter for much research and debate, but this has not prevented attempts to isolate and exploit substances that have variously been termed protective factors , phytoprotectants , phytochemicals and nutraceuticals . Phytochemical compounds include ... 

Lienert, D., Anklam, E., and Panne, U. 1998. Gas chromatography—mass spectral analysis of roots of Echinacea species and classification by multivariate data analysis. Phytochem. Anal. 9, 88-98. 

Many chemotaxonomic studies have been published that consists of lists of phytochemical data, but a significant number of studies are now appearing that probe such questions as the genetics of terpenoid formation, hybridization and clonal variation, and biochemical evolution. Reviews have appeared on the chemotaxonomy of flowering plants,435 and of terpenoid formation in particular,436 on chemistry in botanical classification,437 on leaf oils of conifers,438 and on biochemical evolution in plants 439 the last named is comprehensive and quite outstanding. 

Polhill, R.M. (1994) Classification of the Leguminosae, in Phytochemical Dictionary of the Leguminosae (ed. l.W. Southon). Chapman Hall, London, pp. 35-57. 

Further systematic classification at the level of families and subfamilies using the patterns of betalains is possible only in a few cases (see below). The majority of chemotaxonomic work on members of the Caryophyllales has been concentrated on flavonoids (101). More investigations, especially on the basis of sound phytochemical work as well as extensive screening data, for example, with the aid of HPLC, are needed. Table I summarizes the distribution of betalains in the Caryophyllales (only well-characterized compounds are listed). 

The diterpenoids are a large and ubiquitous family of isoprenoids derived from 2E,61% ] 0 -geranylgeranvl pyrophosphate. Of all the families of natural products, the diterpenoids have one of the widest ranges of biological activity. The clearest classification of the cyclic diterpenoids (abietane, labdane, clerodane,...) is based on biogenetic considerations. The variety of structural types found amongst the diterpenoids has led to their use as phytochemical markers. Indeed, many of the diterpenoids found in recent years have been isolated in the course of phytochemical surveys of the Compositae. 

Classification Phytochemical Definition Predominant flavonoid in iemons and sweet oranges Empirical C28H34O15... 

Details about structure, biosynthesis, and classification of phenolics are described in the other chapters in this handbook. Plant phenolics have a distinctive ability to form non-covalent, intermolecular complexes with each other and with both large and small molecules. Recognition of the antioxidant activities of many polyphenols has established correlation with the health benefits by such compounds [34]. This leads to the development of commercial products containing free-radical-scavenging phytochemical mixtures, for example, Pycnogenol (procyanidin extracted from Pinus maritima). Table 82.2 represents a list of polyphenolic compounds used in nutraceuticals and their biologic effects on human health. 

Genera in bold = significant for this book (studies on secondary metabolites published) genera in standard type = no phytochemical results available underlined genera = classification different from the phylogenetic tree based on (DNA) molecular analysis (see Fig. 2.2)... 

Genera in bold indicate the presence of phytochemical data in the literature for this specific genus (otherwise there are no data available). Genera with a question mark listed under Appendix have been nested within a clade according to the traditional classification of Hunziker (2001) due to the lack of molecular data for this specific genus. 

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