What is "withanolide"

n. Any of a group of naturally occurring chemical compounds occurring as secondary metabolites primarily in genus of the nightshade family. They consist of a steroid backbone bound to a lactone or one of its derivatives.

Withanolides are a group of at least 300 naturally occurring chemical compounds. They occur as secondary metabolites primarily in genera of the Nightshade family, for example in the tomatillo.

Structurally, withanolides consist of a steroid backbone bound to a lactone or one of its derivatives; they are produced via oxidation of steroids. It remains unknown to what end withanolides are produced; they may act as deterrent for feeding insect larva and other herbivores.

In the laboratory, many withanolides exhibited medicinally interesting properties.

Genera within the nightshade family that have been found to produce withanolides include: Datura, Dunalia, Iochroma, Lycium, Nicandra, Physalis, Salpichroa, Solanum, Withania, and Jaborosa.

This class of steroidal lactones involves an ergostane-type framework in which C-22 and C-26 are appropriately oxidised to form a (delta)-lactone ring. They are subdivided into nine groups: withanolides, withaphysalins, physalins, nicandrenones, jaborols, ixocarpalactones, perulactones, acnistins and miscellaneous withasteroids.