Incorporation of [4-(14)C] cholesterol into steryl derivatives and saponins of oat (Avena sativa L.) plants.

Sterols from both green and etiolated oat plants (Avena sativa) contain sitosterol, stigmasterol, cholesterol, Δ(7)-stigmastenol, Δ(7)-cholestenol and campesterol. In the saponin fraction avenacosides A and B and 26-desgluco-avenacosides A and B were detected. Etiolated plants incorporated [4-(14)C] cholesterol into steryl derivatives (esters, glycosides and acylated glycosides) and also into all of the 4 saponins. [4-(14)C] sitosterol, however, is incorporated only into steryl derivatives, but not in saponins. From this it is concluded that cholesterol, but not sitosterol is the in vivo precursor of oat saponins.