Lanostanes

Lanosterol is a tetracyclic triterpenoid and is the compound from which all animal and fungal steroids are derived. By contrast, plant steroids are produced via cycloartenol. In the eyes of vertebrates, lanosterol is a natural constituent, having a role in maintaining health of the lens. Lanosterol is the precursor to cholesterol.

Lanostane or 4,4,14α-trimethylcholestane is a tetracyclic chemical compound with formula . It is a polycyclic hydrocarbon, specifically a triterpene. It is an isomer of cucurbitane.

Cucurbitane is a tetracyclic chemical compound with formula . It is a polycyclic hydrocarbon, specifically triterpene. It is also an isomer of lanostane (specifically 19(10→9β)-abeolanostane), from which it differs by the formal shift of a methyl group (carbon number 19) from the 10 to the 9β position in the standard steroid numbering scheme.