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.[1] 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.
The biosynthesis of lanosterol has been intensively investigated.[2]
| Description | Illustration | Enzyme | - | - | Squalene is oxidized to 2,3-oxidosqualene (squalene epoxide) | - | 2,3-Oxidosqualene is converted to a protosterol cation and finally to lanosterol | - | (step 2) | (step 2) |
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Elaboration of lanosterol under enzyme catalysis leads to other steroids. 14-Demethylation of lanosterol by CYP51 eventually yields cholesterol.
As a molecule naturally enriched in the eye lens, lanosterol is a component involved in maintenance of lens clarity.[3] [4] Its proposed mechanism of action is to inhibit the aggregation of crystallin proteins, which contribute to the clouding of vision by forming cataracts.[3] [4]
Lanosterol is under research for its potential as a therapeutic additive in eye drops to inhibit the aggregation of crystallin proteins and dissolve cataracts.[3] [4] However, supplemental lanosterol in eye drops appears to have limited solubility and poor bioavailability in the eye, and has not proved effective for inhibiting cataracts, as of 2020.[3] [4]