Parkeol

Parkeol is a relatively uncommon sterol secondary metabolite found mostly in plants, particularly noted in Butyrospermum parkii (now called Vitellaria paradoxa, or the shea tree). It can be synthesized from cycloartenol under Brønsted and Lewis acidic conditions, as a minor product by several oxidosqualene cyclase enzymes, and is the sole product of the enzyme parkeol synthase.

Parkeol is the dominant sterol found in the planctomycete Gemmata obscuriglobus, a rare example of a sterol-synthesizing prokaryote. The only other sterol identified in this organism is lanosterol, a key component of the sterol biosynthetic pathway in animals and fungi; this relatively limited sterol repertoire may resemble the early evolution of sterol synthesis, which is ubiquitous in eukaryotes.