Ecdysteroide

Ecdysteroids are a class of steroid hormones and hormone-like compounds that regulate development in arthropods and occur as natural products in some plants. The principal molting hormone in insects is ecdysone, which is converted in target tissues to the biologically active 20-hydroxyecdysone. In arthropods, pulses of ecdysteroids coordinate molting, metamorphosis, and reproduction, while in some crustaceans similar hormones play related roles.

Chemically, ecdysteroids have a steroid-like four-ring core with various hydroxy groups and side chains. They are synthesized from cholesterol through a series of enzymatic steps that generate ecdysone, which is then converted to 20-hydroxyecdysone in target tissues. The ecdysteroid receptor is a nuclear receptor complex, typically EcR bound to Ultraspiracle (USP) in insects, which upon ligand binding activates transcription of ecdysone-responsive genes.

Distribution: Insects and other arthropods produce endogenous ecdysteroids; plants also synthesize phytoecdysteroids, presumably for defense against herbivory. These plant compounds can be structurally similar to insect ecdysteroids but often occur at lower biological activity in animals.

Applications and research: Because ecdysteroids control molting, synthetic analogs and related compounds have been developed as insect growth regulators for pest control. Some ecdysteroids are explored as dietary supplements or pharmacological tools, but evidence for health benefits in humans is limited, and safety data are variable. Research continues into their signaling pathways, receptor interactions, and potential medical utilities. Examples of synthetic ecdysteroid mimics used as insect growth regulators include tebufenozide and methoxyfenozide.