Indole Alkaloids from Catharanthus roseus Tissue Cultures IV1: 16R-19,20-E-Isositsirikin, 16R-19,20-Z-Isositsirikin and 21-Hydroxycyclolochnerin.

From CATHARANTHUS ROSEUS cell suspension cultures 16 R-19,20- E-isositsirikine ( 1), 16 R-19,20- Z-isositsirikine ( 2) and a new sarpagine type indole alkaloid ( 5) have been isolated. The structures have been deduced from spectroscopic data; that of 5 has been confirmed by X-ray analysis.