ABSTRACT
Triterpenes are a large group of naturally occurring substances with relatively complex cyclic structures consisting of a carbon skeleton based on six isoprene units. They are formed by “head-tohead” condensation of two farnesyl pyrophosphate units. The product of this reaction is an acyclic C30 hydrocarbon, squalene. The squalene can be formed both in plant and in animal organisms and plays a major role in the biosynthesis of 30-carbon triterpenes as well as steroids, which play many physiological functions in the synthesizing organisms. The cyclization of squalene leads to the formation of pentacyclic structures of oleane, ursane, and lupine type. The hydroxyl derivatives of these types are known under their trivial name, saponins. Their glycosylated forms can be found in many plant families.
