THREE NEW STEROIDAL ALKALOIDS FROM THE BARK OF HOLARRHENA ANTIDYSENTERICA

Article abstract of DOI:10.1016/0031-9422(88)84121-9

Key Word Index-Holarrhena antodysenterica; Apocynaceae; bark; steroidal alkaloids; regholarrhenine A; regolarrhenine B; regolarrhenine C; structural determination.Three new steroidal alkaloids, namely regholarrhenie A, B, and C, isolated from the stem bark of Holarrhena anidysenterica collected at flowering stage are described.Structural studies on the basis of (1)H NMR, (13)C NMR, ORD, CD and mass spectral and chemical evidences show that the first two alkaloids lack the C-3 amino function in the conenine structure but possess a dienone system in ring A.In addition, both contain a hydroxy group at C-11 but differ in the nature of the nitrogen in the heterocyclic ring (tertiary and secondary amino group, respectively).Regholarrheine C is the partially demethylated enamine analogue of conessine where both the heterocyclic and C-3 nitrogens are secondary amine.