Triterpene

Animals, plants and fungi all produce triterpenes, including squalene, the precursor to all steroids.

Squalene serves as precursor for the formation of many triterpenoids, including bacterial hopanoids and eukaryotic sterols.

Triterpenoids possess a rich chemistry and pharmacology (e.g. cholesterol) with several pentacyclic motifs.

[5][6] Steroids feature a cucurbitane core, although in practice they are biosynthesised from either lanosterol (animals and fungi) or cycloartenol (plants) via the cyclization of squalene.

They are produced by plants as part of their self-defense mechanism[7] with important sub-classes including ginsenosides[8] and eleutherosides.