ABSTRACT
Phytochemicals are plant secondary metabolites derived from distinct biosynthetic pathways in plants. Their reactions are in some cases complex and require several enzyme catalyses. They are of diverse activities due to their numerous structural biological activities, which are relayed based on their importance in various pharmacological effects. The pentose phos-phate, shikimate, malonyl-CoA, nucleotide metabolic, and mevalonate pathways are among the contributing pathways for phytochemical biosyn-thesis. These biosynthetic pathways, enzymes, and precursors of alkaloids, anthocyanidins, anthraquinones, flavonoids, glycosides, lignans, pheno-lics, saponins, steroids, and terpenoids are discussed further in this chapter. These pathways have been studied, in some cases to provide alternative means of obtaining phytochemicals in larger quantities with the aim to apply them in bioengineering, pharmaceutics, and nutraceuticals as well as in other fields.
