Abstract Simultaneous administration of a mixture of [21- 3 H]-3β, 20ξ-dihydroxy-23-nor-5β-cholanoic acid and [21- 14 C]-3β-hydroxy-5β-pregnan-20-one to Digitalis purpurea intact plants produced double labelled digitoxin. The 3 H: 14 C ratio of the cardenolide was considerably higher than the 3 H: 14 C ratio of the administered substrates. This result indicates that in the main biosynthetic pathway
摘要 [21- 3 H]-3β、20ξ-dihydroxy-23-nor-5β-cholanoic acid 和 [21- 14 C]-3β-hydroxy-5β-pregnan-20-one 的混合物对紫洋地黄同时给药完整的植物产生双标记的
洋地黄毒苷。Cardenolide 的 3 H: 14 C 比率显着高于所施用底物的 3 H: 14 C 比率。该结果表明,在从 20-酮孕烷到心内酯的主要
生物合成途径中,C-20 处的
乙酸酯单元的引入应该发生在 C-21 处的羟基化之前。