Phytoecdysteroids: Natural Sources, Biosynthesis, and Structural Classification

This chapter reviews the general chemical properties and ecological roles of phytoecdysteroids. Phytoecdysteroids are steroid compounds found in plants that are structurally similar to insect molting hormones. The chapter highlights their distribution in the plant kingdom, particularly within the families Caryophyllaceae, Amaranthaceae, and Lamiaceae, and their importance in defense against insect predators and in adapting to stress. It also explains the biosynthetic pathway from cholesterol, the aglycone core, and the structural diversity that occurs through various modifications. It shows how environmental conditions, developmental stage, and genetic factors affect their accumulation. Additionally, they are compared with insect ecdysteroids, and the chemical and taxonomic aspects are discussed. Thus, the chapter provides a brief scientific background for the detailed discussions that follow.