4 matokeo
Ten new indole alkaloids (1-10) comprising five ibogan, two aspidosperman, one vincamine, and two bisindole alkaloids, in addition to 32 known alkaloids, were isolated from the stem-bark extract of a Malayan Tabernaemontana corymbosa. The structures of these alkaloids were determined based on
Besides sweroside ( 1) two main alkaloids were isolated from twigs and leaves of Tabernaemontana psorocarpa and shown to be 12-methoxy-17,18-dehydrovincamine ( 2) and 16-epi-isositsirikine ( 3) respectively.
The isolation of the alkaloids from two different samples of stem bark of Tabernaemontana psorocarpa is described. Both samples contained 16-epi-isositsirikine as the major alkaloid but differed from each other in the number and quantity of the other alkaloids. The following minor alkaloids were
Two seco-tabersonine alkaloids, jerantiphyllines A and B, in addition to a tabersonine hydroxyindolenine, jerantinine H, and a recently reported vincamine alkaloid 7, were isolated from the leaf extract of the Malayan Tabernaemontana corymbosa and the structures were established using NMR and MS