AbstractAs a result of our interest in the Rauwolfia alkaloids we have undertaken in these labortories a systematic study if other genera of the family Apocynaccae, in particular the members of the subfamily Plumeroideae. This subfamily contains several species which are known to be abundant in alkaloids. (e.g. Aspidospermia, Tabernacmoniana, Tabernanthe, Voacanga, Rauwolfia, etc.)
Among the genera which were examined was the African hardwood Tabernanthe iboga Baill. This plant has been the subject of intensive investigations by several groups. More recently Taylor and co-workers have elucidated the structures of alkaloids occurring in this plant.
The following alkaloids have been isolated from this plant; ibogaine, tabernanthine, ibogamine, iboluteine, iboquine, desmethoxyiboluteine, and hydroxyindolenine derivatives of ibogaine and ibogamine, voscangine, gabonine, kisanthine, and kimvulline.
Of these the hydroxyindolenine derivatives as well as iboluteine, desmethoxyiboluteine, and iboquine could also be formed by the easy autooxidation of the parent alkaloids during the process of isolation.
During the course of our investigation small amounts of a presumably new alkaloid, ibogaline, were isolated.
The commercial bark was processed by a scheme described in detail in the Experimental section, fractionation being accomplished by taking advantage of the solubility of ibogaine and congeners in ether.