ABSTRACT
Since the totality of phytoestrogens is phenylpropanoids, particular attention will be devoted to the biosynthesis and ecological and physiological role of these compounds in plant species. Traditionally plant chemicals are classified as primary or secondary constituents, depending on whether or not they have an essential role in plant metabolism and are universally present in all plants. Considering that elicitation is probably the most effective approach for increasing yields of plant secondary metabolites, the understanding of the mechanisms involved in the regulation of secondary metabolism is of paramount importance in order to define for different plant species the optimal culture conditions ensuring the high energetic flux into secondary metabolic pathways. Precursors usually derive from basic pathways of primary metabolism, such as glycolysis, fatty acid biosynthesis, Krebs cycle, and shikimate pathway. Transcription factors have been isolated and characterized for the metabolic pathway leading to flavonoid biosynthesis.
