Studies on biochemical transformation of plant steroids. Part III. Conversion of [14C]chiograsterol A into [14C]chiogralactone by a homogenate of Chionographic japonica maxim.

Abstract

Chionographic japonica contains a C₂₃ steroid, chiogralactone (3β, 16β-dihydroxy-6-oxo-24-nor-5α-cholan-23-oic acid 16β,23-lactone)(I), which is the first reported example containing a δ-lactone group. In order to elucidate its biosynthesis, labelled chiograsterol A(3β,16β,23,24-tetrahydroxy-5α-cholestan-6-one)(III) and B(5α-cholestan-3β,6β,16β,23,24-pentaol) were incubated with the homogenate from the whole Chionographic japonica plant at 27° for 6hr. The results indicate that chiograsterol A is converted into chiogralactone, whereas chiograsterol B is not so converted by the action of the plant enzyme.