METABOLISM OF 24-EPI-CASTASTERONE AND 24-EPI-BRASSINOLIDE IN CELL-SUSPENSION CULTURES OF ORNITHOPUS-SATIVUS

Exogenously applied 24-epi-brassinolide and 24-epi-castasterone are tr ansformed by cell suspension cultures of Ornithopus sativus in a multi step pathway to give 20-keto-pregnane derivatives. As intermediates of these degradations 20R-hydroxy-3,24-bisepi-brassinolide and 20R-hydro xy-3,24-bisepi-castasterone, respectively, as well as 2 alpha, 3 beta- dihydroxy-5 alpha-pregnane-6,20-dione were isolated from the culture m edium and their structures were elucidated by means of H-1 NMR and mas s spectrometry. In addition to side-chain cleavage, 25-hydroxylation t o give 25-hydroxy-3,24-bisepi-brassinolide was also observed.