Taxonomy, Morphology, and Ecology of Medicinal Plants: A Botanical Perspective

Occurrence and Evolution .................................................................. 15 2.4 Plant Defense, the Costs of Secondary Metabolites, and Ecological Strategies ...................................................................................... 17

2.4.1 Trade-Off between Direct and Indirect Defense ................................ 17 2.4.2 Trade-Off between Primary and Secondary Metabolism .................. 18

2.5 Primary Metabolites with Therapeutic Potential ........................................... 19 2.5.1 Pectin .................................................................................................. 19 2.5.2 Lignin.................................................................................................. 19 2.5.3 Chlorophylls ........................................................................................20 2.5.4 Should Primary Metabolites and their Derivatives be Regulated? .... 21

2.6 Conclusions ..................................................................................................... 21 References ................................................................................................................ 21

The aim of this chapter was to introduce plant taxonomy and morphology and to explore why-from the perspective of the plant-biologically active compounds are produced. Thus, we shall present a view of plant morphology and biologically active compounds set within an evolutionary and ecological context. Also, we wish to dispel the traditional view that it is only the secondary metabolites of plants that can be exploited as sources of therapeutic drugs, that is, metabolites that do not contribute to primary metabolism and growth but have specialized roles, usually in plant defense or the attraction of animals for pollination or seed dispersal (Wink, 2004). A range of primary metabolites are now promising as potential therapies to ght some of the most insidious human diseases and disorders. Being plant primary metabolites, they can be readily found in great quantity.