Last stages in the biosynthesis of antirrhinoside
1995
Damtoft, S. | Jensen, S.R. | Schacht, M.
Feeding experiments with 2H-labelled precursors have now shown that the last steps in the biosynthesis of antirrhinoside in Antirrhinum majus involve an initial hydroxylation of the 6-position of 6,10-dideoxyaucubin to give linaride (10-deoxyaucubin), followed by epoxidation to give 10-deoxycatalpol (5-deoxyantirrhinoside) and finally hydroxylation of the 5-position to give antirrhinoside. 10-Deoxycatalpol was prepared by epoxidation of 10-deoxyaucubin with H2O2/WO3. Additionally, the iridoid content of two other species of Antirrhinum, namely A. speciosum and A. sicculum was investigated. In the first of these 10-deoxcatalpol was isolated for the first time from a plant together with antirrhinoside, linaride (10-deoxyaucubin) and macfadienoside. Antirrhinum sicculum contained 5-glucosyl antirrhinoside as the main iridoid together with antirrhinoside and macfadienoside.
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