ジギタリスに関する研究 (第5報)

ジギタリス・プルプレアのB系配糖体とJensenの螢光定量用試薬の反応成績体その2 Digitalinum verumまたはStrospesideとJensenの螢光定量用試薬との反応中間生成物について

抄録

Intermediates in the reaction of digitalinum verum or strospeside with Jensen's reagent for determination of B series glycosides of Digitalis purpurea L. were isolated and identified as their Δ^{14, 16}-dianhydro derivatives. The fluorescence of solutions of these substances was found to be stronger than that of a solution in the same concentration of Δ^{14, 16}-dianhydrogitoxigenin. Thus, it was found that the reason why determination of digitalinum verum and strospeside with Jensen's reagent gave values higher than the theoretical one for the first several hours is due to the formation of such intermediates.
It was also found that there are two groups in the B-series glycoside of Digitalis purpurea L., one of which is first hydrolized by Jensen's reagent to gitoxigenin and then dehydrated to Δ^{14, 16}-dianhydrogitoxigenin, while the other is first dehydrated by the reagent to Δ^{14, 16}-dianhydroglycosides and then hydrolized to Δ^{14, 16}-dianhydrogitoxigenin. Consequently, in the latter case, if the determination is conducted in the presence of Δ^{14, 16}-dianhydroglycoside, a value higher than theoretical one is obtained, because the fluorescence of Δ^{14, 16}-dianhydroglycosides is stronger than that of Δ^{14, 16}-dianhydrogitoxigenin.
It is necessary, therefore, to effect the determination after Δ^{14, 16}-dianhydroglycoside has changed into Δ^{14, 16}-dianhydrogitoxigenin.