Biosynthesis of Secondary Metabolites in Plants as Influenced by Different Factors

Plant secondary metabolites (PSMs) are essential in plant defense mechanisms hostile to environmental stresses and offensive attacks by pathogens. PSMs are not only necessary for plant development, but also they are widely used as natural bioactive compounds with significant biological functions. In the recent medications, several PSMs are used as prime composites to cure many diseases. Various factors might influence the synthesis of PSMs in plants. This chapter contribution aims to discuss the most important factors affecting the biosynthesis of PSMs, including biotic and abiotic factors, biosynthetic pathways, effect of light intensity, stress-related influence, use of bioreactors, immobilization, and production of PSMs in other host cells. Additionally, elicitation and metabolic engineering approaches to increase the PSMs production from various medicinal herbs are discussed. This update delivers a brief outline about the synthesis of major classes of natural compounds, including alkaloids, phenylpropanoids, polyketides, and terpenoids in various plant species.